Monthly Archives: May 2012

Kids these days….

Dear Ken,

The thread at Senior Haus at MIT which is my daughter’s dorm for a few years had this on it recently:

———- Forwarded message ———-

From: daniel e mcanulty
Date: 2011/12/3
Subject: Re: Because this was too good not to share.
To: xxxxxx;
Cc: xxxxxx;

Oh hey, this reminds me that I was surprised and pleased to find that a haus resident from the 70s works upstairs from me, the founder and main-brains behind ZT amps, through which you can see wilco playing here:

They’re these tiny but great sounding amps. Ken’s site can be found here:

To get a chance to hang out, he took me to (yet another!) old bay area senior house resident’s show at SFMOMA,

and it was awesome. Not only was campbell’s work great, but being driven around by a cantankerous old Ken who would curse out anything and everything he thought was wrong with the world under his breath really took me back, except kind of back to the future, seeing him and Jim (and yet another old house resident whose name I forget) interact at sfmoma, it was like seeing all of my friends cast forward into the future, where we are all exactly the same, only older and slightly more authoritatively foul-mouthed.

It really made my heart explode a little, I’m not kidding.

Here, the Red Hot Chili Peppers’ guitarist can be seen jamming backstage through one of Ken’s tiny little amps, playing effectively against a bassist and drummer with something the size of a lunch box:

Nobody knows how to advertise anymore, least of all cantankerous old senior housers who would rather not interact with the world as-it-is, so if you’re into playing music with a small and very-loud amp and want to support a haus company, check out zt amplifiers:

They’re about to come out with a newer larger one as well, I can literally hear them upstairs putting the new design through the paces.

Anyway, it makes me smile to remember my heart exploding. It’s good, and is good, and is, daily daily,


ps jim campbell’s installation is really quite nice:



#1.  Old?

#2.  The other ancient compatriot was the renowned artist, Alan Rath.

#3.  So, my company is barely three, has negligible marketing budget; Wilco, ZZ Top, Sonic Youth, The Bunnymen, MGMT, The Chili Peppers, Merle Haggard, Andy Summers, Brian Wilson, Jason Newsted, Leon Russell, Cirque Du Soliel, John Oates, Jim Messina, Robert Poss, Oliver Leiber, John Platania, Yuka Honda, Geza X, etc, etc, are doing gigs and TV shows with the amps.  Not to mention print features from Rolling Stone to Wired. But, thanks for any advertising pointers you may have for me.

#4. Old??

Seriously… nice to meet you, Dan!

Some Unsorted Assorted Songs.


These were recorded in my home, ca. 1991 if memory serves. In general, I play all instruments except drums. Unless the drums suck, then that’s me, too. Lots more, and different styles, to come as I figure out a better workflow for posting.

All Songs (c)2013

No Reason Only Rhyme


DSC01224 DSC01410 DSC01423 IMG_5257 DSC00566 DSC00904 DSC01209DSC05093DSC04627DSC04994DSC05055DSC05080DSC01456DSC01513DSC01538DSC01547

NY Times, 1985…..

From the New York Times, 1985.  25 years. 
July 14, 1985



Reinventing the wheel has become a metaphor for redundancy. Reinventing the loudspeaker, by contrast, occasionally leads to valid innovation.

The reason, I suppose, is that the wheel – assuming it is really round – can’t be much improved. Loudspeakers can, and lately a few venturesome engineers have made a stab at it.

Such attempts may involve imaginative departures from established norms, as in the case of the Acoustic Research MGC-1 and the dbx Soundfield 10 – two new models that were sounding forth with notable eclat at last month’s Consumer Electronics Show in Chicago. Both designs represent new ways of dealing with one of the oldest and most recalcitrant problems in sound reproduction -the question of ambiance.

The problem is fundamental and arises from the fact that playing orchestral music in the living room is obviously unnatural. Orchestral sound is conceived with the aura of large spaces for the simple reason that no other kind of space could accommodate a hundred musicians plus their audience. The reverberant character of the concert hall is therefore implicit in symphonic music – an inseparable aspect of the sound imagined by the composer as he wrote the score. When such music is played via records or radio within the narrow confines of the living room, a contradiction develops between sonic and architectural dimensions. These new speakers – each in its own way – try to resolve this contradiction.

In the case of the Acoustic Reseach MGC-1 – a design developed by the former M.I.T. psychoacoustics researcher Ken Kantor – a sizable enclosure (25 inches high by 26 inches wide by 16 inches deep) actually houses two separate speaker systems. One projects the sound toward the listener while the other, set at an obtuse angle, directs the sound toward the nearest side wall. The speakers aimed at the listener are quite narrowly focused. You might say that they ”shine” the sound at the hearer the way an automobile headlight points the light directly ahead in a tight beam. This pattern of sound radiation conveys a precisely defined aural image of the musicians’ various locations on the imaginary stereo stage.

