A Progress Report (Audio Tech Talk)

 by Bryan Geyer

Today, at a time when so many of us have experienced the audible benefit of properly implemented subwoofers, it seems archaic to assign a single driver as the sole bass source in a serious full-range loudspeaker. The spread from the bottom of the low bass passband (20Hz to 80Hz) to the top of the mid-bass passband (80Hz to 400Hz) is simply too wide for one transducer to handle, and the logical way to address that limitation is to split the 20Hz to 400Hz span, and apply separate power amplifiers to drive separate loudspeakers. Each of the assigned drivers can then be optimized as needed, with stiff, long-throw, piston-like air pumps for the ultra-low bass, and flatter, faster woofers for the middle bass. Implicit differences in efficiency would be of no concern because, with each leg driven by a captive amplifier, the respective levels can easily be balanced—or not—as desired. Overall bass levels could readily be adjusted to compensate for prevailing acoustics, as well as for the whim of the listener.

Giant single-driver bass design was initially popularized at the 1939-’40 New York World’s Fair, but we can do better today, and make everything look less cluttered. Compact class D power amplifiers, utilizing multi-layer boards and surface-mount components, can now be buried inside the loudspeaker enclosure. More efficient (also more precise, also less expensive) high impedance analog crossover* and equalization networks can be tailored to extract peak performance from a designated driver, and then blend smoothly with the ensuing upper bass and treble stage. Of course, these same desirable assets can also be implemented by digital means, and that cost-effective alternative is very popular today, despite the need to introduce yet another cycle of analog-to-digital and digital-to-analog conversion. This further complexity is avoided with the all-analog approach, so I personally favor pure analog simplicity, where less is more. But my personal bias is warped by the fact that I can’t test and verify what’s happening when the digital processing is implemented. Indeed, some of the digital simulation jargon seems artificially contrived**, but I’m an “old school” technician in every sense. I don’t own the kind of instruments (or the smarts) needed to appraise digital manipulation of an analog signal.

So who’s at the forefront of this improvement trend? Who is leading the charge to provide electronically augmented loudspeakers? Well, one niche that quickly embraced the integration concept is the mini-monitor makers. They commonly integrate customized power amplifiers with their speakers, but forego the lowest bass. That’s implicit with desktop expectations. The companies that produce hi-end full range loudspeaker systems can best mirror these improvements. Some already offer floorstanders with integrated subwoofers and multiple internal amplifiers. Some utilize digital signal processing (DSP); others might stick with classic analog design. Staffer Bill Heck has previously reported on his upscale speaker system from Legacy Audio; he uses it with his Wavelet 2 digital processor and says the sound is sensational. (So is the the price.) Editor Karl Nehring also favors hi-end Legacy Audio products. It’s obvious that this trend is active and evolving. More entrants should follow, maybe with models for modest budgets and smaller rooms. 

Stay tuned—check reliable reviewers, e.g., sites like Audio Science Review (https://www.audiosciencereview.com/forum/index.php) and Audioholics (https://www.audioholics.com/) — and stash away some savings; Nirvana may be near!

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*A Linkwitz–Riley filter ( https://en.wikipedia.org/wiki/Linkwitz–Riley_filter) that provides -24dB/octave attenuation is not particularly complex or costly, but tight precision is essential to ensure that the critical - 6dB down locus coincides precisely for both (low-pass and high-pass) of the filter sections, and that it is positioned at the desired crossover frequency. In practice, this is best achieved by “cherry-picking” the critical R/C components, so production gets messy when accuracy is vital. Digital control apps will tend to artificially obscure such production inaccuracies, but the output will reflect the full extent of any error.

**A DSP control application that I once monitored responded to my inputs by simulating graphic bar charts to mimic the impact of each command, just as if reporting a test result. Pure pseudo-science.

Addendum (by KN):

Bryan raises some important issues here that are well worth consideration. Indeed, it is a really tall order to ask a single driver to handle the frequency spectrum ranging all the way from deep bass up through the midrange – something’s gotta give. As he points out, one viable alternative approach is a good pair of two-way speakers augmented by one or better yet a pair of carefully matched subwoofers. There are many subwoofer manufacturers who offer models with not only built-in amplification and control settings, but also apps that allow tailoring of the system setting through your mobile phone or tablet.

 

Bill Heck and I have taken another route, opting for large multi-way loudspeaker systems that assign the lowest frequencies to what are in effect built-in subwoofer systems (a pair of 10” drivers crossed over at 180Hz in each channel of Bill’s system, a pair of 12” woofers crossed over at 120Hz in mine). To clarify, neither Bill’s Legacy Signature SEs nor my Focus SEs employ any internal digital amplification or crossover circuitry; they are both standard passive speakers with normal analog crossovers. Bill does employ the Wavelet 2 DAC /Preamp / Processor; however, that is a device entirely separate from the speaker. Moreover, it can be used with virtually any speaker, not just those from Legacy Audio. You can learn more about the Wavelet 2 in Bill’s review, which was in two parts: Part 1 is here and Part 2 is here.

 

Finally, I’d like to mention that there are several loudspeaker manufacturers that are employing advances in both digital amplification and signal processing to offer loudspeaker systems with amazing capabilities. One such example is the British manufacturer KEF, who offers several speaker models that are not only powered, but also incorporate Bluetooth, wi-fi, streaming services, etc. For example, the KEF LS60 Wireless (pictured) is triamped (100 watts Class AB for the tweeter, 100 watts Class D for the midrange, 500 watts for the woofers). It incorporates a 0.75” tweeter coincidentally mounted inside a 4” midrange driver, plus four 5.25” woofers (two on each side of the cabinet). The speakers can be connected together wirelessly or wired for higher-resolution connectivity. Each speaker has an RCA socket for connect an external powered subwoofer. There is an available KEF app that can be used for all manner of control and tailoring for frequency response, room settings, listener profiles. etc. You can also control the LS60s with Roon or Apple AirPlay – it’s a whole new world, folks. 

I’m still amazed that I can walk into my listening room, sit down in my listening chair, open my iPad, pull up Amazon Music or Qobuz, and control my NAD C658 streamer/preamp right from where I sit and listen to hi-res music through my stereo system with so little fuss. Or that I can prop my feet up in the recliner in my living room, turn on the TV, grab the Roku remote, and watch a performance by the Frankfurt Symphony Orchestra or Belle and Sebastian whenever I feel the urge. Yep, it’s a whole new world…

Downsize, Upsize (Part III)

by Karl Nehring

Those who have been following this series will recall that at the end of Part II (which you can find here) I mentioned doing some careful research into speakers as well as consulting with some knowledgeable audio experts, to whom I had some access by virtue of my position at The $ensible Sound magazine. (It was also through the magazine that I first became acquainted with John Puccio, who was the Classical Music Editor.) Based partially on some conversations with the late Tom Nousaine, I finally decided upon a pair of speakers from a small company in Springfield, Illinois, by the name of Legacy Audio. Actually, I had reviewed a pair of speakers from this same company a few years previously when they were doing business under the name Reel-to-Real Designs. Those speakers showed promise, but the company had made significant progress since then and their new flagship speaker, the Focus (pictured right), was just what I was looking for. Not only did they feature the extended bass response I was seeking from their multiple woofers, but their cabinetry was simply gorgeous. 

