HDTT High Resolution Files

By Bill Heck

Record company vaults are filled with analog tapes of classical music performances. As with performances found on contemporary digital recordings, many are nice enough, but only vaguely worthy of preservation for posterity, while some others are eminently forgettable. But then there are those performances that are exceptional, that deserve special treatment to bring the performances to current listeners in the best sound possible. For High Definition Tape Transfers (HDTT), that means providing the best possible transfers of classic performances from the best analog tape they can find. These transfers are then made available in several formats, from CD to high resolution downloadable files.

John Puccio has already reviewed a number of performances on CDs from HDTT. But HDTT offers most of their transfers in multiple formats, ranging from CD resolution (PCM encoding, 16 bit / 44.1 KHz sampling rate) to PCM 24/352.8 and DSD 256. (For the uninitiated, with PCM files the first number, e.g. 16, refers to the number of digital bits per sample; the second, e.g., 44.1, refers to the number of thousands of samples per second. John does not have the equipment to play downloaded high-resolution files, i.e., greater than CD resolution, so he suggested that I try a few HDTT transfers in one of the high-res formats. My NAD C 658 can handle up to 24/192 resolution, so I went with that level.)

For those who have the capability to play high-res files, the process for HDTT files is quite simple. You order a recording, specifying the resolution that you would like; once you order, you receive a link via email that allows you to download the file. Note that high resolution files are large, and the higher the resolution, the larger the files; for example, the three 24/192 files that I downloaded each were around 1.7 GB. All this means that you need a decent internet connection so that the download doesn’t take forever, and you need plenty of disk space. Once you have downloaded the files, you can play them from your PC (if you connect the PC to your audio system), or copy them to a flash drive (to plug into the USB port of your DAC), or copy them to another drive (that you connect to your network where it can be read by your DAC). The main thing is that you need a DAC that can handle files of the resolution that you chose. If you have no idea what any of this means, you presumably don’t have a DAC/preamp to play high-resolution files.

Now, back to those performances that are worth preserving.

The major labels have reissued loads of classic – and not so classic – performances. Some of the reissues have been done with attention to detail, resulting in good to great sounding CDs; others perhaps not so much. However, in many cases, reissues from the early days of CDs have gone out of print, making those performances difficult to find at all.

Enter HDTT with the goal of providing better versions of a recorded performances from decades ago. On the surface, that sounds simple, but it must be a difficult business. To start with, you need to find early-generation tapes from which you can transfer and digitize the performances. You would think that “finding” would be simple, but alas, it may not be: in the worst case, the best tapes may have been destroyed; in other cases, the ravages of time may have damaged them even to the point of unplayability. In other cases, the desired tapes may be…well, somewhere, but not to be found among the thousands upon thousands of poorly inventoried reels. On the assumption that you indeed have access to an early generation tape, you need to have the equipment not just to play it any old way, but to play it in such a way as to recover its full musical potential. If you were starting with high resolution digital copies, that would be easy; with old analog tapes, it can be quite a chore.

All this means that the final product may indeed be the best possible, but may still involve compromises. On the other hand, with luck, the results can be amazingly good. Let’s review a couple of examples.

Andres Segovia: The Unique Art of Andres Segovia (HDTT9328)
In his day, Andres Segovia was the acknowledged master of the classical guitar, perhaps single-handedly (or perhaps we should say two-handedly) making the guitar respectable as a classical concert instrument. A Spaniard himself, many of Segovia’s performances are of works by Spanish composers, and his style remained what we might think of as “Spanish” throughout his very long career. But Segovia was hardly a one-trick pony: for example, he transcribed works by a number of composers, most notably J S Bach. (By the way, if you have never heard transcriptions of any of Bach’s music for guitar, be aware the some pieces can be revelatory, uncovering aspects of the music that are more difficult to hear when the music is played on the instruments for which it was written originally.) Post-Segovia, a number of great classical guitarists have arisen, but Segovia’s work still is well worth hearing.

At least in the modern period, Segovia recorded for Decca. Decca was quite well-regarded in the early period of stereo recording for their “ffrr” (Full Frequency Range Recording) technique.[i] So how did this set turn out?

For this particular album, comparison to a commercially available CD is complicated by the fact that the CD version is no longer available; I could not find even a used copy in a quick search. Discogs does list four used copies of the LP for sale at prices from $5 – 10, but as I no longer have a turntable, that was a non-starter, and anyway this review is supposed to compare the file to a readily available CD. To make things more perplexing, the album in question is not to be confused with the two-CD set released by DG called “The Art of Andres Segovia.” Nor should you confuse it with the 8 (?) CD series previously issued on MCA, then on DG, then on IDIS called “The Legendary Andres Segovia”. So far as I can tell, Segovia’s many recordings have been chopped up and repackaged in various combinations for decades. Sadly, most of these recordings have fallen out of their respective catalogs. Moreover, there is the distinct possibility that some, many, or all of the Decca master tapes of Segovia’s recordings were destroyed in the Universal Studios fire of 2008.

So what did I use for a CD to compare with the HDTT version of this album? Absent this exact album, I searched my few Segovia disks and found that Volume 7 of the aforementioned “Legendary” series on MCA began with the Milan Pavanas (Pavanes), and that the series of six pavanas comprise tracks 6 and 7 on the HDTT file. From what I can tell, the same original recordings were sources in both cases, so I used them as my standard of comparison.

In the discussion above, I mentioned some potential compromises because of imperfect sources. That concern applies here: the very first thing that I noticed in listening to this file was the result of one of the vagaries of the process. I cued up Milan’s Pavana 1 on the HDTT file and immediately heard a tape issue: the first note’s on pitch, then a weird “wow” in which the pitch dips, as if the tape had been damaged – stretched? – then a return to normal. The episode lasts less than a second, but my goodness, what a sound to open the listening session!

Listening to the HDTT version immediately suggests that this is an old recording. First, there’s a slight resonance that lends an “aw” quality to the sound. I won’t make too much of this: while noticeable, the resonance is not too distracting – but it is there. In addition, lower notes from Segovia’s guitar sound considerably duller than the higher ones – but this is only partly, and perhaps not at all, an issue with the recording. One needs to remember that Segovia was a master instrumentalist and colorist: he is using this thumb to play those lower notes in counterpoint to the higher ones played with fingers and, in some cases, perhaps struck with fingernails, thus creating different voicings for different parts. (This is especially noticeable on tracks of music by Bach later on the album, as the music is more contrapuntal in nature.) One also needs to take account of the characteristics of Segovia’s instrument, the type of strings that he would have used, and his own technique. All in all, the more I listened, the more comfortable I felt that I was hearing tonal balance fairly close to what I would have heard in person, notwithstanding that resonance mentioned earlier.

The Decca recording engineers brought the microphones rather close; the tape technology available at the time probably made that advisable, if only to keep the signal to noise ratio high. The close mic placement leaves one wishing for a little more air around the sound, but the apparent size of the guitar remains natural. Decca’s approach is pretty consistent in the works throughout the album, even though the recordings may have been made at different times, so we don’t suddenly and jarringly jump from performance space to space. Meanwhile, the good news about the upfront presentation is that we can hear the subtle details of Segovia’s performance – and Segovia provides delectable details aplenty.

Turning to the Pavanas as they appear on the MCA disk, the most obvious point of contrast is that these reissues “civilize” the original recordings. Tonal balances are more tipped up, which at first sounds more natural, and there seems to be an attempt to put some distance between Segovia’s guitar and the listener. However, there are downsides to these changes. First, the MCA versions lean toward the dreaded “eight-feet-wide guitar” effect. Second, the de-emphasis of the bass end robs the lower registers of their power, thus obscuring the harmonic structure that should be present. Third, the enhanced treble emphasizes finger noises. All guitarists, classical and otherwise, produce finger noises – squeaks, if you will – as their fingers move on the strings of the instrument. In the HDTT transfers, these noises are audible but subdued, simply a natural part of the background. On the MCA disk, however, these same noises are far more obvious, to the point of being obnoxious. In fact, the finger noises were such as to suggest steel strings on the guitar. (I hope that no classical guitarists reading that last sentence fainted in horror….)

Overall, then, it is clear to me that the HDTT transfers provide a better listening experience. No, they are not perfect – but that brings us to the issue of availability. Simply finding this album – and many other Segovia recordings – is a challenge. If you are a classical guitar fan, and you want to hear the father of modern classical playing (as you should), and you don’t want to spend your time haunting second-hand record stores, just get the HDTT transfer and enjoy the closest thing to the original that we’re ever likely to have.