Such narrow sound projection normally entails a major drawback: It yields a hard, tight, even strident sound, bereft of the feeling of ambiance. But when supplemented by the speakers aiming at the wall, this liability dissolves, and the sound assumes a natural spaciousness, without losing the precise definition of the player’s location. In the past, spaciousness of sound and precise stereo imaging have been mutually exclusive design options. Now Acoustic Research appears to have found a way to have the acoustic cake and eat it, too.

One striking effect of this unique speaker is the apparent enlargement of one’s living room. As the music starts, the walls of the room seem to recede to form an aural environment as capacious as a concert hall. This is not done by wall reflection alone. The trick is accomplished by a special delay circuit, which holds back the sound for the sideways speakers by about 0.02 second – roughly the time it would take for the sound in a fair-sized hall to reach a listener near the center after bouncing off the side walls. In other words, this speaker contains integrally the kind of ambiance-enhancement that is usually available only as a separate add-on device for highly elaborate sound systems. The result is an uncanny trompe l’oreille which transforms a residence into an auditorium, especially if you close your eyes.

Initial impressions gained at the Chicago show left no doubt that the Acoustic Research MGC-1 – quite aside from its ability to suggest ample aural space while maintaining precise stereo imaging – is a speaker of splendid fidelity, capable of doing full justice to any kind of music. And so it should, what with a price tag of $3,600 per pair for the walnut version, or $7,100 if your taste runs to rosewood.

Acoustic Suspension Issues.

From the Madisound BBS, a few years ago. 

I have a somewhat different take on your question about acoustic suspension speakers than others that have replied so far, FWIW. I believe that most sophisticated designers are finally aware of the situations where acoustic suspension speakers would make the best choice, and where a different approach might be preferrable. Efficiency seems to have dropped off the average customer’s radar screen. Power is now so cheap, and the ultimate difference in max SPL between AS and vented is small enough, so that I don’t think this is a major issue these days. I can’t back that up with hard data, but it is common industry wisdom. Also, it is not as simple as using any woofer that happens to work in a sealed box. If the mechanical suspension is contributing most of the spring force, it isn’t AS. It’s more like an infinite baffle. To get all the characteristics of a proper AS design, the box compliance must dominate. How important this is depends on how good your mechanical suspension is, and how linear your motor is. (I’m not debating the merits, just clarifying the terminology.)

The problem is that manufacturing a proper acoustic suspension woofer is a real pain. Few driver companies are anxious to put them in their standard line. In turn, this means that a designer/brand wishing to make an acoustic suspension speaker has to devote extra effort towards engineering a full-custom driver, and paying the premium that this entails.

To summarize a complex issue, the high compliance of acoustic suspension woofers make them ill-suited to automated production. It’s difficult to handle very soft parts, keep surrounds in shape as you glue them, maintain positions exactly as the glue dries, etc. Also, on a production line, its not easy to rapidly test an Fs below 20 Hz. Data acquisition time and ambient vibrations are both the culprits here.

(After I chose to design the 1259 woofer for the NHT 3.3 as an acoustic suspension, it took a great deal of arm-twisting to get any of our suppliers to even quote on a driver with an Fs below 25 Hz. The lack of AS woofer availability was one reason I decided to make the 1259 available to DIY.)

There’s one more factor that I personally think inclines speaker designers away from AS. Let me try to explain:

With an AS design, there is only one, and only one, box that will lead to the target response. There is no way to tweak the response of the system to "tune" things after the fact. (Besides active EQ, and a very small effect from stuffing.) If the production driver does not match the prototype, or if the designer wants to fuss with the results at the last minute… too bad. This means that AS design is less forgiving of error or uncertainty. On the other hand, many designers like to tweak the bass response with port tuning, long after the drivers have been placed on order. Given a typical woofer production lead time of several months, this can be significant.

Sorry if this was too much information….


