Interview with Jon Herron of Wisdom Audio

May 19, 2010


Jon Herron of Wisdom Audio was gracious enough to consent to an exclusive interview with the Ultra High-End Audio and Home Theater Forum which is set forth below. Special thanks go to Neil Davidson of Genesis Technologies for assisting with arranging the interview and for agreeing to help provide answers to any follow-up questions.

Thank you for agreeing to be interviewed for the Ultra High-End Audio and Home Theater Review. Perhaps we could start off with a technical question: would you explain the difference between Wisdom Audio’s planar-magnetic speakers and electrostatic speakers like those of MartinLogan and ribbon and quasi- ribbon speakers like those of Magnepan?

Our planar magnetic devices are conceptually quite like the “quasi-ribbons” that Magnepan makes. Because of the potential for confusion between “ribbon,” “true ribbon” (which is the same thing), and “quasi-ribbon” (which is actually quite different), we try to avoid using the term “ribbon” entirely.

Here’s a short explanation: electrostatic, planar magnetic, and (true) ribbon drivers all eschew traditional cones and domes in favor of a thin-film, low mass, force-over-area approach.

• Electrostatics use the same force that makes your socks stick together in the dryer, placing the film between charged grids. A static (unchanging) electrical charge is placed on the film itself. The audio signal is then placed on the grids, modulating their charge to push and pull and film one way or the other.
• Planar magnetics use magnets instead of a charged grid, in front of and behind the film. The voice coil is actually on the film itself, and interacts with the magnetic field to make the film move. Thus they are similar to electrostatics, except that they use magnetism rather than electrostatic forces to make the film move.
• A “true” ribbon places the magnets along the edges of a strip of metal foil, usually aluminum. The foil is usually corrugated and is attached only at the ends, and is itself the conductor of electricity.

If anyone in the forum wants more detail than we have space for here, we have a fairly detailed white paper on this subject on our website.

What are the advantages of planar-magnetic speakers over other types of speakers?

I usually sum it up in terms of dynamics, detail and distortion.

Our planar magnetic devices (PMDs) use powerful neodymium magnets to control the movement of an incredibly low-mass, thin film diaphragm. There simply is not much inertia to blur the musical signal. Controlled by the powerful magnetic field, the film pretty much does what it is told to do, reproducing both micro- and macro-dynamics effortlessly, revealing a tremendous amount of detail with lower distortion than we are accustomed to hearing from traditional cones and domes.

Our PMDs are quite sensitive (between 90 and 97 dB for 2.83V in, varying by model). They can also handle a tremendous amount of power, since the voice coil is fully exposed to the air. Heat radiates away from the film almost instantly. For example, our flagship L150i uses a six foot tall planar line source that can handle well over 1000 watts. The long PMD reproduces everything from 275 Hz up, to beyond the audible range.

Your speakers have always been integrated with a subwoofer module and employed an electronic “brain” to tune the speakers specifically to a given listening room. Would you describe the evolution of the “brain” from an analog unit, to a digitally- controlled analog unit, to a fully digital unit based on Audyssey?

Wisdom Audio has always felt that building a state-of-the-art loudspeaker without accounting for the problems introduced by the room itself is hopelessly naïve. Rather than leave it entirely to chance, early Wisdom speakers were usually set up by factory personnel, and used extensive parametric EQ to compensate for the adverse effects of the particular room. The goal was to deliver not only a better result, but a more consistent result from one customer’s home to the next.

The original “brain” was completely analog, and used dozens of DIP switches to effect the changes in the crossover and the parametric filters. This was a user-interface nightmare, but allowed us to switch high-precision parts in and out of the circuit as needed to effect a change.

The DCAB-1 introduced digital control over an entirely analog signal path. (Hence “Digitally Controlled Analog Brain,” or DCAB.) This was set up using a PC and a terminal emulation program, and provided greater flexibility and perfect repeatability of settings. It was a big improvement over the original analog brain. It was still a bit complex to set up and (as with all parametric EQ) it required a highly experienced person at the controls to get proper results. Good room EQ isn’t easily accomplished. You have to know which problems to tackle, and which are better left alone. (I know Keith Yates is on this forum. Ask him about room EQ. He frequently spends several days dialing in the final parameters of a single system.)