Bartok: Music for Strings, Percussion, and Celesta. Reiner/Chicago

In the review above, I had to elaborate on details and close comparisons to elucidate the virtues of the HDTT transfer of the Segovia album. Now I get to relax: my job is way easier with the recording here. The performance is universally recognized as great, perhaps definitive. As we shall see, it’s also an easy call in favor of the HDTT transfer.

In keeping with my “easy job,” I do not have much to say about the Reiner/Chicago performance, not because the performance is unworthy of description, but because everything that I might write already has been written, and likely written multiple times. Suffice it to say that Bartok and Reiner were friends who surely communicated deeply about this music, and it showed in the performance. Moreover, the RCA recording team, with producer Richard Mohr and the legendary engineer Lewis Layton, was at the top of its game in this era, producing recordings that even today are considered masterpieces. That praise applies especially to the recordings of the Chicago Symphony under Fritz Reiner, and this recording, made in 1958, is perhaps one of their best.

On to the second easy part of my easy job. As with other RCA classics, this performance has been released in a variety of formats and combinations in the CD era. I have a copy from the 1990’s in which the coupling is Bartok’s Concerto for Orchestra. That will serve as my standard of comparison for the HDTT transfer, but I also was able to stream the same performance from a few other albums (thank you Idagio and Qobuz); so far as I could tell in quick comparisons, these latter versions all were identical to the aforementioned CD.

We can go right to bottom line: the HDTT transfer wins. In this case, despite the age of the recording, there are no issues with obnoxious balance or weird tape noises. Granted, at what we might call a “sonic glance,” the HDTT version sounds rather like the CD: sonic qualities such as the overall tonal balance, the perspective on the orchestra, the noise level (very low), and so on initially sound similar. But even a short listen reveals that the HDTT version has more depth, with clearer placement of instruments, than the RCA CD. The result is a more natural, realistic sound.

I could drone on for a while, but to what end? The performance is a must-have for anyone interested in this music, and the HDTT transfer just sounds better than the easily available CD. To put this in perspective: the original RCA recording is so good that the “standard” CD does sound quite lovely when considered on its own. If I had never heard the HDTT transfer, I could have lived happily with the CD. But the fact is that I did hear the HDTT transfer and now I’m spoiled. The differences are, in the great scheme of thing, subtle, but differences there are, and to my ears the HDTT version just sounds better.

What’s the Difference?
The question remains as to what is responsible for the superiority of the two HDTT transfers that I auditioned as compared to the major label CDs. Is it the transfer or the high resolution?

As mentioned earlier, John Puccio has noted the superior sound of several HDTT transfers at CD resolution as compared to major label CDs, thus suggesting that the careful transfers themselves have a significant effect even when playback is at the same resolution. Looking further afield, various sources in audioland sing the praises of high resolution, and the HDTT folks certainly feel that the higher resolution versions sound more like the analog originals. Then again, dissenting voices claim that it is very difficult in practice to hear differences between CD and higher resolutions.

But we’re really asking the wrong question: It’s not whether someone can hear the difference, it’s whether you can hear the difference – given the limitations of your audio system and of your hearing – and, if so, whether it’s worth paying extra for that difference. Fortunately, you can easily answer this question for yourself. Order the Bartok / Reiner / Chicago performance reviewed here in the highest resolution that your system will support, then spend a few extra bucks and buy the HDTT CD of the same performance. (You can even buy the budget CD with no box; you just need it for testing). Listen to them both: take your time, I’ll wait. Can you hear a difference, and does the difference justify the extra expense? Congratulations. You’ve just found the best sound available! No difference, or not enough to justify a higher price? Congratulations. You’ve just found great sound and saved some cash!

BH

[1]. I can’t resist this tidbit: a number of the British Invasion rock bands of the early to mid 60’s, including the Rolling Stones, were on the Decca label in Britain – London Records in the US – with their album covers proudly displaying the ffrr logo. Seeing a thumbnail promo on the paper record sleeve for, say, the Rolling Stones right next to one for Andres Segovia was, to say the least, interesting.

To listen to samples of these HDTT products, here are links to the HDTT Web site:

Segovia:  https://www.highdeftapetransfers.com/products/the-unique-art-of-andres-segovia?_pos=175&_sid=cdeb14039&_ss=r

Bartok:  https://www.highdeftapetransfers.com/products/bartok-music-for-strings-percussion-and-celesta-hungarian-sketches-fritz-reiner-chicago-symphony-pure-dsd?_pos=12&_sid=07452629f&_ss=r

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Handel: Concerti Grossi, Op. 3 (SACD review)

Georg Kallweit, Akademie fur Alte Musik Berlin. Pentatone PTC 5186 776.

By John J. Puccio

If you enjoy music of the Baroque and Classical ages played with elegance and refinement in historically informed performances, you might just like the Akademie fur Alte Musik Berlin, a German, period-instrument ensemble formed in 1982 that plays with a smooth precision and style. While they may not display the abandon of, say, Le Concert des Nations or Europa Galante nor with the sheer joy of the Philharmonia Baroque, the Akademie make up for it with the effortless polish of professionals who know and love their business and aren’t afraid of showing a little restraint in the process.

This is not to suggest, however, that the Akademie fur Alte Musik are in any way dull or commonplace. Far from it, as these performances of Handel’s Op. 3 concertos demonstrate. The concertos are clear, focused, and meticulously presented in interpretations both lively and graceful. It’s a refreshing combination.

Anyway, the German-born Baroque composer George Frideric Handel (1685-1759) wrote his six Concerti Grossi, Op. 3 sometime before 1734, when English music publisher John Walsh assembled them from earlier Handel works. Apparently, Handel himself had no intention when he wrote them of their becoming a “set,” nor did he have any idea beforehand what Walsh was up to with them. But have them we do. What’s more, they aren’t “concertos” in the modern sense at all, but rather they are mostly collections of overtures, fugues, dances, and the like arranged into suites of anywhere from two to five movements each. Handel did not design any of them to highlight individual instruments, either, or even to contrast different sections of the orchestra as do most traditional concerti grossi. But Walsh, wanting to capitalize on the popularity of concerti sets of the day compiled them from whatever bits and pieces of Handel’s music he could find. No matter. Much of it remains charming.

Of course, Handel admirers coming to this music for the first time and expecting to find another set of Water Music suites may be disappointed. There just isn’t the abundance of memorable tunes involved. Instead, we have mainly bits and pieces of Handel kind of thrown together to sell copies of the scores. And, of course, listeners not already familiar with Handel’s music may not care one way or the other because it probably all sounds alike to them anyway. But that is not to say there isn’t a lot to appreciate in the Akademie’s view of things, and I rather enjoyed some of “the bits and pieces.”

Maestro Kallweit and the Akademie play with a refined sensibility, somewhat understated on occasion but lively and brisk at other times. The first of the six concertos makes a good example of this. There are three movements to it: fast, slow, fast. And there is no doubting which is which because the fast movements sparkle with energy, while the slow movement, the Largo, is meaningfully leisurely.

Of the concertos I liked best, No. 2 is probably my favorite. It’s one of the longest at five movements, and each of the sections is clearly distinctive from the rest. Musical scholars have suggested that Handel may have written the whole thing as an overture; who knows. It certainly has all the earmarks of a curtain raiser and may easily be savored as a stand-alone item.

And so it goes. Nos. 3 and 5 both open with Largos, making them a bit different. However, the movements are generally so brief, it’s hard to notice. No. 4 seems the most grandiose, No. 5 the most grave. No. 6, the final concerto, seems almost an afterthought. It has only two movements, and it seems that the publisher simply wanted a concluding sixth work in the set because that was the fashion of the times. In any case, it is distinguished by an organ part in the last movement that foreshadows Handel’s later, more-developed organ concertos.

Producers Renaud Loranger and Karel Bruggeman and engineer Jean-Marie Geijsen recorded the concerti at the Nikodemuskirche, Berlin in May 2019. They made it in hybrid SACD, and I listened in SACD two-channel stereo. There’s more ambient bloom in the auditorium than we normally here, making the relatively small ensemble appear bigger than it is. It is not unpleasant. Otherwise, the sound is smooth and agreeable. You might even be hard pressed to tell it’s a period band and not a modern chamber orchestra because of the polished sheen of the sonics. It’s also a tad close, with only moderate depth. Nevertheless, it’s all quite listenable.