Next came my one diversion from the Focus model, as Legacy Audio’s designer, Bill Dudleston, was eager for me to audition a new loudspeaker he was coming out with called the Empire (pictured left). These were also large speakers, measuring 54"H x 13"W x 10"D and weighing 100 pounds, each but were of a more radical design than the Focus. The driver complement comprised three 12" carbon/cellulose woofers (two used primarily for bass frequencies, the third functioning as a "midwoofer"), two 5.25" midranges with cones made of Kevlite-Ti (a mixture of Kevlar, graphite, and titanium), and a 1" silk-dome tweeter. Except for the tweeter, all the drivers operated in dipole configuration. Although one might expect such a speaker to lack in bass, the Empires were solid down to about 40 Hz. For true full-range reproduction, however, the Empires required a subwoofer, so Legacy also sent along their Point One model, which featured a 15" floor-facing woofer and a 15" passive radiator at the rear of the cabinet. The internal Class D amplifier was rated at 750 watts. 

Although the Empire was in many ways an excellent-sounding unit, it never really took hold in the marketplace, and disappeared from the Legacy catalog after a relatively brief stay. My next pair of speakers was the next incarnation of the Focus model, the Focus 20/20 (right). This version sported three 12” woofers (two for bass, the third providing some phase cancellation to flatten the overall response), two 7” Kevlar midranges, and a 1.25” dome mid/tweeter plus a ribbon upper tweeter. The 20/20s served as my faithful reference for some years. The model gathered some excellent reviews and began to be used more and more as a studio monitor for mastering purposes. Still, designer Bill Dudleston knew that the speaker could be made even better as better drivers emerged in the marketplace. So, despite the success of the Focus 20/20, Dudleston rolled up his sleeves and went to work to see whether the new generation of drivers could lead to evolutionary improvements to the already solid Focus design package.

 

The first fruit of his labors was the Focus HD, a worthy successor to the 20/20. But Dudleston was not done. He envisioned a speaker that would take the design of the Focus HD and push it to new sonic and aesthetic heights. The end result of his quest was the Focus Special Edition (SE), a speaker that has changed in more ways than Dudleston imagined when he first contemplated implementing those evolutionary improvements to the Focus design. Taking the Focus HD as his starting point, he reshaped the cabinet, making it a bit narrower but deeper, plus stiffening and angling the sidewalls, front baffle, and top to avoid parallel surfaces. The Focus HD looked much like the previous generations of Focus speakers, albeit with different drivers. The SE (left), however, with its beveled surfaces and beautiful finishes, makes an indelibly striking first impression of quality. To my eye, at least, the design of the SE is reminiscent of Cadillac’s “Art and Science” design aesthetic, especially in its remarkable black pearl finish, which is the finish I ordered for my pair. 

As mentioned above, the drivers in the Focus SE were of a newer vintage and design than those used in the Focus 20/20. For the treble frequencies, the 20/20 employed a 1.25” upper midrange dome and a ribbon tweeter. The SE replaced these two units with two new neo-ribbon drivers. The very top end of the sonic spectrum was handled by a 1” Kapton pleated ribbon with a custom-machined acoustic chamber, a shaped lens to control dispersion, and a neodymium motor structure. The 3” mid-ribbon featured a push-pull neodymium magnetic structure with an ultra-low-mass vapor-deposited Kapton diaphragm. This driver operated below 8kHz to provide a transition to the cone midrange drivers. The two 7” midrange drivers were the same size as those in the 20/20, but are quite different in construction. The two 7” Kevlar midrange units in the 20/20 were superseded in the SE by 7 “ drivers in which threads of silver are woven into a carbon fiber diaphragm to distribute bending modes across the spectrum, then backed with a layer of ultra-light Rohacell. The two 12” bass drivers on the front panel were also different from those used in the 20/20. The aluminum cone woofers in the SE employ the patented AURA motor technology, which features a totally enclosed magnetic structure to provide excellent electrical damping. Two vents are mounted in the rear of the cabinet, but according to Dudleston, the SE does not use a traditional vented bass alignment; instead, the ports are utilized to lower the tuning frequency of the enclosure before electrical transformation is employed on the bass drivers. Exterior dimensions and weight of the Focus SE were virtually identical to the previous version at 55”H X 15.5”W X 13” D and 195 lbs. Sensitivity was rated at 94.5 dB. Overall frequency response is specified as -2 dB at 30 kHz and 18 Hz. Impedance is specified at 4 Ohms.

 

These speakers served me faithfully for more than a decade. I had listened to other fine speakers, but never heard any that ever caused me to think I might want to make a change. Oh, there were the Legacy Audio Whispers (right) – an incredibly open-sounding speaker that Bill Heck had reviewed for The $ensible Sound when it had first been released and which I had subsequently auditioned at Legacy’s Springfield facility. Bill and I both still have a soft spot for those speakers, with their amazing imaging capabilities, but neither of us has a room in which they would really fit; and besides, Legacy does not really offer them anymore. Fast-forward to the present, and Bill is quite content with his Legacy Signature speakers (see review here), which fit into his current listening room quite well. (As an aside, when I was completing my year of grad school at Kent State back in 1977 and had been accepted at Ohio State for the next year, the KSU department chair told me that when I got down to OSU I should look up fellow by the name of Bill Heck, who had been a grad student at Kent the year before me and then gone down to OSU. I looked Bill up, discovered that he was not only a great guy but also an avid audiophile, and we have been great friends ever since.)

Then, for whatever reason – although perhaps the realization that I had reached my seventies might have had something to do with it – I found myself thinking more and more seriously about the future. At some point, my thoughts went, my wife and I would no longer be able to go on living in rural isolation, meaning that we would most likely end up either moving in with or living nearby one of our children, or else moving into some kind of retirement facility. Hmm. In either event, we would be definitely be downsizing, meaning I would no longer have a room that could accommodate large speakers. I suddenly became consumed with the idea that I needed to prepare for this eventual downsizing of our living arrangements by downsizing my stereo system – which essentially meant getting rid of my big speakers and replacing them with small speakers. It was an idea that I just could not get out of my head no matter how hard I tried.