Re: Cording

Another Editorial from a few years ago.
High fidelity recording….  frankly, its a bigger can of worms than just about anyone wants to think about.  
Audiophiles take it for granted that because we have only two ears, two signal channels must theoretically be able to reproduce exactly what we hear, provided the channels are applied correctly.  Unfortunately, the two-ear/two-channel logic is false, and only occasionally leads to really good listening experiences.  The problem arises because human ears are not just fixed points in space, to be simply fed from fixed microphones.  Rather, human hearing works in a complex way, with the ears and head cooperating to understand the timbre and direction of impinging sounds.  In other words, our ears process the local sound fields near to them, not just fixed points; they are moving, intelligent, directional sensors.  These varying local fields must be recreated as functions of time in order to properly convince the hearing system of a virtual reality. 
In one very reasonable analysis, recording/playback is essentially a spatial-sampling problem.  For reliable reproduction, many sample locations (channels) are required in a given room.  Further, if one samples the recording room at an inter-microphone distance greater than twice the spatial Nyquist, as defined by the shortest acoustic waves one needs to reproduce, one gets stuck with spatial aliasing during playback.  (Not frequency aliasing, spatial aliasing… the existence of spurious artifacts in the geometry of the reproduced sound field.)  This is neither negligible nor trivial.  In fact, some of us believe it is an important underlying reason why recordings tend to sound non-live, and just don’t get much better as one tweaks the tonal spectrum, increases the dynamic range or lowers the distortion beyond reasonable levels of accuracy.  Add to this spatial aliasing problem the differing boundary conditions between recording and playback environments, and true “fidelity” becomes an extremely illusive goal. 
It’s not just difficult to achieve true fidelity, it is almost impossible to properly define it.  The anachronistic notion of a perfect microphone connected to a perfect speaker is quaint, it is easy to understand, but it is essentially flawed.  In reality, there is no perfect one-to-one mapping between a sound field and any finite number of V(t) electrical signals.  This renders all recordings spatially ambiguous. Transfer-function-like descriptions of recorded fidelity, (eg- “frequency response”), are non-operative when mathematically irreversible changes of signal dimensionality are involved, ie- when one or more microphones are used.  Microphones collapse four dimensions of information, [P(x,y,z,t)], into two dimensions of signal, v(t).  Transfer functions, of course, can be correctly applied to amps and CD players, and such, only because the mathematical dimensionality of the signal is not changed.  The 2-D signal remains a 2-D signal.  When ears, loudspeakers or microphones come onto the scene, one is forced to employ non-transform metrics of recorded quality.  I realize this flies in the face of some very entrenched ideas, but: the frequency response of a speaker is undefined!
It is possible to pick some arbitrary functions to map between the recording and playback space, while ignoring the inherently under-deterministic nature of these functions.  For example, the average power spectrum with such and such time constants, or an anechoic impulse response at one meter, can be optimized by design engineers, and we all call it a day.  The audio industry, of course, then argues ad infinitum about which of these functions (if any) bests fits the human cognitive process, ignoring how profoundly reductionistic they all are.  This is essentially the situation we have in the audio industry today.  In fact, it is the best of what we have today.  Unfortunately, many in the industry, and many of the industry’s consumers, don’t understand what a profound and inadequate compromise such “specifications” as frequency response or distortion really are, when it comes to capturing and perceiving acoustic events.  It is certainly better for all that objective specifications do exist and are used.  The flip side is that specifications become a tool of stagnation, even in the hands of the well-intentioned. 
So where to go next?  I have in the past called recording “lossy compression.”  We take an informationally complex signal, we ignore aspects of it believed to be non-essential, and we encode the remaining data.  That is exactly what happens in the recording process, regardless of the number of bits, channels or sample rate involved.  Compression starts at the microphone.  Even if the recording medium itself has perfect electrical fidelity, it can at best preserve only that fraction of the information that the microphones send to it.  OK, reductionism is always necessary in life, and it can be done in sensible ways.  The trick is to toss the right data based on an understanding of the perceptual system, instead of the current trial and error machinations that comprise “mic placement” and “speaker positioning.”   There are a few people thinking this way, working on acoustic “wavefield synthesis” and “auralization.”  Good stuff.  But far, far from the kind of record/playback schema that are presently entrenched.   
[2014SEP30:  Edited for minor corrections.]


Thanks for visiting

I think it is safe to assume that the majority of people visiting this site know of me from my association with the audio business.  This career spans more than 35 years, and includes research, product design, writing and management, as well as the founding of several consumer brands.  My particular expertise falls under the heading of, “Loudspeakers and Acoustics,” although I have worked in almost all facets of modern audio technology.

However, there is another side to my life that I take very seriously. That is my creative work in music, writing and the visual arts.  Although I cannot claim to be a professional artist or musician, my work has been included in a number of exhibitions, festivals and publications worldwide over the years.  My Master’s degree from the MIT Center for Advanced Visual Studies is in, “Arts and Media Technology,” and I had a Post-Grad Fellowship there.  It remains interesting to me to study the intersection synergies between newly emerging arts and the technological landscape that exists and is evolving around them.

This site is very much a work in progress, with far to go.  My main intent is to share a sampling of my music and art, along with mementos of my career and personal life.  I plan to include some of my undeveloped ideas, silly sketches and midnight thoughts.  I certainly don’t expect that most of it will be of interest to many readers.  Still, these glimpses give a more honest and complete picture of my life and my personality, for what that is worth.

I hope that every reader can find at least one small thing that is useful or amusing within…. hidden amongst the mundane, the opinions and achievements, among failures and contradictions, regrettable decisions and insomniac reveries.  Oh, and thanks for having a look! I really couldn’t ask for more.





NOTE: Since the discontinuance of, there are a number of document links here that are now dead. I’m working on restoring an equivalent library within WordPress.