JJP

To listen to a brief excerpt from this album, click below:

On Rational Selection–Part I…

By Bryan Geyer

It’s nice to assess the quality and capability of a new power amplifier in advance of buying it; however, don’t expect to fulfill that research solely by listening. A listening trial will reveal almost nothing about the amplifier’s performance compatibility. You simply won’t hear insufficient voltage gain, or hear the loss that accrues from a poor impedance match. Lots of critical factors can be deficient, or significantly less-than-optimum, without imparting any audible evidence. In truth, it’s not even possible to detect, by ear, whether your test amplifier has sufficient power output capability. (A power amplifier should be capable of providing some +2dB to +3dB more undistorted power output than your loudspeakers can safely handle; refer commentary herein. That value can then be precisely determined by reference to the related product specifications.)

A solid-state power amplifier’s sonic character is almost entirely defined by the intervening physical and emotional filters that separate the listener’s aural perception from the amplifier’s output. Notable intervening screens include the loudspeaker system’s crossover network, the fidelity and character of the drivers , the acoustical nuance of the listening environs, and the shifting vagaries of your own personal mood. Most especially, the final sound will be the result of preconceived expectation; i.e., what your mind says you will hear. These compound and complex factors will cloud the aural linkage between you and the output of that new power amplifier. Any impression or conclusion that you extract will forever remain the product of this imprecise and subjective exposure. In essence, this is why listening is not an accurate or reliable way to appraise audio equipment. Do seek more rational options.

Audio component evaluation is best accomplished by research and inspection rather than by listening. You can pretty well determine everything that you need to know about a given component (let’s assume a power amplifier), by proceeding through the four steps listed below. The data is freely available; you just have to become conversant with how to utilize it effectively. Doing so will certainly require more commitment than passive listening, but it’s likely to be less taxing than interpreting all of the frothy adjectives that you see in a Stereophile product review.

(1)  Check for published reviews on the product. Focus on the factual test data + photos, and the related technical commentary. Skip over the author’s tiresome aural assessment; it’s pretentious nonsense. The Audioholics website is generally more useful than most because they excel on the tech stuff and minimize such fluff as “has expansive soundstaging, explosive dynamics, and exceptional transparency”, or claims that “it produces natural transient attacks, a generous, almost tube-like sustain, and take-your-breath-away decays that produce the sensation of floating on a cloud.” (These latter phrases were as extracted from an on-line Stereophile product review.)

(2)  Examine a photo of the amplifier’s back panel; it’s often available on the maker’s website, or in a published review. (Interior photos sometimes turn up as well. They can be informative too, but only if you already know a lot about what you see.) The back panel photo will give you a good grasp of the various input/output options and the connector detail, plus such features as the turn-on options, provisions for line level input trimming, bridged mono operation, and an understanding of how the line cord connection is implemented, and how the cord is dressed. This latter information is useful if you intend to substitute a replacement line cord; refer footnote.*

(3)  Briefly consider price, then size, then appearance. Eliminate the Dan D’Agostino ilk first. Gaudy products with preposterous prices are obsession traps. Don’t get snared; just move on. Review product size next. Nothing needs technical analysis if it won’t fit within the space allotted. Ditto if it exhibits a pretentious blue-glow-bloat and says McIntosh. Mac’s products just don’t fit my concept of contemporary design; they look more like archived relics from the 1939-’40 NY World’s Fair. Of course, you might disagree, but do reject, up front, all of the equipment that you feel presents undesired esthetics. Appearance matters—especially if it sports a prominent display panel.

(4)  Last, conduct a patient technical assessment of the pertinent performance specifications. Some of the more critical parameters that apply to power amplifiers follow, with comment about how the specification can affect operation. The primary objective is to select an amplifier that will perform in a manner that’s fully compatible and complementary when it’s integrated with your existing components, so you should also be well acquainted with their operating characteristics as well; review those specs too. Lots of this detail will become more apparent as we get into the individual parameters, so let’s begin now with…

INPUT IMPEDANCE (Zin): Whatever the value, assure that the noted Zin is consistent with what fits your need. Explanation: In audio electronics, effective (lossless) signal transfer requires that a low source (output) impedance (Zout) should feed into a much higher load (input) impedance (Zin). Of course, these low/high terms are relative, so their absolute value is flexible. If a preamp exhibits an output impedance of 50 to 100 Ω, that’s low, so almost any load impedance ≥ 10kΩ is then high enough. But if the Zout climbs as much as 2.5kΩ (as with a passive preamp using a 10kΩ attenuator), you’ll then want the load to be some 30kΩ to 50kΩ or higher. In general, when considering a power amplifier, don’t settle for anything with Zin < 30kΩ because you’d start to limit your source options. And yes, some hi-end power amplifiers actually exhibit Zin as low as 10kΩ.

OUTPUT IMPEDANCE (Zout): Low is desirable; higher Zout can breed issues. But how low/high? Well, it depends on what you’ve got. If it’s a solid state preamp, its implicit Zout of 50 to 100Ω is always fine. A vacuum tube preamp (typical Zout ≈ 400 to 500Ω) might be low enough too, if the ensuing load impedance is high enough (10kΩ) to prevent any significant interactive loss. A load impedance (Zin) that’s some 10X to 20X the source impedance (Zout) is a good guideline, so a really low Zout provides more freedom with respect to what might later constitute an acceptable load. When this ratio can’t be conveniently satisfied, an active unity gain buffer (UGB) stage can be inserted. The UGB is designed to provide a relatively high Zin (say ≥ 75kΩ), and a very low (50Ω) Zout, so that it can serve as an idealized “brick wall” to isolate some interim stage that has a higher-than-optimal output impedance; e.g., a passive preamp using a 25kΩ attenuator (worst case Zout ≈ 6.3kΩ).

BRIEF DIY ASIDE: If you’re a competent electronics buff with elementary circuit design smarts, you can create and construct your own very capable UGB, just as I and many others have done. Refer my paper headed “On Noise, Coax, and Control” for tutorial guidance on DIY UGB circuit design. The requisite semiconductors, passive components, connectors, and suitable through-hole stripboard stock (https://www.mouser.com/datasheet/2/58/BPS-DAT-(ST6U)-Datasheet-1282874.pdf) are readily available, at reasonable cost, from Mouser Electronics (https://www.mouser.com). And here…https://goldpt.com/enclosures.html…are two very elegant mini-box enclosures** that have internal support rails compatible with mounting the designated ST6U (1/16 inch thick) stripboard stock. Cutting that glass/epoxy (tougher than phenolic resin) stripboard to the desired size is best done with a portable Milwaukee M12-series saw (https://www.homedepot.com/p/Milwaukee-M12-FUEL-12-Volt-3-in-Lithium-Ion-Brushless-Cordless-Cut-Off-Saw-Tool-Only-2522-20/305663849), and the related abrasive cut-off wheel (https://www.homedepot.com/p/Milwaukee-3-in-Metal-Cut-Off-Wheel-3-Pack-49-94-3000/306599198).

BACK TO OUTPUT IMPEDANCE: Power amplifiers represent a dramatic example of the implicit advantage of low output impedance. A solid-state power amplifier will exhibit a Zout that’s naturally very close to zero; i.e. it’s generally ≤ 0.1Ω. That value will assure an ideal damping factor (≥ 100) and virtually no response-altering interaction with the loudspeaker load. As a result, the sonic character of the output will be shaped almost exclusively by the loudspeaker components alone, without related nuance traceable to the driving amplifier. Conversely, a vacuum tube power amp will exhibit a much higher Zout (> 20X higher) because its transformer-linked load interface is incapable of better coupling. As a result, the tube amplifier will directly interact with its speaker load (the Zout and Zin values will be of similar order) to create a unique “sonic signature” that can vary from the speaker’s natural voice. The higher Zout will similarly degrade the tube amp’s potential damping factor. (NOTE: Benchmark Media Systems offers a white paper concerning the importance of high damping factor; refer https://benchmarkmedia.com/blogs/application_notes/audio-myth-damping-factor-isnt-much-of-a-factor.)

POWER OUTPUT: This is the highlight specification for power amplifiers. First, verify that the stated watts are measured according to the industry standard code; namely that they reflect Volts rms (root mean square), not peak volts, and that a specific load is noted (e.g., 8Ω), and that the bandwidth extends from 20Hz to 20kHz. Obviously, more Watts = more power, and more power output is always good. The power output rating should also be listed for 4Ω loads too, and the closer that 4Ω rating gets to = 2X whatever power was listed for 8Ω, the better. Amps that can’t come within ≥ 85% of doubling their 8 Ohm power rating when full output is applied across a 4 Ohm load might be a bit current-limited; maybe too wimpy to meet the peak dynamic transients in Respighi’s Pines of Rome when it’s played at sound pressure levels approaching 90dB (C-scale weighted).