The SC-1 System Controller used in our current systems ups the ante is a few ways. It is a balanced 7.3 in, 14.3 out electronic crossover; it also provides model-specific parametric EQ; and it includes Audyssey Labs’ MultEQ XT room correction. All Sage Series are biamplified, so all Sage systems must have an SC-1, and therefore also include room correction. But the SC-1 is a dream to use compared to our older products. Much, much more straightforward, and it makes it much easier for our dealers to achieve consistently excellent results.

What target curve do you employ with Audyssey?

We have our own target curves. There are four curves available, two of which are unique to Wisdom Audio SC-1-based systems: the standard Wisdom curve, and the Wisdom Gaming curve (which is the same except for several extra dB below 35 Hz).

Can the Audyssey unit be used with your legacy speakers?

In principle, there isn’t any reason why not. There hasn’t been any call for it as yet (people are generally pretty happy with their existing Wisdom systems), so we have not done some of the programming work that would be required. But the SC-1 has more than enough flexibility, and supports anything from 2.0 up to 7.3 channel systems.

For years, your trademark has been tall freestanding line source speakers. In 2004, you changed to a somewhat different model emphasizing smaller in-wall and on- wall speakers when you introduced the Sage Series. Can you tell us about the factors leading to such change?

Actually, the Sage Series started shipping in 2008. Most of this series is available as in-wall, on-wall, or freestanding models, and we have several line sources in the line. But we have found that the people who can afford luxuries such as our speakers are increasingly reluctant to compromise the appearance of their home for the sake of the performance of the system. What most people want is the performance of a big floorstanding speaker, without having to give up all that space, or compromising their décor.

We identified this gap in the market as a significant opportunity. Until the Sage Series was introduced, there really wasn’t an architectural product line that could compete with the finest freestanding speakers. Now there is.

As to size: line sources must be quite tall, by their nature. Not everyone wants to have a 2m speaker in the room — especially in a smaller room. So we created new PMDs in a smaller form factor that would behave as point sources. It’s just a matter of giving people the performance they want, in a form factor that they will welcome into their homes.

Having said that, line sources do have some real advantages. The sound radiates into the room as an expanding cylinder (rather than as an expanding sphere). This fact largely eliminates the ceiling and floor reflections that are so deleterious to good sound. The energy from the speaker is kept in the plane where your ears are likely to be, so you hear more of the speaker and less of the room.

Another benefit is in more uniform SPL throughout the listening area. Technically, the sound falls off 3 dB per doubling of distance, rather than the usual 6 dB/DD. This is a more striking difference than the number might suggest. You can be at the back of a room with the music playing quite loudly, and walk right up to the speakers without them seeming to get significantly louder. With normal point sources (including those we make), repeating this experiment results in things being uncomfortably loud as you approach the speakers.

What this means is that whether you are in the front room or the back row, you get much the same experience as the person sitting in the money seat. Every seat in the house is better.

One of the advantages of planar-magnetic speakers you mentioned above is their cylindrical radiation pattern. While that has a distinct advantage for horizontal dispersion, vertical dispersion traditionally has been limited. How do you overcome the vertical dispersion limitation in your Sage line of speakers with fewer planar-magnetic elements?

The primary determinant of radiation pattern is the size of the driver relative to the wavelength being produced. Whether or not the transducer is a PMD has little to do with it, except that we can build PMDs in shapes that are impractical for cones and domes.

We have both 48” and 72” tall line sources. As long as your ears are somewhere between the ends of the line vertically, you are in good shape sonically. In fact, there is remarkable consistency between standing up and sitting down, far greater than with multi-driver systems.

Our smaller speakers radiate sound as point sources, which is to say that the sound spreads into the room as an expanding sphere (rather than as a cylinder). Their vertical dispersion is actually better than many traditional speakers because our PMDs can be crossed over at a much lower frequency. The tweeter in the P20, for example, is handling everything above 650 Hz— a full two octaves more than a typical 1” dome tweeter.

The common audiophile wisdom has been that in order to create a soundstage with depth, you should locate your speakers well away from the rear wall. Is this a myth? If not, how do you create the illusion of soundstage depth with your in-wall and on-wall speakers?