 

I have a good friend named Cortney who lives nearby and is an avid audiophile. I mentioned that I was thinking of selling my speakers, he expressed an interest, and soon we had settled on a deal. He went about selling some of his speakers and some other equipment that he owned and began paying me in installments. Meanwhile, I started trying to decide what speakers I was going to get to replace my SEs. I started doing some more research listening to some potential candidates, both by myself and with Bill Heck at some of the audio salons in the Columbus area. I auditioned various models from Bowers & Wilkins, KEF, Sonus Faber, GoldenEar, Revel, and Paradigm. Although I heard some especially good sound from the KEF and Revel models I gave a listen to, once again it was Legacy Audio that impressed me the most with their Calibre speaker, a three-way studio monitor  (4” AMT tweeter, 7.5” midrange, 8” long-throw woofer on the op of the cabinet augmented by two 8” side-mounted passive radiators). Unfortunately, the first time I had heard them, they were a partially disassembled “working” pair that Dudleston just kind of stuck the midrange driver back into right at the last minute and had them quickly set up so that I could hear them during the visit when Bill Heck and I were in Springfield so that Bill could audition the Wavelet. Although the Wavelet was certainly impressive, the Calibres sounded good, not great – but were obviously not a calibrated, finished pair. However, the time was soon coming when my friend was going to be paying me off completely. I needed to make a decision – and soon.

I have a son who lives an hour or so away from Springfield, so the next time Marilyn and I went to visit him, we arranged to visit Legacy and asked them to set up a good demo with the Focus and the Calibres. So this time the Calibres were a finished, tuned pair. Except for the deepest bass, they sounded virtually identical to the larger speakers. Marilyn liked them, so boom! My mind was made up. I was going to downsize! Not too long after I got back home, I ordered a pair of Calibres, plus I ordered a pair of SVS Micro 3000 subwoofers (on sale over a holiday weekend) to augment the bottom end. The Calibres were going to take a month or so to be delivered because of the production schedule at Legacy, which was fine, for I was in no huge hurry. This was going to work out great – even adding in the extra cost of the subwoofers, I was going to be ending up with some money left over. Marilyn was pleased by that idea…

 

Everything was falling into place regarding my grand downsizing project. For a time, I occupied my mind by thinking about where I was going to place the new speakers and subwoofers in the room, how I was going to match levels, what crossover frequency and slope I would wind up using, at what point I would possibly try to fine-tune things using the Dirac software in my NAD 658, etc. But as I thought more about such things, I began to realize that hey, I already had better bass response than I was probably going to end up with, I was not really going to be gaining any floor space, and that after enjoying and loving the big sound of Focus speakers for so long, it would break my heart to give them up – regardless of how excellent the Calibres might sound. Moreover, I realized it would be years before we would be leaving our home; truth be told, my downsizing idea had been an illusory obsession that had led me to make some less-than-optimal decisions. Now what?

 

What to do, what to do? The first – and most daunting – task was to admit to Marilyn that I now felt as though I had made a mistake and that rather than get the Calibres, I wanted instead to see about purchasing a new pair of Focus SEs, assuming it would still be possible. She was not thrilled, given that this meant that rather than making a little money on the whole deal I would now be spending several thousand more dollars – just to end up with essentially the same speakers that I already owned. Brilliant idea, dear husband! 

 

But she knew I would be miserable, and a pain to live with, so she gave her blessing. I immediately contacted Legacy and was able to cancel the Calibre order and order a pair of Focus SEs. I then contacted SVS, finding out to my great relief that I done so one day before their full refund/free return shipping window would have slammed shut. Phew – that was close! As it turned out, I had never even opened the boxes the Micro 3000s had been shipped in, so preparing them for return was a snap. A couple of weeks or so later a semi showed up to drop off a couple of BIG boxes strapped to a wooden pallet. Cortney came over with one of his friends and a sturdy dolly. Before long, my new SEs were standing where my old ones had stood, and what were now his SEs were on thir way to their new home in the back of his SUV. Even though it had started raining, we were both sporting big smiles!

So, what was the end result of my, ahem, downsizing effort? I went from a large pair of Legacy Audio Focus SEs to a pair of Legacy Focus SEs of yes, the same size, and spent a good sum of money in the process. My new pair is nearly a dozen years younger. The two tweeter drivers on the older version have been replaced by a 1” AMT super tweeter and 4” AMT tweeter. The older pair (which are now in Cortney’s system, where they sound really excellent – he loves them) the premium Black Pearl finish, while the new ones are in a standard (but still beautiful) finish, Black Oak (not the finith pictured at left. Sonically, what can I say? I loved the old ones; I love the new ones. However, one benefit of the whole “downsizing” fiasco was it spurred me into thinking more seriously about room placement. While I was in the process of fine-tuning the positioning of the new pair, experimenting with toe-in and such, I ran across a brief YouTube video that you can watch here a in which Gene DellaSala at Audioholics suggested experimenting with moving speakers closer together/listening position farther back to improve imaging. Intrigued, I gave it a try, and discovered that moving the SEs approximately eight inches closer together led to a more coherent stereo image on many orchestral recordings. Bingo! Several months and several thousand dollars since the beginning of my downsizing project, I had attained a definite sonic benefit. 

Not only that, I had downsized the space between my speakers by eight whole inches. After all. When it comes to downsizing successfully, it’s one step at a time, right? Hey, I’m on my way…

 

Downsize, Upsize (Part II)

by Karl Nehring

For those who might not have read Part I, which you can see here, at this point in the story I had just re-enlisted in the Army early in 1971 and used part of my cash bonus to purchase a pair of Bose 901 speakers. Because Bose recommended a minimum of 60 watts per channel for the 901s, I also sold my Kenwood receiver and purchased a more premium Pioneer unit rated at 65 wpc. (Some old-timers might remember the McIntosh clinics, in which McIntosh dealers would have a representative from the McIntosh factory come to their store and set up a test bench. The dealers would invite customers to stop by and bring their amps and receivers in to get measured to see whether they met their published specs and how they stacked up against McIntosh and other gear the dealer might be peddling. I was quite happy to find out that when I brought the unit in for testing at one of those clinics more than seven years after I had purchased it that the McIntosh rep, a really professional gentleman in a white shirt and tie, found that the old Pioneer met or surpassed all its specs. In fact, he commented that it was a first-class receiver, a cut above most of the units he had tested of its vintage.) Some audio buffs turn their noses up at the idea of the Bose 901, but at the time, it truly was a remarkable product, especially in relation to what else was out there. I had come close to purchasing KLH 5s, but preferred the 901s overall.

 

A few more quick comments about the 901s before I move on. First, in terms of music listening, the early 1970s were – at least for young white American males like me – the era of rock and fusion. The record collection my wife and I had assembled comprised mainly our 60s rock records, some folk (Joan Baez, Joni Mitchell, etc.), a few orchestral LPs, and a rapidly growing number of jazz-rock fusion releases (e.g., Return to Forever, The Inner Mounting Flame, Bitches Brew), and this stuff sounded really good through the 901s. Another thing to recall is that after the original 901s, Bose decided they needed to be more efficient, and went from a sealed to a ported design, giving up some bass to gain some efficiency. No, I am not saying the Bose 901s were the be-all and end-all; however, they were certainly not as bad as some folks have claimed. Anyway, back to the story…

We returned to the USA in January of 1974, bringing the stereo system with us and continuing to acquire new LPs to enjoy through the 901s, including Weather Report’s Mysterious Traveler, Antonio Carlos Jobim’s Stone Flower, and Joni Mitchell’s Court and Spark. In February of 1975 I was honorably discharged from the Army. Because BYU had a policy that granted those on academic suspension the opportunity to re-enroll upon their successful completion of military service, Marilyn and I moved our two young sons, our records, and our stereo into a small basement apartment in Provo, UT, in April. That very first semester, I signed up for an elective course in music appreciation that would change my life, for the professor, Dr. Earl, made classical music come to life in a way that immediately captured my attention and imagination. The next thing you know, I was buying all manner of budget-label classical LPs. My time in the Army plus my becoming a family man had made me much more mature, meaning that now I was able to do well in my classes. Not only that, I had a beautiful wife, two healthy kids, a rapidly growing record collection, and the world’s best speakers. What more could I possibly want? 