Always assure that your amplifier’s full power output capability is at least some +2dB (1.6X) to +3dB (2X) > the rated power that your loudspeaker system can safely tolerate. This will assure that the loudspeakers are never exposed to a clipped input signal when driven to levels that are within their rated maximum power limit. Outside of physical abuse, nothing can be more potentially injurious to a loudspeaker system than consistently clipped drive signals, and nothing sounds worse than peak level clipping.

VOLTAGE GAIN: This is an important parameter that’s often overlooked. Power amplifiers typically exhibit different voltage gains. They generally vary between ~ +23dB and +30dB, with most of them ranging between +26dB and +29dB. This is an intrinsic design parameter, not the consequence of random variance, so it’s an important user consideration, and it deserves your attention.† The actual gain, expressed in dB, may not appear as a listed spec, but you can readily derive it from the published “input sensitivity” spec. Just do the math: P = EE/R, where P is the power in Watts, E is the AC signal in Vrms†† (EE = E-squared), and R is the load resistance in Ohms. A power amplifier that requires 1.0Vrms to produce 100 Watts into an 8Ω load has a voltage gain = 28.28X; otherwise expressed as +29dB.*†

INPUT SENSITIVITY: Is simply a measure of the input voltage needed to drive a power amplifier to a specified output level (generally, but not necessarily, to full output). It’s precisely the same parameter as voltage gain (above); it’s just restated after somebody else does the math. The “input sensitivity” is = 1.0Vrms when it drives the same amplifier to 100 Watts output across that 8Ω load.

The term “input sensitivity” brings to mind a fundamental concern: You want to assure that your power amplifier has sufficient internal gain that source signals, at their highest levels, are sufficient to drive your power amplifier to full output when your volume control is at zero cut (volume full up). Of course, if you’re using an active preamplifier between your source and the power amplifier, then copious extra gain—likely some +8dB to +12dB, and maybe even more—is available, with virtually all of it unneeded. However, in the event that you’ve modernized your system to eliminate that superfluous high level gain stage, then do assure that your CD player’s output, when driven at the maximum standard 0dB record level, is sufficient to push your power amplifier to full output when volume is set at zero cut. Let’s take an example: My own CD player (a discontinued Onkyo C-7000R) puts out ≈ 1.98Vrms (let’s say 2Vrms) across my 20kΩ volume control when driven at the industry standard 0dB maximum recording level (at 1kHz), and the channels match to within 0.2dB. I’m confident that your CD player’s output will be very close to same. (A good quality CD test disc with 0dB record levels at 1kHz [actually 1.001kHz for some obscure reason] is easily purchased. Mine is “Denon Audio Technical CD” #38C39-7147, and the 0dB test tones are on bands #18 [left] and #19 [right]. This is a professional grade test disc from 1984; it’s now scarce, but sometimes pops up on Amazon. Equivalents are commonly available. Boston Audio Society member DB Systems lists a compendium of test CDs at http://www.bostonaudiosociety.org/db_systems.htm.)

My power amplifier (a Parasound A23, circa 2014, now superseded by A23+) has a voltage gain = +29dB, and the specified full output is 125 Watts/channel into an 8Ω load. As a result, I can be certain that a CD source signal of 2.0Vrms will be more than sufficient to drive my amp to full output. How do I know that? Well, 125 Watts into an 8Ω load means that there’s 31.6 Volts of source signal impressed across that load. Subtracting 29dB of gain (0.035 x 31.6Vrms) tells me that the input need be only 1.1Vrms to drive my amp to full output. So I’d have a full 0.9 Volt margin relative to the potential 2.0Vrms input. (The volume control serves to prevent input > 1.1Vrms, hence avoid clipping.) OK, but what if my power amp had only +23dB of voltage gain instead of +29dB? Well, with volume then turned full up (zero cut), that would mean that the amp would need 0.071 x 31.6Vrms = 2.2Vrms input to reach 125 Watts into 8 Ohms. With just 2.0Vrms of drive from the CD player I’d be close, but still some -0.9dB short of the 2.2Vrms minimum required to produce 125 Watts across 8 Ohms.

The implication is clear: Pay attention to a power amplifier’s voltage gain specification. Be certain that your power amp can always reach its fully rated output (regardless of what that output might be) when your CD player hits the highest signal level that the CD recording process permits; i.e., the 0dB record level. Here is a summary of the recommended amplifier gain consistent with stated output levels, assuming an 8Ω load and a CD player that puts out ~ 2.0Vrms when fed at the standard 0dB maximum record level.
 
            +26dB minimum amplifier voltage gain when rated output is ≤ 200 Watts.
            +27dB minimum amplifier voltage gain when rated output is ≤ 250 Watts.
            +28dB minimum amplifier voltage gain when rated output is ≤ 300 Watts.
            +28.5dB minimum amplifier voltage gain when rated output is ≤ 350 Watts.
 
These minimum gains assure that a 2.0V input signal will drive the power amplifier to the cited output. More gain is fine, but only up to a point. Hold amplifier gain to +31dB or +32dB tops. If your gain was any higher you’d then be forced to unduly retard your volume control setting (to the 9 o’clock arc) when listening at more moderate levels, and that’s not good either. Indeed, that would replicate the penalty that you accept when retaining a conventional active preamp. The preamp’s high level boost of some +8dB to +12dB is grossly excessive, and that unwanted excess prevents good volume management. Dump that archaic active preamp! Instead, get a passive equivalent, and buy (or build) a better volume attenuator than the $15 Alps RK271-series dual pot that’s inside most of the hi-end active preamps.

My own DIY 20kΩ stereo volume control uses a stepped 24 position double-deck switch (Goldpoint type V24C-2, see https://goldpt.com/compare.html), with 23 fixed ±0.1% tolerance metal-film (low noise) 1/4 Watt resistors per channel (46 total), all carefully hand-soldered in position. It provides precisely -2dB-per-step attenuation over 70% of its full -60dB span, and its calibrated ±0.1% accuracy assures far better channel tracking than the crummy 2dB or 3dB ∆ that’s specified for premium Alps pots.

That’s quite enough for this session. In the next paper we’ll continue with this same subject, and discuss some additional parameters that you should review when perusing power amplifier specifications.

BG (September 16, 2020)

*There are often good reasons to seek a replacement line cord. You might need a shorter or longer cord, or one with an angled (90˚) socket, to reduce the rear clearance. And you might choose to utilize a 14 AWG line cord instead of the supplied 16 AWG cord. (Don’t consider 8-10-12 AWG cordage. There is no electrical benefit, and fatter gauge power cords become difficult to route.) USA market amplifiers utilize a molded SJT-type cord, with a Nema 5-15P plug and a IEC320 C13 socket (C13L or C13R if it’s angled). Simply order a replacement (molded, SJT grade, 14 AWG) cord of the length that you want, with socket and plug as desired. This site-- https://www.pchcables.com/expocoandad.html--offers many existing stocked options at very reasonable prices, and the quality is excellent. This site…https://www.stayonline.com/cordbuilder/molded-cord-configurator.asp…will custom-build your cord to your own personal specifications. Just fill in the options on the form; pop-up photos will guide you in making your selection.

Ignore all chatter about ultra-costly replacement line cords that allegedly improve the sound of an amplifier. That fable traces to a pervasive human weakness that we know as confirmation bias (https://en.wikipedia.org/wiki/Confirmation_bias). The effect is persuasive, and groupthink-infused (https://en.wikipedia.org/wiki/Groupthink) zombies on sponsored websites keep this promotion pumped—as do the retail dealers. Upgraded line cords are among the most profitable of all products stocked. Sales are good, and returns (sometimes not permitted until a mandatory “burn-in” cycle has elapsed) are easily resold. Here is an array…https://www.thecableco.com/cables/power-cables.html?limit=all…of 318 assorted line cords for sale; prices range from ~ $100 to $12,000 each. Of course, science says that the mythical emperor still has no clothes. A substitute line cord will produce no audible change, at least not until some other user says “Hey, can’t you hear that tighter definition in the mids?”

**The Goldpoint #EN1-C enclosure size is quite sufficient if you’re content with using standard metallized polyester film input and output coupling capacitors. However, if you’re going to use premium Vishay MKP 1848 series polypropylene coupling capacitors (they’re big!) you’d need the slightly wider Goldpoint EN2-C enclosure.

†When comparing different power amplifiers in a listening trial, don’t expect to freeze the volume control at some fixed position and assume that you’re thereby providing a fair comparison. The amp with the higher gain will always win, even when decidedly inferior. A difference of just 1dB is enough to sway all votes.

