Audio

The Audio Envelope

B-W-sound-waves

We generally end up picking our own poisons.

A recent (and rather spirited) debate in an online audio expert group awakened me as to how complacent our industry has become regarding performance quality and the almost automatic acceptance of our own limitations. Sadly, only a handful of the 4000 members actually participated.

For all the billions of dollars spent on audio, has any research lab, commercial entity or private individual really run the table creating a system that can actually perform to the limits of human listening extremes?

Ignore for a moment our traditional definitions of sound. Let’s throw in the entire gamut of vibration and sensory experience, from gut-wrenching infrasound to EKG igniting ultrasound, from the quietest experience of vanishingly low noise levels to loudness levels inducing pain. A system with an impulse response bordering on the fantastic where any part of the audio envelope can be accurately analyzed in its entirety. An entirely integrated system where time, energy and frequency are all reproduced as accurately as possible given existing technology and materials.

Many of the piece parts exist, but I’m fairly sure they’ve never been put together in one place at any one time. Now there is this guy in Wisconsin who converted his kitchen into a subwoofer enclosure…but I stray.

  • The Analysis: Why not start in the middle of the audio reproduction transfer function with loudspeakers as we so often do? Has there ever been a loudspeaker system with near DC to ultra-high frequencies built with near perfect amplitude, phase, impedance and impulse response able to reproduce 140dB?
    Do we have a recording and playback system capable of the same? The “state of the state” is certainly better than on the transducer front, but existing systems clearly don’t hit the envelope limits defined as the human dynamic range of hearing and feeling.
    Amplification? That’s what we do best, although amplifiers’ complex relationship with loudspeaker limitations continues to mock amplifier designers with regularity.
    Signal processing? Really an effort still in its infancy. It will be fun to see where upcoming generations of engineers will drive the field. Sorting out loudspeaker and room acoustic performance limitations should keep them busy for some time.
    Acoustic systems? Perhaps the only meaningful thing I’ve ascertained from ETC measurements is that no meaningful reflections sound awful and over five reflections do, too, unless you’re going for the “Voice of the Almighty” effect. Clearly an area with much work to be done and we eventually will have to learn to play nice with owners and architects in order to truly sort it out.
  • The Compromises (Good Enough or Best Possible): Next will come the inevitable discussion about compromises. Goodness knows that’s what we do best, and audio engineers have developed the annoying habit of thinking they know best based on some statistically averaged conclusion ascertained some generations back. Many of them are based on the “50% can’t tell so it’s invalid” criteria, as opposed to the “what about that one guy in the back who’s correct 100% of the time” standard.
    We don’t even go back and check the fundamentals commonly accepted as dogma. Questions arise regarding the number and prioritization of these compromises, and that’s at the core of many spirited discussions.
    Because we don’t have that “Audio Envelope” capable system and little idea of how to accurately quantify one individual’s listening acuity versus another, we generally end up picking our own poisons. Some listeners want horns in their home so they can get that dynamic range. Some want exotic materials to get the best transient performance on their violins. Some want big thumps way down low. Many are perfectly happy with near-telephone quality audio (earbuds come to mind).
    I suspect it really boils down to what emotionally moves an individual most effectively, undoubtedly driving a plethora of differing opinion. The flaws inherent in our compromised systems stir the debate, and it would be enlightening to explore why my compromises are better than yours, or vice versa.
  •  Conflict Between Audiologists, Artists, Audio Engineers and Audiophiles: You’d think the goals for all four groups should be the same. Suffice to say, they often coincide less than one might hope, and there’s less communication between these groups than would seem prudent, given the similarity of purpose.
    How many in the audio community commonly attend the AudiologyNOW, NAMM, AES, Acoustical Society, CES and InfoComm conferences? I wouldn’t be too surprised if there were more hot dog vendors than industry veterans who attend the lot. Each group represents a portion of the whole, yet coordination between the various groups is tenuous at best. Perhaps a generally accepted scientific criteria for audio acuity along the lines of 20/20 vision might be a good place to start. What exactly are the criteria for “golden ears” as opposed to “tin ears,” anyway?
    There must be a few unique individuals who transcend the individual groups to better understand the communal needs and expectations. If nothing else, it would be good to use common language and terminology some day in the future.
  • The Practical Versus the Possible: Our world of cantankerous curmudgeons hardly seems like the ideal gene pool for determining where and on what the next generation of teenagers will be spending their parents’ expendable income, but there it is. Yes, we have our standards, and most are very good, indeed—but perhaps not always pushing the edges of the audio envelope. How well do they hold up with the improvements in processing, data transmission and storage capacity of recent vintage? And exactly how do we prioritize industry efforts to make it better?
    Time will tell.

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