 

As you might guess, I soon found out…

 

One fateful day I strolled into a stereo store to purchase a replacement stylus for my cartridge. The salesperson asked about the rest of my system, and when I mentioned rather smugly that I owned Bose 901s, he said something along the lines of, “well, those were certainly exciting when they first came out, but they’ve been surpassed these days. And if you like them because of that reflected sound, I can show you something right now that does a better job.” I then spent some time listening to some Sonab speakers from Sweden that did indeed do a better job. Needless to say, when I got home and told Marilyn that I had heard speakers I liked better than our 901s, she was not too thrilled. You see, when I had bought the 901s, the line I used on Marilyn was that we would never again need new speakers. Hmmm. 

 

Although I did not wind up with the Sonabs, hearing them started me on my speaker quest. I spent a lot of time hanging out at various audio stores, records in hand, listening to various speakers. I was quite taken by the Dahlquist DQ-10s, but could not afford them. Then I discovered a brand-new speaker that I liked even better than the Dahlquists, the DCM Time Windows, but no, I could not quite afford those yet, either. So at this point I finally wound up purchasing a pair of Polk Audio Monitor 10s (right), which sounded quite good for their asking price. And they were big speakers. Maybe not huge, but certainly big. They had a full sound, with some heft and impact, but also a reasonable amount of detail and transparency for speakers in their price range.

So it was the Polks through the rest of our in time in Utah, where in the spring of 1977 I completed my undergraduate studies. It was a great feeling to leave this time not as I had been forced to leave eight years previously – academically suspended – but as the recipient of two bachelor’s degrees (communications and philosophy). We then headed back to Ohio for a year of grad school at Kent State; by the end of that school year, I had been invited to join the staff of The $ensible Sound, an independent audio magazine that focused on more affordable equipment, and I sold the Polks with the idea that when we got settled in our next residence (I had been accepted for grad school at Ohio State), I finally would get the Time Windows that I had been wanting and saving for.

 

In the summer of 1978 we moved into the house where we still live today, in a rural area northwest of Columbus, Ohio. Here I finally had the luxury of a relatively large room that could serve as a dedicated audio room. In addition, our nearest neighbors lived a quarter-mile up the road, so I could play loud music any time, night or day – unless it would disturb Marilyn or the kids. I quickly set up my new pair of Time Windows (left) which produced some remarkably good sound in our new home. I had picked up an Onkyo A7 integrated amplifier to replace the old Pioneer receiver, and then came a used Son of Ampzilla (I retained the Onkyo for a time for its preamp section). But hey, I digress once again. Back to speakers!

 

After the Time Windows came KEF 105s (right), which offered better bass heft and impact than the Time Windows could offer. By now I was doing more and more with The $ensible Sound, at some point becoming Associate Editor, and then later, Editor. I had all kinds of equipment showing up for review, including speakers. I’m not exactly sure just what speakers I actually owned and which I had on extended review from among the following, although most I believe I owned, and most of which were relatively large speakers with plenty of bass wallop. At any rate, after the KEF 105s came a pair of Vandersteen 2Cs, which seemed to have better transparency and imaging than the KEFs. Somewhere along the way was a pair of B&W 802s, beautifully made but just too warm-sounding. The next two pairs were both from JSE, featuring the patented “Infinite Slope” (~100 dB/oct) crossovers designed by Richard Modaferri (legendary McIntosh tuner designer and one of the nicest people in the business), the medium-sized Model 1s and then the full-sized Model 2s.

 

Then came the Carver Silver Edition Amazing Loudspeakers (left) – this pair was a long-term loaner, which at some point received upgraded ribbon drivers that were installed by Bob Carver himself. Alas, although these speakers did indeed sound amazing most of the time, the ribbons tended to buzz occasionally when hit with plucked guitar notes at energetic listening levels. So I decided it was time to go back to a speaker with dynamic drivers, so I started doing some research and making some inquiries around the industry. Finally, after extended consideration and consultation, I made up my mind and ordered a pair of large, full-range speakers with extended bass response. It would prove to be a fruitful and fateful decision.

 (to be continued)

 

Downsize, Upsize (Part I)

by Karl Nehring

 

We have lived in our rural home for 45 years. Within a year or so of settling in, I purchased a pair of KEF 105 loudspeakers. Although over the preceding years I had owned several pairs of speakers with good performance, the bass capability and overall sense of ease that the KEFs brought to my listening room increased my enjoyment of music and convinced me that large speakers were the way to go given my fondness for large-scale orchestral works by Mahler, Shostakovich, Vaughan Williams, et al. Since then, I have owned or had in house for an extended length of time (I was the editor of an audio magazine for nearly three decades) several pairs of relatively large loudspeakers. However, about a year and a half ago I decided that after all those years of large speakers, it might finally be time to downsize from the pair I owned at that time, my beloved Legacy Audio Focus SEs (pictured) – and therein lies a tale…

 

First, however, a bit of background. The first stereo my family ever acquired was one of those little systems sold by salesmen who would come into your home and give a sales pitch for stereophonic sound by playing some demonstration tracks, the highlight of which was the ping-pong track, where we could hear the ball flying back and forth across our living room. Amazing! The record player was made –or at least branded – by a watch company (Longine’s or Bulova as I recall), and came with boxed sets of records from Reader’s Digest. My parents purchased several of these boxes, which were organized by musical category. I can’t remember them all, but there was an orchestral set that served as my introduction to classical music; I can still vividly recall being swept away by Debussy’s La Mer and being amazed that someone could compose something so breathtaking.

 

Our new stereo system came right around the time of the British Invasion, so of course even though we now had several boxes of records to listen to, we begged for some rock & roll records to play on our new stereo. A few days later, my mother came home from work with Beatles ‘65 and Mr. Tambourine Man by the Byrds. I played them over and over again, soon knowing every lyric by heart. By hearing them in stereo, I was struck by how goofy the stereo mix for the Beatles was – voices in one channel, guitars in the other. What the heck?! I soon made my first record purchase, Bringing It All Back Home by Bob Dylan. I thought it was the most profound thing I had ever heard; however, it drove my father up the wall, and before long, I was forbidden to play any Bob Dylan records when he was home. This system was also the one on which I played my first classical purchase, the Reiner/Chicago recording of Tchaikovsky’s Symphony No. 6. My high school band, in which I played bass clarinet,  was preparing a wind arrangement of the march movement for the Indiana state band contest, and I had become fascinated by the music and wanted to hear the whole symphony in its original form. Our band got the highest score in the state and the Pathetique is still one of my favorite symphonies.