††Use of the designator “E” to represent voltage stems from the classic tutorial use of the term “electromotive force” to describe the voltage function. It’s akin to pressure when expressed as a plumbing analogy.

*†Do keep a “Decibel Table” handy, and review how to read it. Here’s an on-line pdf copy of the “Handbook of Electronics Tables and Formulas”, 6th edition (1988); refer decibel table, pp. 32 to 36…
https://redcxem.ru/files/Handbook_of_Electronics_Tables_and_Formulas.6-th_ed.1986.pdf.
Especially note the scaling difference between voltage gain or loss and power gain or loss. A voltage gain of 2X = +6dB, whereas a power gain of 2X = +3dB.

Telemann: The Colourful Telemann (CD review)

Barthold Kuijken, Indianapolis Baroque Orchestra. Naxos 8.573900.

This is only a guess, but I’d say if you asked almost any casual classical-music listeners to name their favorite Baroque composers, they’d probably respond with Bach, Handel, or Vivaldi. So why does the German Baroque composer Georg Philipp Telemann (1681-1767) get less love than these other fellows? Maybe it’s because he didn’t write a set of Brandenburg Concertos or Water Music or Messiah or 800 variations on “The Four Seasons.” People tend to remember someone’s greatest hits, and, face it, Telemann didn’t have a lot of greatest hits.

Nevertheless, Telemann was among the most prominent composers of his day and was at least as famous in his time as his personal friends Bach and Handel. What’s more, he was at least as prolific, if not more so, than his celebrated contemporaries. The album under review, “The Colourful Telemann,” contains five of his more vibrant, spirited yet relaxed, picturesque, and convivial tunes.

The performers are a comparatively recent period-instruments orchestra, the Indianapolis Baroque (or IndyBaroque), formed in 1997 and led by flautist and recorder player Barthold Kuijken, whom you may know from his work with brothers Wieland and Sigiswald Kuijken in La Petite Bande. The Indy ensemble are good and serve the music with skill and high spirits.

First up is the Ouverture in C minor. Here we find Telemann at his most unhurried, and Kuijken seems perfectly content with playing it that way. There is nothing forced, rushed, or driven about the performance. Instead, it’s a little like a Frederick Delius piece, maybe a casual boat ride one summer evening. Still, Kuijken moves it along at a graceful, stately gait, ensurng it doesn’t become stodgy.

Next is the three-movement Concerto for Two Flutes in G major, where Kuijken shares the baroque transverse flute solos with Leela Breithaupt. Again, we get a relaxed Telemann, his inspirations French, Italian, and even Polish in the final presto. The playing is refined and elegant.

After that is the five-movement Sonata in E minor, which is perhaps a shade more solemn than the previous selections. Nevertheless, Kuijken moves it along at a fluid, gracious pace, the concluding movement, marked “Gay” a special delight.

Then, there is the four-movement Concerto for Two Flutes, Violin and Cello in D major, which seems to include parts for just about everyone in the ensemble. You may notice here a certain degree of similarity with Bach’s Brandenburgs, partly in the layout of instruments and multiple soloists and partly in the tunes themselves. Kuijken leads the players with a slightly yet subdued tone.

The program ends with the seven-movement Sinfonia Melodica in C major, which may have been among Telemann’s final compositions before he died. If so, he went out in style. It’s a delightful, affable, and courtly farewell.

Producer, engineer, and editor Malcolm Bruno made the recording at Ruth Lilly Performance Hall, Christel DeHaan Fine Arts Center, University of Indianapolis in February 2019. The sound is a tad sharper and clearer than we usually hear from Naxos. For the most part, it’s quite natural, with a smooth, rounded midrange and a nicely extended high end. The lower treble is sometimes prominent, but it is never distractingly bright. The lower end of the musical spectrum is somewhat wanting, however, and dynamics are average at best.

JJP

To listen to a brief except from this album, click below:

Vaughan Williams: Symphony No. 5 (SACD review)

Also, Finzi: Concerto for Clarinet and Strings. Michael Collins (clarinet and conductor), Philharmonia Orchestra. BIS-2367 SACD.

By Karl W. Nehring

I strongly suspect I am not alone when I say that Ralph Vaughan Williams ((1872-1958) is one of my favorite composers and that his Symphony No. 5 (1938-43) is not merely one of my favorites among his compositions, it is one of my favorite compositions, period. Somewhere around 40 years ago, I was even fortunate enough to attend a live performance of the work by the Ohio State University student orchestra. I currently own three boxed CD sets of RVW’s symphonies (Haitink, Previn, and Slatkin) plus several individual  CDs of Symphony No. 5 (Previn – on both RCA and Telarc, Boult, Slatkin, Spano, and Hickox). This new BIS release conducted by noted British clarinet virtuoso Michael Collins has nothing to be ashamed of in this heady company. It is definitely a keeper – and for several reasons.

The opening Preludio is a haunting movement, one that just seems to float along with majestic motion, like a river flowing along in a beautiful natural setting, or clouds moving through the sky on a gorgeous summer day. Although the overall mood is pastoral, there are moments when the listener can sense an underlying tension. Collins conducts this music with a subtle flexibility of pace and tempo that enhances the shifts in mood without overtly highlighting them. He moves briskly through the next movement, Scherzo, which maintains a pastoral sound but with a restlessness that seems to represent an unsettled or troubled mind seeking some form of resolution, or at least consolation.

The third movement, Romanza, incorporates musical ideas from RVW’s setting of John Bunyan’s The Pilgrim’s Progress. (I actually attended a performance as an undergraduate back in 1969, but remember virtually nothing about it. And no, I was not high – contrary to the 60s stereotypes – I just really do not remember anything about the music.) After the nervous energy of the Scherzo, the calm but emotionally, even spiritually resonant music provides succor and inspiration to the soul. There are passages of great delicacy as well as moments of measured intensity that are played with expressive power under Collins’s baton. This is music of great power, but it is restrained power, purposeful power. It clearly shows the genius of Ralph Vaughan Williams, a great composer by any measure.

The final movement, Passacaglia, moves along with measured purpose, the music no longer floating along as in the first movement, but with a sense of coming to the end of a memorable journey. Collins again adapts a subtly flexible approach to tempo and volume that serves the music well. The two recordings that I generally listen to when the mood strikes me to hear this symphony have been the two Telarcs, Previn and Spanos. I believe that duo is now a trio.

The other work on this SACD release (I listened to the stereo SACD layer; there are also SACD surround and CD layers) is the Concerto for Clarinet and Strings by Gerald Finzi (1901-1956), who was a friend and admirer of RVW. Finzi is most well-known for his vocal works, but he also wrote some beautiful instrumental music.

Michael Collins

The opening measures of the Concerto feature dramatic decorations by the strings, which are then joined by much more lyrical lines from Collins’s clarinet. As the movement continues, the overall sensation is peaceful and pastoral, gentle and beautiful. Around the 7-minute mark, Collins delights with a solo cadenza that is startling in its emotional impact. The second movement sustains that pastoral mood, opening quietly in the high strings and with introspective, even reverential playing from Collins on the clarinet. Even more so than the opening movement, this is music very much in the English pastoral tradition. About two-thirds of the way through, the tempo and overall energy level pick up for a spell, but then things calm back down, the movement ending quietly. The final movement is considerably livelier and more energetic. Whereas the first two movements were quiet reflections on nature, taking the listener out into the meadows and fields, this final movement takes the listener for a merry imaginary jaunt down a country road, still in nature, but observing at a more determined pace, perhaps heading home with renewed energy and enthusiasm for life.

The engineering on this release is first-rate, from a team led by veteran soundsmith Mike Hatch. The orchestra sounds balanced, with not a trace of harshness to be heard. In the Concerto, the balance between clarinet and orchestra is just right, without the too-close miking of the soloist that would have exaggerated the perceived sonic size of his instrument. Although the liner notes (in English, German, and French) are not particularly expansive in scope, they do provide a helpful overview of the music. With more than 68 minutes of music, the disc is generously filled. One final item note about the physical package is that the disc is enclosed in a paper sleeve, a miniature version of the sleeves that cover vinyl records. Thank you, BIS, for this extra layer of protection!

As I noted above, this new recording of the RVW Symphony No. 5 is a very worthy addition to a crowded field. In addition to the fine performance and sound, and added attraction of this release is the delightful Finzi Clarinet Concerto. Indeed, most releases of the RVW Symphony No. 5 with another RVW symphony or some of his other works. That is all well and good, as just about anything composed by RVW is well worth hearing, but the music of Finzi is generally not nearly as familiar to many music lovers, meaning that this release might well serve to introduce this composer to folks who will then be inspired to seek out other music that they might otherwise have never heard. You can’t go wrong there, folks. Let your Finzi freak flag fly!

