In case you need more reasons to start following the SoundStage! YouTube channel, know that, occasionally, some of the vlog-type videos posted there can get pretty spicy. No, I don’t mean X-rated stuff; I’m talking about SoundStage! founder and publisher Doug Schneider’s July 8 Real Hi-Fi video in which he discusses the shortcomings of single-driver speakers. Putting it plainly, “they’re crap,” he says. To my amazement, of the 40 or 50 comment chains on that video (as of this writing), only 11 of them are people letting Doug know he’s an idiot and wrong about everything. Of those, I think only two used profanity, and no one used the caps-lock key. Bravo, internet! Faith in humanity restored!

Joking aside, Doug made some really good points in that video, and the general consensus seems to be agreement with him. And for good reason—there’s been quite a lot of real science done over the years that explains how loudspeaker drivers work and why asking a single dynamic cone driver to reproduce the full audioband, from 20Hz to 20kHz, just isn’t in the cards. It comes down to the laws of physics, and try as you might, you can’t beat ’em. A full-range driver is going to struggle to play at the extremes of the audioband, and any attempt to ameliorate the problems at one end will just exacerbate them at the other.

I know this because I’ve read all about the physics of loudspeakers. Actually, it was Doug who recommended I read the Loudspeaker Design Cookbook by Vance Dickason—a book that’s sitting at my bedside right now, by the way—and Floyd Toole’s Sound Reproduction. Doug sometimes gets to hang out and chat with the very acousticians and designers whose work paved the way for this knowledge, so I’m confident that they’re on the same page about the operating principles of dynamic cone drivers. The science behind Doug’s arguments that explains why single-driver speakers don’t work well is compelling.

But I like to play devil’s advocate. Here’s what I think is wrong with this way of thinking.

Hi-fi is about entertainment. There is, factually, nothing about speakers or headphones or plastic discs that is necessary to sustaining life or the functioning of civil society. We do this stuff because we want to, and the impassioned cry of “I just couldn’t live without a good system!” that is common to all audio enthusiasts illustrates that we really, really want to.

In entertainment and the arts, what we want and what we like isn’t necessarily governed by reason. Sure, there are often practical considerations, but beyond having basic wants and needs met, judgments are made primarily by how something makes us feel. In hi-fi, there might be certain constraints (“I want to minimize the number of components on my shelf”; “I have a room with such-and-such dimensions, and the speakers need to fit over there”; “I have no space for a subwoofer, so I need full-range main speakers”; etc.), but once products have been narrowed down using practical considerations, “I like the finish on this one better than the others” is good enough a reason to buy something over its competitors.

There’s a certain romanticism, a retro-cool vibe, and a joy of ownership that comes with certain audio products that explains their continued popularity in spite of their status as outmoded tech. An obvious example is tube amplification. Specialty speakers, those with unusual designs that may require atypical setups or amplification, are another. I count single-driver loudspeakers among them, along with difficult-to-drive planars, über-high-efficiency horns, and open-baffle speakers. And I won’t even start on the topic of the wonderfully satisfying but deeply imperfect vinyl playback craze. There are myriad reasons for liking this stuff, and they’re all personal. The continued popularity of products like these is proof that hi-fi is, in an almost radical way, about an individual’s enjoyment over all other considerations.

This has led me to think that one of two hypotheses must be true: either we have uncovered some odd bias that reviewers are uniquely prone to, or there may be something about single-driver speakers that some people find more pleasing than the technically more accurate multi-driver affairs that dominate the market.

You can’t always get what you want

First, as reviewers—and especially as reviewers at SoundStage!, which has attained a reputation for actually measuring the components under review—there is sometimes a perceived obligation to be as authoritative with subjective experiences as one is with objective facts. I am as guilty of this as anyone. I’ve found myself balancing my personal, sometimes niche, preferences with objectively high-performing gear in my own system and, to some extent, the gear that I review. I was reminded of SoundStage! Access editor Dennis Burger, whose editorial and corresponding podcast from a while back discussed how he reviews gear and why the system he uses probably isn’t what he’d use if he weren’t an audiophile reviewer. What it comes down to is that reviewers have different needs than the typical consumer.