 

Within a couple of years our family life was drastically changed when my father died suddenly from a heart attack. We wound up moving from our house on a one-acre lot to an apartment. I don’t recall what happened to our first stereo, but now we had one of those all-in-one TV/stereo consoles (a Motorola, I’m pretty sure). I was buying plenty records, mostly rock, although I also purchased my first jazz recording, New View by saxophonist John Handy, which also featured Bobby Hutcherson on vibes. A technological highlight of the console stereo was the reverb dial, which allowed you to add artificial reverberation to whatever you were playing. Adding just a touch to some of those rather dry rock recordings could make them sound a little more pleasant, but for whatever reason I would occasionally find myself getting into a mood that would result in my putting on Bob Dylan’s song “Visions of Johanna” and cranking the reverb dial way up. It was frightening.

 

Then it was off to college the first time with, alas, no stereo of my own in my dorm room, although I had taken some favorite LPs with me and occasionally got to listen to them on the console setup in the commons room. A really poor semester cost me my Honors Program scholarship and left me on academic probation (in hindsight, I now realize I was deeply depressed), I headed back home, where my mother and sisters had moved from the apartment into a house in another town. Then my mother got sick, couldn’t work, I worked full time and took care of her and my four younger sisters, and we moved into another house, where she became completely bedridden. On the good old Motorola console late some evenings evening I played the Blood Sweat and Tears album with David Clayton-Thomas, which my mother thought was wonderful until I showed her the cover and she was crestfallen to see they were “just a bunch of hippies.” Still, that console provided plenty of musical enjoyment for us both, along with mental and emotional sustenance that we both needed. 

But her condition continued to worsen. She was transported to a hospital in Chicago, then finally to a rest home in Rogers Park, near her father. Driving home from seeing her after what had been a deeply emotional visit, I listened to the Apollo 11 coverage on the car radio. On July 20, 1969, Neil Armstrong set foot on the moon. On July 21, my mother passed away. By the end of August, my sisters had been taken care of and I had purchased a little Allied Radio stereo system to load into the trunk of the Chevy Impala I inherited from my mother so that I could have music in my dorm room this time around.

 

Unfortunately, I still could not get my academic act together. I got high grades in a couple of classes, but failed to complete the rest. I went from academic probation to academic suspension. The one bright spot of that whole experience was meeting a young woman named Marilyn, with whom I immediately hit it off. We began dating, discovering that we had a lot in common – especially our love for and tastes in music, and in the summer of 1970 I would drive from Indiana to Ohio to visit her. We were seriously in love, but there was one little problem: the Selective Service folks now realized that I was no longer eligible for the hardship deferment I had received for taking care of my sisters while my mother was ill, and my miserable academic record meant that a student deferment was out of the question. I had been included in the first draft lottery and drawn the draft number 111. In July, 1970, I visited my draft board to verify that the official change of my draft status to 1A was in the works and would probably occur within a couple of weeks – and they were drafting numbers around 150 or so. I asked the woman ay the draft board whether there was a recruiting office in town; she replied that there was one upstairs above the drugstore right across the street. 

I crossed the street, climbed the stairs, and asked the Army recruiter whether he had anything that would keep me from going to Vietnam. He asked me whether I could score well on tests – I may have been suspended from college, but test-taking was always a breeze for me. I scored high on the tests, which made me eligible to sign up for Pershing missiles, which meant I could only be stationed in Germany or Oklahoma. I joined the Army in August (Marilyn and I had a serious discussion and agreed we would get married when I completed my service in three years), called Marilyn from a phone booth at Ft. Lewis after about my third day of basic training to say we should get married sooner because I had found out it was feasible to live as a married Army couple in Germany), got engaged over Christmas, then I said goodbye and headed to Germany in January, 1971.

 

By now, my guess is that many – perhaps most – readers are wondering what any of this has to do with speakers. Quite a bit, actually. Because Marilyn and I were both devoted music lovers, I knew our future apartment would have to have a decent stereo system. So a couple of months before returning to the states to get married, I went with my best buddy and his wife down to the Audio Club at Patch Barracks in Stuttgart, where audio equipment was available at a discount to military personnel. There I bought my first component system, which comprised a Philips turntable with an Elac cartridge, a Kenwood receiver rated at 23 watts per channel, and a pair of Wharfedale bookshelf speakers. I can’t recall the model, but they were two-way sealed design with a woofer in the 6-8” range. We set up the system in my friends’ apartment (mine was not yet ready) so they could enjoy it until I came back with Marilyn. We put on American Beautyby the Grateful Dead and were floored by how good it sounded. The Wharfedales were surprisingly nice little speakers.

 

But life was changing fast. I was getting promotions, I was getting married and moving out of the barracks into an apartment, and I had discovered Mahler and Beethoven. Not only that, I had made some return visits to the Audio Club, started reading stereo magazines, and had caught the audiophile bug. As nice as the Wharfedales were, they would not remain in my system for long. Early in 1972, I re-enlisted for three more years in the Army and then used part of my re-enlistment bonus to purchase the speakers of my dreams, the original Bose 901s. Thus began more than 50 years of speaker madness.

 

(To be continued)

The Legacy Wavelet II (Part 2)

by Bill Heck

In part 1, I introduced you to a radically different product, indeed a different product category: the Legacy Wavelet II, a music DSP processor. If you've not read that article, check it out here. In part 2, I discuss the results of deploying the Wavelet II in my system and suggest how it might work in yours.

Results

DAC and Preamp: Yes, these functions work well and sound excellent, as expected. There may be subtle differences relative to other products of this sort, but again we’re looking for big changes, not subtle ones. For us today, it’s go big or go home.

Crossovers: As my Legacy Signatures are bi-amp capable and I had an extra older but excellent amp lying around, I figured why not go for it? To make a longish story short, things never sounded quite right with the two different amps, so I eventually sprang for a second PowerBloc2, and all was well. I still don’t know just why the original amp did not work out, and Legacy assures me that other customers have successfully integrated two (or more) different amps. YMMV.

So, is bi-amping worthwhile? On one hand, the effects, while real, are not the sort that revolutionized my listening experience. In other words, we’re back to subtle – although certainly real – improvements, and then there’s the expense of a second amp. On the other hand, amps are getting less and less expensive, and bi-amping is another way to wring a last, noticeable bit of performance from bi-amp-capable speakers. That performance included slightly deeper bass, as confirmed by using test tones, and a subjective sense that the midrange was “cleaned up” a bit. For those already into multi-tens of thousands of dollars territory, it certainly makes sense; if you’re in for that kind of money, you can afford an extra amp or two. In my case, I don’t foresee upgrading the speakers, so my final available avenue for optimum performance was indeed bi-amping.

Oh, about those two channels reserved for subwoofers: I do have a subwoofer and in theory I could use it to fill in extremely low bass (mid-20’s Hz and down); I’ll give it a try when I have some extra free time.