KWN

To listen to a brief excerpt from this album, click below:

 

Rodrigo: Concierto de Aranjuez (CD review)

Also, Ponce: Concierto del sur; Garcia: China Sings! Junhong Kuang, guitar; Darrell Ang, Czech Chamber Philharmonic Orchestra. Naxos 8.579053.

By John J. Puccio

First, the contenders: The first stereo recording I ever heard of Rodrigo’s famous guitar concerto was by Narciso Yepes on a 1957 London (Decca) LP. So I have a fond affection for it, especially now that HDTT have remastered it. Then there is an equally good (and old) stereo recording from Angel Romero on Mercury and a later one on EMI that are also quite good; plus entries from Carlos Bonell (Decca), several from John Williams (Sony), several more from Julian Bream (RCA), another from Sharon Isbin (Warner), and still another from Christopher Parkening (EMI). The list pretty much goes on and on.

Now for the new contender: Junhong Kuang, with Darrell Ang and the Czech Chamber Philharmonic on Naxos. There is stiff competition for him, but the performance and recording quality certainly hold up their part of the show. Junhong Kuang is a young (b. 1999) classical guitarist who has won any number of competitions over the past decade and performed with a variety of topflight orchestras. The Rodrigo marks his second recording for Naxos.

You may remember that Spanish composer and pianist Joaquin Rodrigo (1901-1999) wrote the Concierto de Aranjuez for guitar and orchestra in 1939, and it eventually established Rodrigo’s reputation as a leading composer for the classical guitar. I say “eventually” because it wasn’t until Yepes and Argenta recorded it in monaural in the late Forties that it really took off.

Rodrigo described the first movement Allegro con spirito as "animated by a rhythmic spirit and vigour without either of the two themes interrupting its relentless pace." Certainly, Kuang’s performance is spirited and animated. If anything, it appeared to me faster than most, which actually isn’t the case. It’s just that Kuang’s playing is so virtuosic, so dazzling, it sounds quicker than it really is. To be sure, Kuang is letter perfect (or note perfect) and remarkably precise, yet his remarkable precision loses a little something in nuance. I didn’t feel as affected by either of Kuang’s first two movement readings as I did with Yepes or the Romeros. In any case, under Kuang the first movement remains fun, and it’s assuredly lively.

Junhong Kuang

The composer said that the second movement "represents a dialogue between guitar and solo instruments” (cor anglais, bassoon, oboe, horn, etc.). What he didn’t say was how utterly beautiful it can be, something audiences have been saying for close to eighty years. Again, however, Kuang’s penchant for virtuosity works against him here more than anywhere else. I found his performance less sensitive than some of the aforementioned guitarists, although still graceful and lyrical enough.

Then there’s that perky little closing tune, the one Rodrigo said "recalls a courtly dance in which the combination of double and triple time maintains a taut tempo right to the closing bar." It seemed to me the best judged of the three movements Kuang recorded.

The couplings--Manuel Ponce’s Concierto del sur and Gerald Garcia’s China Sings--get the same treatment as the Rodrigo, with virtuosic playing from the soloist and warmhearted accompaniment from Ang and his Czech Chamber Orchestra. The Ponce work is almost as famous as the Rodrigo and charming, to be sure. The Garcia piece, dedicated to Kuang, is less Spanish in flavor than the others (two popular Chinese tunes were the inspiration) and played by Kuang with obvious affection.

Producer Kiri Stilec and engineer Vclav Roubal recorded the music at the Dukla House of Culture, Pardubice, Czech Republic in August 2019. You may recall that at one time the Decca record company was known for its “Decca Sound.” Perhaps we should label Naxos orchestral recordings as having a “Naxos Sound.” It’s slightly soft, yet fairly well detailed, and exceptionally big and widely spread out. The guitar is nicely articulated and realistically integrated with the orchestra, not too far out in front. Depth perception is somewhat limited, though, while dynamics are only moderate and the upper midrange can occasionally display some shrillness.

JJP

To listen to a brief excerpt from this album, click below:

Kaufmann: Chamber Works (CD Review)

Includes: String Quartet No.11; Sonata No. 2, Op. 44 for Violin and Piano; String Quartet No. 7; Sonatina No. 12 for Violin and Piano (arranged for clarinet and piano); Septet for Three Violins, Viola, Two Cellos, and Piano. ARC Ensemble (Erika Raun and Marie Berard, violins; Steven Dann, viola; Thomas Wiebe, cello; Joaquin Valdepenas, clarinet; Kevein Ahfat, piano) with Jamie Kruspe, violin, and Kimberly Jeong, cello (in the Septet). Chandos CHAN 20170.

By Karl W. Nehring

This new release from Chandos is the first commercial recording devoted to music by the Czech-born Jewish composer Walter Kaufmann (1907-1984). Not the first recording of these particular pieces, mind you, but the first commercial recording of any of Kaufmann’s music. All of the pieces on this release were composed between 1934 and 1946 when Kaufmann was a refugee in India, having fled Europe in response to the rise of National Socialism.

His story is a fascinating one. He was first taught music by his uncle, a violinist and music historian who ran a local music school. After graduating from his local school, he attended the Musikhochschule in Berlin, where he was introduced to the music of India, which was at that time largely unknown in Europe. The music sounded strange to him, but he was curious to learn more about it. While still in his early twenties he was an assistant to the famed conductor Bruno Walter, and some of his early compositions began to get some recognition from performances in Prague, Vienna, and Berlin. In 1927 he enrolled in the German University in Prague. He rented a room from Franz Kafka’s mother and eventually married one of Kafka’s nieces. While a student in Berlin, Kaufmann met and befriended an amateur violinist named Albert Einstein, whom he would accompany on the piano. The two remained friends until Einstein’s death. But with the rising threat of anti-Semitism in Europe, Kaufmann decided to get an Indian visa. He wound up staying there for 12 years. In 1946 he moved to Canada, then on to the United States in 1956, where he taught at the Indiana University School of Music for the remainder of his career.

Walter Kaufmann

The ARC Ensemble consists of senior faculty from the Royal Conservatory of Music’s Glenn Gould School in Toronto, Canada. They have made a specialty of recovering and recording music that has been suppressed and marginalized under the 20th century’s repressive political regimes, releasing a series of recordings under the heading of “Music in Exile” on the Chandos label, this being the fourth (the others featuring music by composers Paul Ben-Haim, Jerzy Fitelberg, and Szymon Laks).

The program opens with Kaufmann’s String Quartet No. 11, which consists of four movements. The listener can sense a non-Western undertone to the music, even though it also sounds clearly European in style. After the first movement comes to a close with an accelerando, the second movement evokes a softer, more plaintive mood, with a brief march-like interlude before coming to a quiet ending. The third movement opens energetically, with the music shifting to a more non-Western feeling again, with melodic figures running up and down with invigorating energy. The finale opens briskly, played with decisive flair. There is a strong rhythmic underpinning to this music, a driving pulse that can be felt as well as heard, winding down toward the end but then ending with a final flourish.

Next up is the Sonata No. 2 for Violin and Piano, which opens quietly with the piano in the lead, the violin then joining in with a yearning melody. As the movement continues, there is an element of Dvorak-like sound (Dvorak was also Czech, of course), ending with a frantic dash to the finish. The second movement is more somber, becoming tender and touching, a subdued and quiet flame that dims to a peaceful, subdued ending. The final movement, by contrast, opens with a start and sustains an energetic, dancelike motion culminating in an exuberant ending.

ARC Ensemble

The centerpiece of the album is Kaufmann’s String Quartet No. 7, which provides ample evidence that the composer truly had a knack and a feel for quartet writing. The movements display a variety of moods, from the opening movement with its energetic opening and oft-repeated four-note theme, the quieter but extremely beautiful second movement, the fleet third movement, the yearning fourth movement, all the way through to the finale, its whirling, dancing, up-tempo energy interwoven with a more stately second theme. This is truly an impressive string quartet.

The next piece, his Sonatina No. 12 for Violin and Piano, is presented here in an arrangement for clarinet and piano. The three short movements include the gently melodic first movement, a spritely and perky second movement, and a final movement that is softer in tone, exuding an atmosphere of happiness and contentment. (Oh, I’m a fool for a clarinet…)

Closing out the program is the one-movement Septet for Three Violins, Viola, Two Cellos, and Piano. Over its nearly 15-minute length it changes moods and sonorities, but tends for the most part to maintain a consistent pulse. There are moments of dance, movements of mystery, moments of reflection, and moments of song before the piece finally fades into peaceful silence as the program ends.

