May 15, 2024

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 ( and Audioholics ( — and stash away some savings; Nirvana may be near!


*A Linkwitz–Riley filter (–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…

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Meet the Staff

Meet the Staff
John J. Puccio, Founder and Contributor

Understand, I'm just an everyday guy reacting to something I love. And I've been doing it for a very long time, my appreciation for classical music starting with the musical excerpts on the Big Jon and Sparkie radio show in the early Fifties and the purchase of my first recording, The 101 Strings Play the Classics, around 1956. In the late Sixties I began teaching high school English and Film Studies as well as becoming interested in hi-fi, my audio ambitions graduating me from a pair of AR-3 speakers to the Fulton J's recommended by The Stereophile's J. Gordon Holt. In the early Seventies, I began writing for a number of audio magazines, including Audio Excellence, Audio Forum, The Boston Audio Society Speaker, The American Record Guide, and from 1976 until 2008, The $ensible Sound, for which I served as Classical Music Editor.

Today, I'm retired from teaching and use a pair of bi-amped VMPS RM40s loudspeakers for my listening. In addition to writing for the Classical Candor blog, I served as the Movie Review Editor for the Web site Movie Metropolis (formerly DVDTown) from 1997-2013. Music and movies. Life couldn't be better.

Karl Nehring, Editor and Contributor

For more than 20 years I was the editor of The $ensible Sound magazine and a regular contributor to both its equipment and recordings review pages. I would not presume to present myself as some sort of expert on music, but I have a deep love for and appreciation of many types of music, "classical" especially, and have listened to thousands of recordings over the years, many of which still line the walls of my listening room (and occasionally spill onto the furniture and floor, much to the chagrin of my long-suffering wife). I have always taken the approach as a reviewer that what I am trying to do is simply to point out to readers that I have come across a recording that I have found of interest, a recording that I think they might appreciate my having pointed out to them. I suppose that sounds a bit simple-minded, but I know I appreciate reading reviews by others that do the same for me — point out recordings that they think I might enjoy.

For readers who might be wondering about what kind of system I am using to do my listening, I should probably point out that I do a LOT of music listening and employ a variety of means to do so in a variety of environments, as I would imagine many music lovers also do. Starting at the more grandiose end of the scale, the system in which I do my most serious listening comprises Marantz CD 6007 and Onkyo CD 7030 CD players, NAD C 658 streaming preamp/DAC, Legacy Audio PowerBloc2 amplifier, and a pair of Legacy Audio Focus SE loudspeakers. I occasionally do some listening through pair of Sennheiser 560S headphones. I miss the excellent ELS Studio sound system in our 2016 Acura RDX (now my wife's daily driver) on which I had ripped more than a hundred favorite CDs to the hard drive, so now when driving my 2022 Accord EX-L Hybrid I stream music from my phone through its adequate but not outstanding factory system. For more casual listening at home when I am not in my listening room, I often stream music through the phone into a Vizio soundbar system that has tolerably nice sound for such a diminutive physical presence. And finally, at the least grandiose end of the scale, I have an Ultimate Ears Wonderboom II Bluetooth speaker for those occasions where I am somewhere by myself without a sound system but in desperate need of a musical fix. I just can’t imagine life without music and I am humbly grateful for the technology that enables us to enjoy it in so many wonderful ways.

William (Bill) Heck, Webmaster and Contributor

Among my early childhood memories are those of listening to my mother playing records (some even 78 rpm ones!) of both classical music and jazz tunes. I suppose that her love of music was transmitted genetically, and my interest was sustained by years of playing in rock bands – until I realized that this was no way to make a living. The interest in classical music was rekindled in grad school when the university FM station serving as background music for studying happened to play the Brahms First Symphony. As the work came to an end, it struck me forcibly that this was the most beautiful thing I had ever heard, and from that point on, I never looked back. This revelation was to the detriment of my studies, as I subsequently spent way too much time simply listening, but music has remained a significant part of my life. These days, although I still can tell a trumpet from a bassoon and a quarter note from a treble clef, I have to admit that I remain a nonexpert. But I do love music in general and classical music in particular, and I enjoy sharing both information and opinions about it.

The audiophile bug bit about the same time that I returned to classical music. I’ve gone through plenty of equipment, brands from Audio Research to Yamaha, and the best of it has opened new audio insights. Along the way, I reviewed components, and occasionally recordings, for The $ensible Sound magazine. Most recently I’ve moved to my “ultimate system” consisting of a BlueSound Node streamer, an ancient Toshiba multi-format disk player serving as a CD transport, Legacy Wavelet II DAC/preamp/crossover, dual Legacy PowerBloc2 amps, and Legacy Signature SE speakers (biamped), all connected with decently made, no-frills cables. With the arrival of CD and higher resolution streaming, that is now the source for most of my listening.

Ryan Ross, Contributor

I started listening to and studying classical music in earnest nearly three decades ago. This interest grew naturally out of my training as a pianist. I am now a musicologist by profession, specializing in British and other symphonic music of the 19th and 20th centuries. My scholarly work has been published in major music journals, as well as in other outlets. Current research focuses include twentieth-century symphonic historiography, and the music of Jean Sibelius, Ralph Vaughan Williams, and Malcolm Arnold.

I am honored to contribute writings to Classical Candor. In an age where the classical recording industry is being subjected to such profound pressures and changes, it is more important than ever for those of us steeped in this cultural tradition to continue to foster its love and exposure. I hope that my readers can find value, no matter how modest, in what I offer here.

Bryan Geyer, Technical Analyst

I initially embraced classical music in 1954 when I mistuned my car radio and heard the Heifetz recording of Mendelssohn's Violin Concerto. That inspired me to board the new "hi-fi" DIY bandwagon. In 1957 I joined one of the pioneer semiconductor makers and spent the next 32 years marketing transistors and microcircuits to military contractors. Home audio DIY projects remained a personal passion until 1989 when we created our own new photography equipment company. I later (2012) revived my interest in two channel audio when we "downsized" our life and determined that mini-monitors + paired subwoofers were a great way to mate fine music with the space constraints of condo living.

Visitors that view my technical papers on this site may wonder why they appear here, rather than on a site that features audio equipment reviews. My reason is that I tried the latter, and prefer to publish for people who actually want to listen to music; not to equipment. My focus is in describing what's technically beneficial to assure that the sound of the system will accurately replicate the source input signal (i. e. exhibit high accuracy) without inordinate cost and complexity. Conversely, most of the audiophiles of today strive to achieve sound that's euphonic, i.e. be personally satisfying. In essence, audiophiles seek sound that's consistent with their desire; the music is simply a test signal.

Mission Statement

It is the goal of Classical Candor to promote the enjoyment of classical music. Other forms of music come and go--minuets, waltzes, ragtime, blues, jazz, bebop, country-western, rock-'n'-roll, heavy metal, rap, and the rest--but classical music has been around for hundreds of years and will continue to be around for hundreds more. It's no accident that every major city in the world has one or more symphony orchestras.

When I was young, I heard it said that only intellectuals could appreciate classical music, that it required dedicated concentration to appreciate. Nonsense. I'm no intellectual, and I've always loved classical music. Anyone who's ever seen and enjoyed Disney's Fantasia or a Looney Tunes cartoon playing Rossini's William Tell Overture or Liszt's Hungarian Rhapsody No. 2 can attest to the power and joy of classical music, and that's just about everybody.

So, if Classical Candor can expand one's awareness of classical music and bring more joy to one's life, more power to it. It's done its job. --John J. Puccio

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"Their Master's Voice" by Michael Sowa

"Their Master's Voice" by Michael Sowa