Room Correction / DSP: Here’s where things get really interesting. With apologies to Captain Kirk, DSP is the final frontier, at least for stereo listening. I said that I didn’t want “subtle”; the effects of room correction and other DSP processing are anything but.

I’ve had considerable experience with at least one well-regarded room correction system: Dirac Live (full range version), which was built into my previous preamp. Although I felt that Dirac involved a few compromises, I found that overall, it almost always made noticeable improvements in the reproduction of live music, particularly in the areas of imaging and the reduction of resonances in the nether regions of the spectrum. (I should add here that there are room correction approaches that require multiple additional speakers or subwoofers. I have enough difficulty with the economics and aesthetics of a stereo pair, so for me such systems are not real world options.)

Because I had both the Wavelet II and my older preamp during the transition from my old speakers, Waveform Mach Solos, to my new Signatures, I was able to compare the effects of the Dirac and Böhmer systems within fairly short time periods with both sets of speakers: not true blind testing by any means, but enough (I hope) to develop fairly reliable impressions. To my ears, the Wavelet II’s Böhmer room correction was smoother and more effective, with fewer compromises, than Dirac’s. For example, Dirac tightened bass but at the expense of lowering the perceived bass level; an acceptable tradeoff for me, but Böhmer manages the tightening part without the perceived reduction part. Moreover, Dirac correction works for a specific location; as you (or just your head) start to leave that location, the correction breaks down. To be clear, while you do not need to keep your head locked as though in a vise, moving even a short distance across the sofa is problematic, and moving several feet away is somewhere between disappointing and disastrous. In contrast, the Böhmer correction is constant throughout the room; indeed, I’ve found that I can get a reasonable stereo image while lying on the floor in front of the speakers. (Not that I recommend that listening position in general, but after a long day with an aching back….). Finally, to my ears, the Böhmer correction just sounds more “right”, more “natural”.

Microphone in front of
speaker for room correction.

Meanwhile, the Böhmer correction is far easier to set up. Typically, room correction systems require multiple closely spaced microphone measurements in a listening “window”; the Böhmer approach uses just one measurement per side with the microphone at about tweeter height 48” in front of the speaker. After my first time running the Dirac process, I could replicate it in something between 45 – 60 minutes; replicating with true precision was difficult and demands something like a boom microphone stand to do properly. I can run the Böhmer in under 10 minutes, including positioning the microphone with truly anal attention. Complicating any measurement regimen is the fact that you should conduct any measurement regimen with as little environmental noise as possible; the shorter the process, the less likelihood of interruptions from plane flyovers, trucks passing by, and furnace or AC systems kicking in. The bottom line: it’s easy to set up the Böhmer correction initially, and also to rerun it you change anything in or near the system.

Now let’s zero in on details of what the Wavelet II does for music. Fortunately, it was easy to switch the Wavelet II’s room correction on and off instantaneously to evaluate its effects. (The switch did insert a fraction of a second of silence, so it wasn’t literally instantaneous.) Here’s are some results:

Orff: “0 fortuna” from Carmina Burana, Seji Ozawa / Boston SO: The most obvious effect of room correction was that the words sung by the chorus were more intelligible. (Sadly, room correction did not translate those words into English. No doubt the Universal Translator Upgrade will take care of that.) The orchestral backing and male voices also had slightly more weight.

Quarter Chicken Dark Yo-yo Ma:Room correction brings up the mid to lower bass without changing the overall volume.

Given that I ran these tests around the Christmas holiday, it seemed appropriate to try some passages from Tchaikovsky’s Nutcracker ballet.

Act 1, No. 7: The Nutcracker Battles the Army of the Mouse King, Gergiev / Mariinsky Orchestra: The crack (gunshot?) just after the movement begins seems a little louder with room correction off. But, with room correction on, the initial pop, meaning the leading edge of that shot, is more startling, distinct, realistic, and exciting. (Seriously. I jumped.) Similarly, at the very end of the movement, the repeated plucked double notes on the basses are deeper and more resonant. In general, turning on room correction clarifies the various instruments; it also brings the orchestra forward slightly.

Piano transcription by Stuart Goodyear, TH14, act 1, tableau 1: With room correction on, the lower registers of the piano have more body, as does the big chord at the very end.

Waltz of the Flowers, Los Angeles Guitar Quartet: The contribution of room correction was particularly noticeable with this recording. The guitars not only have more body, but it also is easier to tell that there really are several different instruments playing different parts. With room correction off, you still hear all the notes, but it’s not so clear where each line is coming from. Metaphorically, with room correction off, we have a caricature of some guitars; with room correction on, four people are playing individual guitars.

Nutcracker Suite as arranged by Duke Ellington and Billy Strayhorn; played by the Harmony Ensemble of New York, conducted by Steve Richmond. I promised classical music, and I suppose this just sneaks in under the wire, but this wonderful arrangement sounds more delightful with room correction on. Without correction, the sound is noticeably two-dimensional on a plane in front of the speakers. Turning on room correction opens it up, adds a little punch, and just helps things fly along.

The second form of DSP offered with the Wavelet II is the aforementioned “Omnio”. Subjectively, the effect is obvious, and here’s my best effort at description: Imaging is “solidified”, made more three-dimensional and precise, with instrumental and vocal positions clarified. The image also is deepened front to back, while the overall sound fills out, with instruments and voices having more tonal depth or body. For example, in orchestral music the brasses and woodwinds are more clearly behind the strings, and the sound of the orchestra is “thicker” (in a good sense), as though more of the full sound of each instrument comes through. An abbreviated way to say all this is that the sonic “picture” of performers in space became significantly more believable, which is not the sort of thing that one normally hears by simply flipping a switch.

These benefits can be recording dependent. Omnio really rescued some recordings: for example, without Omnio, the Supraphon recording of the Dvorak Symphony 6 with Mackerras leading the Czech PO had the violins plastered to the left speaker. With Omnio, the sound was not perfect, but the violins managed to move back toward the rest of the orchestra. In contrast, in the Vox recording of Rachmaninoff’s Symphony 2 with Slatkin / St Louis, now remastered and reviewed on Classical Candor here, things sound more confused and messy with Omnio on. (Apparently, this is because the recording originally was mastered for 4-channel – shades of Quadraphonic! Omnio is stumped when trying to figure out what to do.) Fortunately, a simple tap on the control app turns Omnio on and off, so it takes only a few seconds to decide whether to use it or not. When you do turn it on, note that the perceived volume increases, so adjust accordingly. In any case, over the months I found myself happily using the Omnio feature for most recordings.

But wait, what about that Omnio+ thing that I mentioned earlier? With the current firmware, you now can choose Omnio Bypass (meaning off), original Omnio, or Omnio+. As I hear it, Omnio+ is indeed "plus": Omnio, only moreso. In particular, with the original Omnio I occasionally felt that the central image might be a little “clogged up”; Omnio+ eliminates that issue while providing even clearer imaging with a more natural feel. Omnio+ also seems to work a little more reliably, although not always perfectly, with problem recordings.