The sound quality on this recording is exemplary. Especially noteworthy is the sonic soundstage, which is stable and sized right, with no huge violins or other such anomalies such as sometimes emerge on recordings of chamber music. The liner notes present a wealth of information about Kaufmann, including a number of photographs of the composer at various stages in his life. With more than 77 minutes of music that has never been recorded before, this recording presents a compelling case that the music of Walter Kaufmann deserves to be heard. What other musical delights might be hidden away in the Kaufmann archives?  

KWN

To listen to a brief excerpt from this recording, click below:

 

Beethoven: Symphonies Nos. 1 & 2 (CD review)

Also, C.P.E. Bach: Symphonies Wq 175 & 183/4. Bernhard Forck, Akademie fur Alte Musik Berlin. Harmonia Mundi HMM 902420.

By John J. Puccio

If any of Beethoven’s major works benefit from being played by a period-instrument band following historically informed performance practices, it’s surely his first two symphonies. He wrote them, after all, with one foot still firmly planted in the Classical Period and the other foot starting to move in the direction of Romanticism.

The Akademie fur Alte Musik Berlin, under the guidance of concertmaster Bernhard Forck, give us performances that undoubtedly come close to what Beethoven might have wanted in his day, yet they are not rigid in their adherence to the composer’s famously controversial tempo markings. If we may take Roger Norrington’s recordings with the London Classical Players as a benchmark for following Beethoven almost to the letter, Forck’s interpretations are more relaxed, a minute or more slower than Norrington in all the fast movements. By comparison, Norrington may be more exacting but he also sounds more wooden, more concerned with playing the notes in proper speeds rather than letting the music flow more naturally as Forck does. In essence, Forck plays both of these first two Beethoven symphonies somewhere between the composer’s absolute tempos and what we hear from most traditional readings on modern instruments. It’s not a bad trade-off and works better here, I think, than in Forck’s recording of Beethoven’s Sixth Symphony, which I reviewed some months earlier, where the near-metronome tempos took away some of music’s charm.

Anyway, Beethoven wrote his Symphony No. 1 in C major in the late 1790’s, premiered it in 1800, and published it in 1801. It clearly shows the influence of two of the composer’s forerunners, Mozart and Haydn, yet it also shows traces of what was to come in his Third Symphony. That is, we see dissonance and contrast used more predominately than ever before. Maestro Forck doesn’t overemphasize these characteristics, but he does play with them enough to make the audience aware of their significance. While Forck may observe HIP standards, at the same time he recognizes that this music looks forward to the Romantic Age and, as occasion arises, he softens it a touch, “romanticizes” it, as it were. The result is a delight, some of the best early Beethoven you’ll find.

Bernhard Forck

Beethoven wrote the Symphony No. 2 in D major in 1801 or 1802 and premiered it in 1803 at a time when his deafness was getting worse, and almost incurable. Not everyone seemed to like the symphony in its day, one critic writing that it was like “a hideously writhing, wounded dragon that refuses to die, but writhing in its last agonies and, in the fourth movement, bleeding to death.” Harsh. Yet it wasn’t just in Beethoven’s time that the symphony got panned. Even more recently musicologist Robert Greenberg has written, “Beethoven's gastric problems, particularly in times of great stress--like the fall of 1802--were legendary. It has been understood almost since the day of its premiere that that is what this music is all about. Beethoven never refuted it; in fact, he must have encouraged it. Otherwise, how could such an interpretation become common coin? And common coin it is.”

“Gastric problems” or not, the music has survived the barbs nicely through the centuries, and Maestro Forck plays it with a lively, though never extreme, enthusiasm. It’s remarkable, too, that the orchestra, playing on period instruments, sound so effortlessly modern. There is none of the abrasive quality we sometimes hear in period orchestras. And the reduced size of the ensemble affords excellent transparency and immediacy. These performances are among those period-instrument/historically informed affairs that will appeal to folks who usually resist such things. The recording makes another fine addition to the catalogue.

Coupled with the Beethoven are two sinfonias (early symphonies) by Carl Philipp Emanuel Bach (1714-1788), written several decades before the Beethoven works and chosen, I would imagine, to point up the differences and similarities those few decades made in the development of orchestral music. Franck and his team play them with the same restrained ardor they display in the Beethoven, making them a light and airy listen. However, I didn’t much care for their positions on the disc, opening the program and then separating the two Beethoven symphonies. I would have preferred having them set apart on their own. Still, with a CD player one can play them in any order one chooses or disregard them altogether.

Artistic Director Rene Moller and sound engineer Tobias Lehmann recorded the symphonies at Teldex Studio Berlin in September 2018. The sound has a nice sense of presence, of left-right, back-front stereo spread. It’s also realistic in its frequency response and dynamics, but it never hits you over the head with anything unusual: no brightness, no edge, no dullness, no noise, no closeness.

Although there is nothing spectacular about the sound, everything seems just right for a smooth, pleasurable experience.

JJP

To listen to a brief excerpt from this album, click below:

On What’s Happening Now…

By Bryan Geyer

It’s clearly apparent (well, maybe not to those that cling to vacuum tube technology) that major change is ongoing in the design and configuration of home audio systems. Obviously, one of the hot trends involves the arrival of class D high power, high efficiency amplifiers—mostly as replacements for the classic A/B bias amps that have been dominant for ~ 70 years. The class D drift began a few years ago with the release of various new ICEpower and Hypex advanced class D high power amplifiers that were sold, in “open chassis” form, directly to the established OEMs (original equipment manufacturers) that make power amplifiers. The intent was that these traditional OEMs would add some proprietary peripheral content, mainly in the form of their own enclosures and preferred input/output terminations, and then market those class D amplifiers as their own finished product.

This course represents major change. All OEM participants that buy the same class D power amplifier module (complete with captive switch-mode power supply) would then be reselling the same basic product, as supplied from the same common source. Although their finished retail products would likely exhibit distinctive external shape/size/weight, and (maybe) sport unique in/out terminations and/or special peripheral features, they’d all use the same class D engine, hence offer the same native performance and same sonic signature.

The compelling benefit that drives this new marketing concept is high efficiency. A modern class D stereo power amplifier can deliver full power output to the load with efficiency on the order of some 86%. As a result, Class D bias can dramatically reduce internal waste (heating), and thereby eliminate much of the massive heat sinking that’s essential when operating in conventional class A/B (and class A) mode. The attendant saving in cost can be appreciable, and the related size reduction can be dramatic.

There’s nothing conceptually new about class D; it’s been around since the late 1950s. What is new is that a very talented and highly select coterie of creative audio engineers—largely concentrated in Denmark and The Netherlands—have now created new class D high power amplifiers that can deliver this high efficiency advantage without any of the attendant performance penalties that formerly plagued class D application. Finally, we have elegant, effective, and efficient class D stages that can output 300-400-600 Watts/channel without the noise and distortion artifacts that always limited this technology to a benign “yes, it’s interesting” reality. The key Danish and Dutch engineers responsible for this breakthrough currently represent three independent competitors: ICEpower and Purifi Audio, both located in Denmark, and Hypex Electronics in The Netherlands. These outfits are the principal innovators. Some other nearby companies are immersed in class D product development; e.g., Lyngdorf Audio, in Denmark, and Nord Acoustics, in the U.K. The latter offers a wide assortment of modular high power amplifiers (for OEM resale) that are exclusively based on the latest advanced class D products from Purifi Audio and Hypex Electronics. (Nord appears to be an authorized distributor.)

There’s also now a smaller new class D innovator here in the U.S.: Orchard Audio, of Succasunna, NJ, some 40 miles west of Manhattan. Orchard specializes in select class D power technology using gallium nitride (GaN) materials. GaN devices exhibit a higher operating temperature capability than conventional silicon semiconductors, so I presume that Orchard Audio’s unique offerings will be primarily optimized for non-consumer applications.

The engineers representing these key companies have been actively seeking a solution to the class D high power puzzle for more than a decade, but it has only been within the last few years that success seems assured. The class D challenge is demanding. Every step of the exacting process requires special expertise. Complex interactive design and assembly includes the necessity to identify, specify, obtain, and test unique semiconductors with select characteristics, as well as the use of special passive components like the novel LC filter inductors evident on every class D power amplifier PC board. At present, no manufacturer of high quality audio power amplifiers can replicate the excellence of the modular class D high power amplifiers available from these dominant Danish and Dutch providers. Indeed, nobody other than Orchard even comes close.