I wanted to get to the bottom of this, so I asked Dennis if there has ever been some piece of gear that he really loved, but couldn’t use in his reviews. “I really loved the Denon PMA-150H,” he told me, “but I couldn’t use it as a reference because it just won’t drive three-way towers with any sort of impedance dip without thinning out in the bass.” Dennis, like me, is a fan of handing over the lowest octaves to a subwoofer, which can potentially save the amp a lot of the heavy lifting. In other words, Dennis’s preferred use of the PMA-150H is different from that of most hi-fi enthusiasts, so he elected not to use it in his review system. His system is set up so that it’s maximally useful in communicating to him what works well and what doesn’t about a product, not necessarily in being maximally enjoyable to him. The Denon, which needed a bit more oomph into low impedances, couldn’t quite make the cut. But if Dennis could’ve expected most readers to have a subwoofer in their systems, things might’ve been different. “If 2.1-channel speaker setups were accepted as the norm, it would have been my reference piece until it croaked, because I loved a lot about it otherwise,” he said.

Is the little Denon integrated amplifier the same sort of audiophile exotica as a single-ended triode amp or a pair of single-driver loudspeakers? Of course not, but the point is that hi-fi reviewers might tend, perhaps subconsciously, to prefer the sort of gear that suits their systems and reviewing style. When you stake your reputation and your livelihood on being trustworthy, you may tend toward tools with proven performance, i.e., stuff that measures well. I wonder if this is a bias that influenced Doug’s thoughts on single-driver speakers.

I followed up with Dennis on this topic, in an oblique way. What makes a reviewer seem credible? He said, “when I’m reading a review, I’m looking for clues that the reviewer understands how the gear works. If I sense a sort of ‘let’s hook this up and see what happens’ spookiness, I know the review probably isn’t for me.” Aha. So for Dennis, some level of objectivity is necessary. And a reviewer certainly ought to know their stuff, it’s true. Factual dishonesty and BSing are certainly offenses that merit a loss of credibility. At no point, however, did Dennis stress that the ability to communicate an experience or a feeling was important. And that’s A-OK! The point is that reviewers hold certain values that they apply to evaluating gear, and for Doug and Dennis, single-driver speakers, electronics with tubes, and, until recently, turntables, aren’t the sorts of things that jive with those values. “Guru”-type reviewers, whose understanding of the gear, their audience, and their purpose as a communicator differ from Doug’s and Dennis’s, would take a totally different approach.

There are many ways to skin a cat, but you still have to choose one

Not everyone is going to be able to dive headfirst into the strange stuff, and I get that. But it’s worth investigating why those who prefer the less-orthodox gear, specifically single-driver speakers, do so. If I can tackle the topic in a way that appeals more to the crowd who likes to know how something works, rather than preaching to the choir—that is, those who’ve already drunk the single-driver Kool-Aid—all the better.

The design of a single-driver loudspeaker system makes compromises, like all loudspeakers, but single-driver speakers can compromise in a way that might be considered minimally intrusive. In his video, Doug mentioned having heard a pair of single-driver speakers from Poland’s Cube Audio, and was impressed enough to allow that they’re “decent for products of that type.” The Cube Audio products are an ideal example of purposefully directed engineering intended to maximize the single-driver concept. Cube Audio’s top-shelf drivers boast optimized magnet, pole piece, and voice coil geometry, constructed to remarkably tight tolerances. The company also claims its proprietary suspension and cone designs are exceptionally linear. The drivers are understandably quite expensive, but the result is a single driver with a wide bandwidth and low distortion.