One editorial comment: product descriptions and other reviews that I have seen of both the original Wavelet and the Wavelet II generally give but little attention to the Omnio feature. I find this surprising. I said earlier that Omnio/Omnio+ make an immediately noticeable change, i.e., one that is not subtle. This is just the sort of improvement that you can obtain only with advanced DSP, and as such, it is a big deal. It’s why one would be interested in a unit such as the Wavelet II – and it may be a harbinger of even bigger changes to come.

Minor Gripes

Lest I be accused of seeing only the bright side, I will admit to a few minor gripes.

On the hardware side, the USB connectors on the rear panel all are USB 2; I wish they were USB 3.1 to help future-proof such a premium device. The USB digital audio input connector could be a micro-B, an A, or better yet the new universal C standard connector rather than the old-style original B-connector. WiFi connection is by means of an adapter plugged into one of the USB communications ports; that’s fine, but the adapter is restricted to WiFi 802/n, using only the older 2.4 GHz band. Finally, although WiFi setup is done only once (unless something changes in your network), the process is a little cumbersome.

In Böhmer/Legacy’s defense, one can argue that they should allocate development resources to hardware and software improvements, which is exactly what they have done – but a few minor tweaks still would be nice. Anyway, that’s the end of my nit-pickng.

In Summary: The Wavelet II

The Wavelet II is an extraordinary product with powerful sonic capabilities. I’ve barely touched on the technology involved, preferring to concentrate on the more accessible features and sonic outcomes. But there’s no doubt that we are operating here at a frontier of sound reproduction.

In my earlier overview of the Legacy Signature speakers, I stressed how “real world” they were; in a different way, the Wavelet II also is a real world product. A simple, intuitive user interface combines serious processing power and control flexibility to work with real systems in real rooms. Sure, it’s nice that the Wavelet II is suitable for use with superspeakers in purpose-built audio rooms that already are full of treatments and tuned to perfection, but it’s really exciting that it works even for lesser speakers in plain old real rooms in real houses, condos, or apartments. (One hesitates to think of the prodigious capabilities of big Legacy speaker unleashed in apartments with unsuspecting neighbors...but I digress.) Obviously, the room correction is front and center, but don’t forget the Omnio / Omnio+ processing. And, of course, there’s the bi-amping capability if your speakers support it.

But what about the price ($7950)? By the rarified – feel free to pick a less flattering adjective – standards of “high end” audio, with folks shelling out well into five figures for everything from phono cartridges to cables, the Wavelet II is not particularly expensive. However, by more down-to-earth standards, it’s a significant investment.

Meanwhile, though, a lot of audiophiles spend a lot more on equipment and accessories that return a lot less than the Wavelet II provides. Also, the price is easier to swallow when you remember that the Wavelet II obviates the need for a separate preamp and DAC. In my own system, given that it would be difficult for several reasons to upgrade my speakers, the Wavelet II is by far the single most significant upgrade that I could have made. In fact, I would speculate that, in many (most?) systems, investing in a Wavelet II could make a bigger difference than an equivalent investment in new speakers. Here’s the point: at the least, you really should try to hear a Wavelet II in a system fully set up to use it. DSP truly is the final frontier of audio; the effects are immediate and obvious.

The Crystal Ball

I suppose that I shouldn’t even mention this last bit, as Legacy has plenty on their plate already, but here’s a dream: could there be a less expensive “mini-Wavelet”? Dump the analog inputs and maybe even a digital input or two, make the output just four channels (for bi-amping) or even two channels (single amp), maybe back down the numeric processor to original Wavelet standards (it used a lower bit depth and a shorter processing window), all to bring the price down to a level that might be accessible for those earlier on the curve of building their audio systems. Böhmer room correction, Omnio processing…it’s a dream of bringing this kind of power to a wider audience. I hasten to add that this is my dream; I certainly can’t speak for Legacy or Böhmer. But wouldn’t it be nice?

Meanwhile, take a listen and imagine what the Wavelet II might do in your listening room. If you are tired of swapping similar components to eke out tiny gains, maybe it’s time, as Monty Python would say, for something completely different.

The Legacy Wavelet II (Part 1)

by Bill Heck

As music lovers with nice stereo systems, many of us are subject to periodic fits of “upgradeitis” – the desire to change something, anything, to tweak our systems for that next level of sonic improvement. But looking at the many upgrade options in the audio world, especially the front end electronics, I think that we’re aiming too low.

The prices that we might pay certainly aren’t too low: anything but that, when the cost of fancy versions of the most basic products soar into tens of thousands of dollars. No, I’m dissatisfied because the rewards that these products aim for, and maybe even sometimes deliver, are so small. You don’t need to believe that amps, preamps, or DACs, much less cables and such, “all sound the same” to suspect that the differences among them are mostly subtle, regardless of the sometimes rapturous reports of certain reviewers. (Speakers are a different story; I’m talking about everything up to that point.)

Hey, I appreciate subtle improvements as much as the next music lover. But if I’m spending big bucks upgrading audio components, I don’t want subtle. I don’t want something that I can identify 80% of the time in a blind test; I want something that no one could possibly miss even once. If we spend serious money, shouldn't we get serious returns? Not on the edges, not tiny changes, but major upgrades, differences obvious to the most casual listener. We try to get excited about little gains, but maybe that's because it's been so long since we've had any big gains.

Let’s take a moment to think about why the effects of changing front end components might be subtle. The issue is that these components are mostly pretty doggone good already: electronics with vanishingly low levels of various distortions and digital signal sources that already provide fidelity beyond the limits of human hearing. Moreover, despite audio folklore, human hearing is not particularly sensitive to the kinds of differences (distortions, if you like) that remain at this stage of the audio reproduction chain.

So, if making the musical signal even cleaner is not where advances lie, how do we improve matters? How about changing the signal, not accidentally but with purpose, changing it so that the sound that arrives at your ears better reflects that sound that the performing musicians made originally? In other words, we can modify the signal to correct for, or adapt to, the listening room and to recover or enhance information otherwise lost in the recording process. Yes, that’s Digital Signal Processing (DSP).

Legacy Wavelet II

Enter the Wavelet II. (The original Wavelet has been replaced by the Wavelet II, which is the one that I have and am discussing.) This product, the result of a partnership between Legacy and Böhmer Audio, is a rare beast in the consumer stereo market, one properly characterized as a dedicated DSP product. Sure, there are DSP capabilities built into other products, such as AV receivers, mostly to provide room correction (with varying degrees of success) and to synthesize spatial effects in multi-channel systems. In the two channel world, the aim usually is room correction only, often as an “add on”’ for preamps and such. In contrast, the Wavelet II is primarily a DSP processor offering a unique approach to advanced room correction, plus features aimed at what we might call “music restoration”. The Wavelet II is one of a very few components that does not just sneak across the DSP frontier but bounds fearlessly past it.

