By Roger Skoff
Some years ago, I and two friends (whose name shall be withheld to protect the innocent) were sitting around recovering from a Dim Sum lunch at “Seafood King”, our favorite Cantonese restaurant, when somehow the conversation turned to the subject of the “perfect” loudspeaker.
We were all in the industry at the time – one of my friends being a manufacturer of specialty speakers, and the other the U.S. head of a well-respected Japanese Hi-Fi electronics and transducer firm – so for us to wind-up on a topic like that wasn’t really all that surprising.
Although we were all a little logy from a more than abundant meal and perhaps even a little lightheaded from an equal abundance of Tsingtao beer, we tried as well as we could to approach the matter of the perfect speaker seriously. “What are the greatest shortcomings of conventional speakers?” we asked ourselves, and came up with a whole list of problems ranging all the way from limited frequency range, to the consequent need for multiple drivers, and hence a crossover network (Everybody knows that even the simplest crossovers cause problems and that fancy high-order ones can be death to good sound) “How about non-uniform dispersion patterns?”, one of us asked. “And how about diaphragm inertia causing problems of transient attack and decay?” chimed-in another. “What about “box” coloration from the enclosure?” “What about the need to have an enclosure at all?” And on, and on, and on…
We kept at it for a while, noodling furiously (All that thinking brought back our appetites, so we had ordered some Chow Mein and more beer). Finally, we had what we thought was a full “wish list” for the perfect speaker system: It would have to have absolutely “flat” frequency response, from DC to far above the dog (or even bat) range. It would have to be omnidirectional at all frequencies. (Anything else would mean that its frequency response off-axis would be something other than flat). For proper reproduction of the full dynamic range of anything a listener might wish to hear, it would have to be capable of playing both very quietly and VERY LOUD with equal ease. To even approach perfect transient response, it would have to have near instantaneous “rise” and “fall” times. To eliminate colorations caused by the storage of energy in its enclosure, it would have to have no enclosure at all. And, finally, to eliminate (or at least reduce as much as possible) all remaining sources of distortion or sonic coloration, it would have to be non-mechanical, non-magnetic, and have effectively zero mass.
It’s amazing the insights you can come up with while eating Chinese food. No wonder they invented all that stuff: gunpowder, paper, the compass – even pasta!
So anyway, there we were, noodling the perfect speaker. We’d come up with WHAT it had to do; now we had to figure out HOW to do it, and, after more Tsingtao, we had a breakthrough! We would follow in the tradition of the Ionovac, the Hill Plasmatronic, Nelson Pass’ corona-discharge speakers and other such devices, except that we were going to do it RIGHT – instead of just plasma or ionization effects, we would use two gigawatt X-ray lasers – one for each stereo channel!
Why that much power, you might ask. Well, what we intended to do would NEED lots of power, AND, we wanted to have plenty left in reserve, regardless of any dynamic peak we might have to contend with. And why X-ray? Well, we were going to use a LOT of laser energy, and if it were visible, it might blow the mood at those times when we just wanted to turn down the lights and get into the music!
Everybody knows that what we perceive as sound is nothing other than a series of pressure waves in the atmosphere, alternating in frequency and intensity (amplitude). We normally think of those waves as repeatedly varying from positive to negative and back, but the reality is that sound doesn’t have to be positive to negative; it can be positive to more or less positive or negative to more or less negative. It’s not the positive or negative pressure that we hear, but the CHANGE in pressure and its rate and amplitude. This can easily be seen by microscopic examination of an LP groove or simply by looking at a multi-frequency, multi-amplitude oscilloscope trace, and it was how our speaker would make its sound:
Using our constant-beam gigawatt lasers to actually destroy molecules of air, we would create tiny areas (the points where the beams impinged on and obliterated the air) of lessened air pressure or even – if the beam were intense enough – total vacuum. By modulating the intensity of the beam with an audio input signal, set-up to act much in the same manner as the grid of a vacuum tube, we could produce, at the point where the beam and the air meet (a TRUE point source) instantly and continuously variable negative pressure waves of amplitudes anywhere from ambient pressure to total vacuum!
Voila; a true zero mass, infinite frequency range (constrained only by the heat-transfer coefficient of the air molecules), absolutely flat frequency-response, inertia-free, totally omnidirectional, zero distortion, crossover-less, enclosure-less audio transducer. Exactly as we had set out to create, it was The All-Time Absolute Ultimate World’s Greatest Speaker System!
Of course, there were certain small drawbacks to our plan: For one thing, the speakers would draw VASTLY more power than even the greediest Class A amplifiers, so you would definitely want to turn them off when not in use. For another, the lasers would likely be both large and expensive, notwithstanding their power requirement, so there could be certain budgetary and room-size constraints. And, not to be forgotten, was the fact that if you played them for too long at any one time, they could, by destroying all of the air in your room, cause you and any others who might be listening with you to die of asphyxiation.
That last issue could easily have been solved by simply keeping a window open as you enjoyed your music, but there was another problem that might have been worse: Ionizing radiation. As the lasers destroyed air molecules, vast amounts of gamma rays (the same sort of high-energy radiation as released by an atomic bomb blast) would have been emitted which, if the listener were not suitably protected, could have resulted in radiation sickness and a slow, lingering death. (In some ways, NOT opening a window might actually have been better – at least it would have been quicker and, presumably, less painful)
With more beer (but no more noodles), we found a solution that would easily and effectively eliminate both possible hazards: All the listener would have to do, whenever the system was in operation, was to wear an air-tight, lead-lined, full-body radiation suit with a built-in SCUBA-style air supply (With that last feature, the listener could leave the window closed, so as to not bother the neighbors with excessively loud music, and still be able to breathe easily for as long as the tanks held up)
As is so often the case, though, solving those problems just led to another one: When the listener was in his suit, he would certainly have been safe and he would certainly have been able to breathe; but because the suit was air-tight, and because sound is pressure waves in the air, he might not have been able to hear the music!
Given three such solid professionals as ourselves, however, even a surfeit of Chinese beer and goodies could not dim the sum of our wit, and we found a solution to that last problem with relative ease: All the listener would have to do would be to wear a Walkman (or, currently, an ipod or such like) under his suit and, after carefully synchronizing what it was playing with the music being played on the main system, listen to it with earphones!
We’re not taking orders yet, but we might. Are you interested?