The problem of frequency response and bandwidth is a common criticism of single-driver designs. While it’s true that a single driver just can’t cover the entire audioband, consider that in most source material, there is very little content below about 100Hz or above 12kHz. A fact I like to throw around because it perturbs audiophiles, many of whom have little experience in musical performance, is that the fundamental tone of the low E on a four-string electric bass or standup bass is 41Hz, a full octave higher than the 20Hz that is often considered the ideal -3dB point in a loudspeaker system. The way we hear and perceive such notes means that we are much more sensitive to higher-frequency harmonics of the fundamental—harmonics that are often louder than the fundamental as created by these instruments. A similar story may be told about the highest octaves, from around 10kHz and up. We can hear these tones, and an accurate reproduction of them is important for a loudspeaker to perfectly reproduce the timbre of instruments like cymbals, but there just isn’t a lot of sound up there to reproduce. From a psychoacoustics perspective, a single full-range driver could be perfectly adequate in the reproduction of a wide variety of music.

Distortion is another oft-cited criticism of single-driver speakers. I’ll argue that this could, in a way, be seen as a strength rather than as a weakness. At reasonable listening levels, single-driver speakers generate mostly second- and third-order harmonic distortion. While audible, these types of distortion are easily masked by the source material. And since single-driver speakers poop out in the upper octaves, the more noticeable harmonic distortion in the higher frequencies isn’t reproduced very loudly. Not to mention that full-range drivers are designed to maximize their pistonic behavior and minimize harsh cone breakup modes—recall all the engineering that went into the Cube Audio drivers. This also means that within their limits, there aren’t a lot of opportunities for intermodulation distortion, either. And of course, there are no other drivers to interfere with or crossover components to cause weird phase things.

The lack of a crossover and other drivers is touted as one of the greatest benefits of single-driver speakers. I think this is where woo-woo and good engineering get confused with one another. A poorly designed crossover can introduce a lot of audible problems. What if that just wasn’t a factor? Sure, this shifts more importance onto the design of the driver, the enclosure, and the baffle, but it removes a potential problem area from the design. While a two- or three-way speaker with a masterfully designed crossover can sound rightly amazing, for some people the sound of not having any crossover at all may be preferable, even if not as technically accurate. Again, who’s to say?

Singled out

By now you may have noticed that I haven’t given my own personal thoughts on the subject. The fact is, they’re a bit nuanced. I generally tend toward Doug’s and Dennis’s side of things, but I remain skeptical of the skeptics. Speakers, and other gear that measures exceptionally well, are reference points for a reason, and they can tell us a lot about what makes for good sound. But I remain curious about the likes of tubes, horns, and indeed, single-driver speakers. I want to know what it is about technically imperfect or strange gear that people find so compelling; I want to understand the experiences these devices create and why and how they do it. My interest in hi-fi has always stemmed from the way different technologies can create in us different subjective experiences.

It seems that Dr. Slawa Roschkow, the founder, director, and chief engineer of SW1X Audio Design, shares a similar philosophy to mine. In Roschkow’s YouTube video, which Doug mentioned as a source of inspiration for his own comments, he discusses several of the ideas I mentioned above in my defense of single-driver loudspeakers—though, bear in mind, I’m agnostic on this issue, while Dr. Roschkow has an interest in selling these sorts of things. In addition to several single-driver, crossoverless speakers, SW1X also manufactures tube amplifiers, preamps, and even an array of digital audio products, including DACs, streamers, and transports, that all incorporate 70-plus-year-old vacuum-tube technology. Dennis and Doug both feel queasy just thinking about this stuff. I love it, and I hope to get to hear some of it one day.

Maybe I should get a pair of single-driver speakers, or an exotic filterless DAC, or some bizarre tube amp. Maybe I’ll really fall in love. Maybe I just have a problem with authority and like pissing off my boss, who might prefer it if I weren’t so interested in these things. But in any case, I think “wrong” audio gear has a lot of value, even though it sometimes can be overshadowed by its more obvious shortcomings. Simple isn’t always better, but it is simpler, and simplicity is worthy in its own right. Maybe it’s time to give the weird stuff a chance.

. . . Matt Bonaccio
mattb@soundstage.com