To clarify, the Wavelet II does provide the functionality of a preamp and a DAC, not to mention a multi-way crossover. But these features come along for the ride, so to speak: the functions provided by the Wavelet II are built on an advanced processing platform to provide a complete front end, allowing optimization of the entire package while making things convenient for the user. (You can get an idea of how it hangs together from this block diagram at the Böhmer website.)

In what follows, I’ll focus on the unique features of Wavelet II. This means that, in the interest of keeping the length of this article under control, I’ll give short shrift to some aspects; please excuse those omissions.

Description

As with my earlier review of the Legacy Signatures, I won't go into the specifications that you can easily read here on the Legacy website, but a quick summary and orientation may be useful.

Wavelet II Rear Panel

The Wavelet II is both figuratively and literally a black box. I’ve not tried to open mine; you can get an idea of the contents by reading the description on the website. The details are proprietary, and of course with a unit like this, the real action is in the software.

Externally, the digital and analog inputs are more or less typical for a preamp. The output side is more interesting: each of the eight (not a typo) output channels sports balanced and unbalanced connections. Why eight output channels? The short answer is crossovers: I’ll describe their use below.

Wavelet Controls on Android Phone

As to the controls, there are physical buttons and a dial for basic functions on the front of the unit; I hardly ever use them. In addition, a small remote control for basic functions is included with the unit; I’ve never taken it out of the box. The obvious way to control the Wavelet II is with the browser-based app. My own daily driver is a repurposed old Android phone; my Microsoft Surface Pro works well, too, and the Legacy folks swear by iPads.

It was the work of a few minutes to figure out the control app. I particularly liked the clever “fine” volume control, which makes the kind of adjustments that you are likely to make a matter of a few taps. Another nice touch is that the apodizing filter, room correction, and Omnio functions (described below) are turned on or off with simple checkboxes, all of which are located on the main dashboard page – very handy for quickly assessing the results of each function.

Functions

Let’s walk through the major functions of the Wavelet II.

Digital-Analog Converter (DAC): Yes, the Wavelet II includes a DAC. (Do any digital products these days not include a DAC?) Of course, you could connect your source to your favorite DAC and connect that to one of the Wavelet’s analog inputs. But given that the Wavelet II digitizes analog inputs to do its DSP thing, why bother? By the way, you can switch on the fly between linear and apodizing filters (the latter to reduce pre-ringing) but that’s one of those subtle effect items that I’ll not spend time on here.

Preamp: The Wavelet II functions as a preamp. Not to insult the Legacy folks, but there are oodles of preamps on the market, a lot of them are very good, and in real world conditions, the differences among them are, well, subtle. (The Wavelet II does provide a neat set of “Contour” sliders that are unusual and particularly handy. You can read about them in the Wavelet II manual.) Subtle is not what I want to write about today, so again I’ll move on to what makes the Wavelet II unique.

Crossover: Although electronic crossovers are hardly new, finding one integrated into a single component with all this other functionality (preamp, DAC, DSP) is unusual, so I’ll spend a little time on it. Of course, a crossover is relevant only if you have something to cross over, either speakers that allow bi- or multi-amping, or perhaps regular speakers plus subwoofers.

For those readers unfamiliar with the concept of bi- or multi-amping, here’s a brief introduction. (You other folks can skip ahead.)

You probably know that your speakers contain crossovers that divide up the frequencies of music and send them to the appropriate drivers, e.g., bass frequencies to the woofers and high frequencies to the tweeters. In “bi-amping”, the idea is to insert an active (electronic) low-level crossover before the amplifier instead of relying on a passive one contained in the speakers. The active crossover thus directs bass frequencies to one amplifier and higher frequencies to a second amp. At the speaker, the bass amp connects to inputs (binding posts) that feed only the low frequency section of the speaker; the high amp connects to what remains of the speaker crossover to drive the midrange and up. To make this work, you need three things: (1) bi-amp capable speakers, i.e., having separate inputs for bass versus higher frequencies; (2) an active crossover in or after the preamp; and (3) a second amp.

Why mess with the complications of bi-amping? There are several theoretical reasons, including providing more total power to the system; moving the stress of higher power handling to just the bass amplifier; improving crossover accuracy and consistency; keeping large back EMF out of the amplifier handling the higher frequencies; and isolating distortion to low frequencies. (Details about the benefits of bi-amping can be found on the Web.)

So with the Wavelet II, the crossover characteristics specific to your speakers are programmed in before the unit it is shipped to you. If you are using Legacy speakers, the Legacy crew already knows how to program the unit for optimal performance in your system. If you are using other speakers – and indeed you can use the Wavelet II with non-Legacy speakers – you would need to supply information, such as crossover frequencies, so that they can program the unit properly.

For example, to work with my Legacy Signature speakers, two pairs of channels are set for bi-amping (L-R for highs and L-R for lows); another pair is set as full range L-R in case I didn’t want to bi-amp; and the final pair is reserved for subwoofers(s). Higher-end Legacy speakers, such as the Valor, would use all four pairs of channels for the different sections of the speakers, i.e., multiamping. If I later trade in my Signatures in favor of some other speakers, I can return the Wavelet II to Legacy for reprogramming as needed.

By the way, for those deep in the weeds on crossovers, note that Wavelet II digital crossover is itself quite sophisticated, supporting multiple parameters (slopes, delays, filters, etc.) per channel.

Room Correction: Certainly, there are other room correction systems (rather a misnomer, as it’s more like “room adaptation”), whether from makers of receivers or independent ones such as Dirac, but Legacy is the only vendor I know of offering the Böhmer system.

The Böhmer approach differs from most, perhaps all, other room correction systems in that it is primarily based on time rather than frequency, compensating for room effects within a 50 millisecond (ms) window. That long window – in audio processing terms, 50 ms is a long time – allows the Böhmer analysis to “look at” and deal with the results of multiple room reflections.

To cover the process in any detail would take us far afield; I’ll stick to reporting the results below, and suggest that you look at the detailed Böhmer website for more information.

Creating the correction algorithm for any given audio system and room is computationally intensive, so during setup you run a measurement process and the data thus collected is submitted via the internet to a high-powered server. Within a few minutes, the calculated correction algorithms are sent back to the Wavelet II. Although execution of the algorithms while playing music requires less processing power than their initial construction, the load is hardly trivial, which is why the Wavelet II contains a serious numerical processor (an Analog Devices chip with associated hardware support components).

Other DSP: Room correction is the most obvious form of DSP, but the Wavelet II offers another, or rather two others: “Omnio” and “Omnio+”. These are Legacy’s names for algorithms that “improve channel separation and restore the directional vector relationship to depth and position cues”. As the names imply, Omnio, which has been around for a few years, was the first iteration; “Omnio+” is a matter of months old, having been added in the recently released version 2.0 of the Wavelet II firmware.

Note that existing Wavelet II’s can be upgraded with this latest firmware; in other words, the functionality of the Wavelet II can improve after you buy it. We’re used to that with smartphones (and electric vehicles); how nice to see it in an audio product.

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So what’s the result? What does advanced DSP do for the sound? Does it improve our listening experience? Part 2 of this article has now been published here.