I love it when someone says that before I demo our in-wall speakers.

So, here’s the deal. As your members know, you cannot get good soundstaging without first having a great speaker. There are plenty of speakers that will never reproduce great depth and image focus, no matter what you do. So let’s stipulate that we are talking only about great speakers that have the ability to image well. Then the question becomes, how do you maximize their performance in this regard?

Most audiophiles understand that speaker placement is critical in this regard. Careful positioning, well out away from all the walls, seems to work the best. But why it this true?

I contend that there are at least two room-specific factors that are being optimized with this careful room placement: matching the frequency response and minimizing early reflections.

The room itself introduces large response aberrations in any speaker. Careful placement, including attention to symmetry, can minimize the resulting differences between left and right speakers. Without good left-to-right matching, all bets are off for good image focus. Our room correction does a better job of matching the real response in the room between speakers than anything you can do with placement alone. (Though, as with any EQ, it works best when it has the least to do. It’s not a panacea for a bad room. But it is a powerful tool.)

Soundstage depth is easily impaired by early reflections from the wall behind the speakers and the side walls. These early reflections are delayed by a few milliseconds, and confuse the ear-brain mechanism as to where the sounds should appear to be. Moving the speakers well out into the room delays the reflections more, and reduces their amplitude (since they have traveled that much further). Hence the traditional wisdom: move the speakers and the listener far away from the walls.

But think about it: if the speaker is physically part of the wall itself, there are no delayed reflections to minimize. Okay, it is still good to minimize side wall reflections using some diffusion and/or absorption. But the front wall reflection is simply gone.

In this regard, in-wall speakers actually have some advantages over freestanding ones.

I travel with our L75i in portable demo walls. (Yes, I travel with six foot tall in-wall speakers and a couple road cases of electronics.) People are always amazed at the depth they reproduce when just set up against the dealer’s wall. If there is depth in the recording, it is reproduced

If I remember correctly, prior to 2007, a member of Wisdom Audio’s staff personally installed and fine-tuned the speakers for each individual customer. I understand your speakers are now installed though a network of dealers. Would you tell us what criteria you use in selecting your dealers and what training they receive?

Actually, the Audyssey system is a large part of why we can appoint dealers to do what factory personnel were previously obligated to do in the field. We can train a good dealer on how to get consistently terrific results in as little as a couple hours. Whereas with the older systems, very few dealers had the time or expertise to really master the arcane world of proper room EQ — so we wound up doing it ourselves.

In North America, either Todd Sutherland or I appoint our dealers. We do not use reps, and we do all the training ourselves. Unfortunately, having only two people for the entire continent makes it a slow process. But we select dealers who are passionate about high quality audio and who have real installation experience and skill.

We deliver training in the dealer’s own store, on their demo system. Between the initial demo and subsequent sales and installation training, dealers see quite a lot of us during the startup period. We also offer in-depth training seminars in our factory in Carson City, Nevada. These include the opportunity to hear a wide range of different models in a relatively short period of time. We designed our sound room with modular wall segments that allow us to swap out any in-wall or on-wall speakers quickly and fairly easily. And of course we can carry in any of the freestanding speakers on a moment’s notice. I’ll include a photo of the room set up with our L150i speakers in case you want to post it.

Finally, one last question: the apparent trend among high-end loudspeaker manufacturers is to introduce new statement speakers costing well in excess of $100,000. Can we expect Wisdom Audio to follow suit and introduce an Audyssey controlled version of the Infinite Wisdom Grande?

The Sage Series covers a pretty wide range as it is, from about $15,000 to well over $100,000 for a large scale multichannel system. But I understand you are wondering whether we might introduce a speaker in the six-figure range for a single pair.

I think it is unlikely that we will ever build anything on the physical scale of the Infinite Wisdom Grande. At about 4m tall, it was quite a statement of technology, but not terribly practical. We are more interested in delivering unsurpassed performance in aesthetically pleasing physical packages.

Our latest PMDs are the finest the company has ever designed and manufactured, period. They are also more affordable (though certainly not inexpensive) than some of the past designs. Is there significant demand for something even more ambitious? Probably. But we are quite happy with the performance we are delivering right now, with the Sage Series.

Again, thank you for taking the time to participate today.