At present, various traditional OEM producers of power amplifiers buy these new modular class D amplifiers directly from the Danish and Dutch makers, or from their authorized distributors. These OEMs then add the requisite housing and input/output interfacing, plus maybe some peripheral features, and market the composite package under their own trade label. That course has now proved feasible for several well known U.S. participants that traditionally sold class A/B bias power amps of their own design. Marketing proprietary product that’s been created and provided by an outside sole-source patent-holder is a new endeavor for most of these established OEMs. This sort of selling is probably common in the overall scope of worldwide consumer electronics, but it’s new and novel in the more restricted confines of the hi-end audio power amplifier business.

The ICEpower 700AS2 amplifier module is a good example of how this cooperative concept can succeed, at least for ICEpower and for the consumers that ultimately acquire their product. The traditional OEM houses that currently buy, repackage, and resell these advanced class D power amplifiers might feel conflicted about this new means of serving their primary market, but they really have no other choice. There’s now a hot demand for top quality class D high power technology, and the only way that these OEMs can serve that need is to ship the existing Danish and Dutch product—it’s their only way to remain relevant.*

Within the past 4 years, several prominent U.S. producers of power amplifiers have released new class D amps that feature the same ICEpower 700AS2 engine. As a result, those products all exhibit identical performance and share the same sonic character. For example, Legacy Audio announced their Powerbloc2 “dual mono” power amplifier in early 2016 (it’s still in current production). It has a rated output capability of “325 Watts per channel x 2 @ 8 ohms, 650 Watts per channel x 2 @ 4 ohms”. Then, in late 2017, Parasound Products announced their ZoneMaster 2350 stereo power amplifier, with outputs rated at “350 watts x 2 @ 8 Ω” and “600 watts x 2 @ 4 Ω or 2 Ω”, as measured per “RMS, both channels driven, 20Hz to 20kHz”. The cited deviation between these amplifier’s power ratings is insignificant: 350 Watts is +0.3dB > 325 Watts, and 600 Watts is -0.3dB < 650 Watts. There’s simply no real difference. There are obvious variances in some peripheral features—stuff unrelated to power output—that might make one amp more or less optimal than the other for a given installation, but both amplifiers will deliver identical performance when driving the same speakers in the same listening room, and both will sound precisely the same when driven by an identical signal.** Given this congruence, it’s hard to explain the persistent (since 2017) list price gap of ~ $500 between these two closely related components, but I’ll do that now; see footnote.†

It’s reported, in some discussion forums, that both Wyred-4-Sound and PS Audio also utilize this same ICEpower 700AS2 amplifier module (or its single channel direct derivative). I’ve not tried to confirm this as fact because there are surely other OEM customers as well. ICEpower has apparently created a fine product, and the audio buffs that use it seem enthused and satisfied. Early feedback indicates reliable service life. Class D now looks literally as cool as promised, and it presents compelling possibilities—like a practical way to double your power output and consume half as much space—while spending no more than you’d normally allocate for half as much power and twice the size.

Be wary when shopping. Research class D high power amps with care, and question your judgement if your ears sense a brand-related advantage that can only be traced to random differences in exterior hardware. Amplifiers that use the same internal engine will always deliver the same sonic performance. Ears are not always so reliable as some think, and listening trials are never comparable when demonstrations involve different rooms and different programs. Focus on the published specifications, and on the detail that’s presented therein. Assure that the stated measurements are fully comparable, and that the results represent equivalent conditions. Beware when vital data is omitted. I feel that sloppy specs reflect a corporate focus that’s inconsistent with a healthy engineering culture.

This ongoing class D upheaval is big, but it’s not the only new audio trend afoot. Following are some of the other recent innovations that will eventually change the way we listen.

LOUDSPEAKERS: There’s a persistent trend away from big all-in-one-box loudspeaker systems and toward the use of smaller mains that are coupled with paired subwoofers.†† This evolution is the result of improved subwoofer design in combination with a new awareness of the ways in which we can tame the acoustic limitations implicit in typical home-size listening rooms. Multiple subwoofers can be utilized to effectively achieve partial cancellation of the reflected modal bass over large portions of the listening area†*. Two subwoofers will work well; more subs can be more effective—space permitting. The subs’ low bass output will naturally be ~ 180˚ out-of-phase with the back wall modal bass, so significant cancellation will result when those wavefronts converge. This can potentially improve near-field accuracy and generally enhance the perception of realism.

ACTIVE EXTERNAL CROSSOVERS: Better bass is isn’t the only benefit that paired subwoofers can bestow. After the paired subs are installed, it’s then possible to achieve a cleaner, clearer mid-range response by inserting an active crossover controller at a point in the signal path that's immediately before the power amplifier stage. This will allow you to dictate what feeds to the self-powered subs and what feeds to the main power amplifier + main speakers. It's always those big fat bottom bass notes that perpetually smear midrange clarity. When you divert the low bass and send it directly to the subwoofers (where it belongs), the main speaker’s mid-woofer drivers are then free to handle the upper bass and midrange frequencies independently, without disruptive low bass modulation. You'll get a clearer, more articulate midrange. The improvement is especially apparent when listening at high sound pressure levels. This midrange benefit is one of the most significant assets that a properly managed subwoofer setup can bestow, and many experienced listeners feel that it’s more important than enhanced bass.

BG (August 24, 2020)

*A well known and highly respected U.S. microelectronics company, Analog Devices, conducted intensive research and product development work on class D amplifiers over the course of the last two decades, and they published numerous technical papers for open peer review. Analog Devices also created and sold numerous class D products of their own design. However, their focus was the market for military and space research applications, and primarily involved high efficiency at modest power output, e.g. 5-10-20 Watts. Consumer electronics and power outputs ≥ 300 Watts at audio frequencies was never their objective.

**Legacy Audio’s Powerbloc2 and Parasound Products’ ZoneMaster 2350 stereo power amplifier exhibit near identical input sensitivities. The former specifies 2.19Vrms input for 325 Watts out across 8Ω (calculated voltage gain = +27.4dB), while the latter specifies 2.0Vrms input for 350 Watts out across 8Ω (calculated voltage gain ≈ +28.4dB). The related gain ∆ of just 1dB is simply inconsequential; it likely traces to calculated round-offs in combination with the manner in which the respective gains were originally derived, or measured, or expressed. In any case, it’s apparent that both Legacy Audio and Parasound Products are using the same active input, namely the amplifier’s basic “on board” input, as provided by ICEpower. There’s no evidence of any auxiliary active buffering.

†Legacy Audio, like Sanders Sound Systems, is primarily recognized as a producer of ultra hi-end loudspeaker systems. In both cases, these independent companies utilize transducers that tend to be lower in efficiency than what’s generally characteristic with conventional electro-magnetic drivers. (Legacy uses AMT type midrange drivers and Sanders builds planar electrostatic speakers.) As a result, both companies need on-site power amplifiers with very high output capability to properly demonstrate (and stay well clear of clipping) their proprietary loudspeakers to full advantage. The best way to assure this result is to utilize their own (house brand) high power amplifiers—amps that they know to be absolutely optimum for use with their speaker systems. The Sanders solution is a custom-designed proprietary amplifier with a high-bias class A/B final stage and multiple paralleled output devices in lieu of the usual (power-limiting) protection circuitry. Conversely, Legacy Audio’s Powerbloc2 is a high output class D amplifier that features the modern ICEpower 700AS2 engine. (As a consequence, the Powerbloc2 can be far smaller in size/weight than the Sanders amp, which requires conventional heatsinks.) It’s quite natural that customers who purchase a high quality speaker system from one of these sources would also want to buy the same power amplifier that was used when their speakers were demonstrated. That’s just good sales synergy, and a valid tactic that’s often linked to a nice discount on the complementary product. So maybe (?) Legacy’s Powerbloc2 amplifier is priced with that expectation; ask ’em.

††There are very few full-range floor-standing loudspeaker systems with woofers that are able to match the performance of a modern “mid-fi” self-powered subwoofer at frequencies from 20Hz to 50Hz. Nearly all of the very best floor-standers sag from 50Hz down, which is not surprising, given the fact that they’re also expected to reach 600Hz to 1kHz or more. Conversely, good subs are intended purely for 20Hz to 100Hz bass, a demanding but restricted niche that they’re specifically designed to serve, and where they consistently excel.

†*Refer pp. 234-262 of Floyd Toole’s “Sound Reproduction”, 3rd edition (2018), Routledge, ISBN 978-1-138-92136-8.