Today's audio secret originates with George Cardas of Cardas Audio cable fame, a man known to not only be intensely curious about all things audio, but also uniquely predisposed to come up with unusual solutions. His tip passed to me by way of Jim Smith of Avantgarde-USA who's presently working on a much larger version of his "31 Secrets to Better Sound". I just learned that the revised for-sale compendium could grow to more than 90 detailed tips, on how to maximize system performance at little or no cost to the pocket book, adverse effects limited to preconceived notions and undue experimental reluctance only. George's tip -- cunningly dubbed Mister Mastery by Smith for the time being -- would likely be the kind of first wacky, then strangely logical entry one might expect to find in his new 99 Secrets (or whatever the final count shall turn out to be).


Most audiophiles are unhappily familiar with the fact that their systems can morph from magical to mediocre in the course of a single day. Much has rightfully been made of the vagaries of AC power. However, once devices like the Running Springs Audio Haley stabilize line voltage at a steady 123V; once complete regeneration approaches like PS Audio and Exact Power guarantee a virtual disconnect from power line fluctuations; once various capacitive, inductive or other AC filters minimize incoming and self-generated noise pollution: What other variables remain at play if our systems should still undergo unexpected nose dives and magical recoveries, as though afflicted by bipolar syndrome?


Discarding psychological factors like fatigue or mood-induced perceptional shifts, what other variables constantly impose themselves on our audio systems? The qualities of the air! After all, air acts as the transmission medium for sound. Factors like altitude, barometric pressure, temperature and moisture content impact how and how fast sound propagates through the ethers. Altitude is naturally fixed unless you moved. In fact, your system's likely already voiced around how your particular elevation affects your median air density. However, temperature and moisture content can be controlled.
Jim Smith's Mister Mastery involves a water bottle terminated with the kind of pump-action mister head you'd find in the plant department at WalMart's [image shows battery-powered deluxe version - click for website]. 10 minutes before you intend to listen seriously, spray your sound room liberally with water mist to increase air density and reverse excessive dryness. Then hit play and see what happens. Cost of experiment? A few dollars. First observations in my home are very promising indeed. I should add that I live more than 7500 feet above sea level in a very warm, extremely dry climate. My results would likely be different if I still hung in Encinitas/California, within a foot walk from the beach and surf scene.


I intend to report in more detail at a later time when a prospective humidifier purchase has added further data as to the audible effects of higher water content in the air. A humidifier would introduce a more constant, deliberately controlled 'acoustical micro climate'. My questions right now revolve around how wetter, denser, heavier air will impact sonics; whether there seems to be an ideal range of moisture; and whether fixing this one variable (the other being temperature) undermines some of the strange roller coaster behavior of my system, simply by introducing a new constant and minimizing the factors that fluctuate.
battery-operated 'deluxe' mister, click to purchase
I'd love to hear from readers who've already investigated this issue or feel compelled to now. Should you write in, make a note of your home's approximate elevation; the kind of averaged climatic conditions during your test; how adding water content to the air altered the sound of your system; and, if possible, whether you could discern effects of "too much" or "too little". With your help, perhaps we can collect enough input to propose a few rough guidelines about what to expect. Incidentally, while seemingly wacky, I did check with a bona fide EE involved in audio manufacture. Propagation velocity of sound is definitely affected by the factors mentioned. This clearly is a viable subject of research that barely will cost a thing and might -- if early reports and first personal experiences are any indicators -- have surprisingly promising rewards. Want to share your thoughts or findings? Click here to auto-launch comments.


PS: Without denying the usefulness of our experiment, reader Roger Pinson corrects our assumption that increased moisture content increases air density. Corresponding changes in sound must now be associated with lowered density - or the sheer presence of more water molecules. Or something else (see second comment below). Writes Roger:

"While I was reading your tip regarding the effects of humidifying air to increase its density, some long-unused and near dead neurons from my past days of flying began to fire. I seemed to recall that as counter-intuitive as it seems, increasing humidity actually decreases air density. A quick visit to a density altitude calculator on the web confirmed this. Dew point is the variable, increasing it corresponds to increased humidity. The density altitude calculated shows the effects of increasing dew point (humidity) as an increase in density altitude ( lower air density)."

Our compliments to Roger. As seems common in audio, making observations about audible changes is one thing, generating unassailable explanantions of what caused them how, quite another.


PPS: Reader Chuck Beaman's letter points out how intricate this subject turns out to be, and how scientific data are available through the pro-audio community. Our sincere thanks for this collaborative spirit of "audiophile community in action". Hats off to Mr. Beaman. He writes:

Hi: This area of acoustics already has decades of prior study. The group interested in it? Pro sound reinforcement. Air dissipates sound energy in a nearly linear frequency line, sloping down as frequency increases. As relative humidity increases, the dissipation of sound energy also increases, again in a very straight line and increasing as the frequency rises. As the distance from a sound source increases, sound attenuation increases with frequency and in a geometric slope.

Example: A 10kHz note will be down -9dB at 100 ft, and down -45dB at 500 feet. Note: The above obviously is of interest to outdoor (free field) sound reinforcement. The distances involved in a home listening room are miniscule. The velocity of sound in air increases as temperature rises. Air density decreases as temp rises. Altitude has very little effect on the velocity of sound, for a given temp.

Refraction of sound occurs as sound passes through different temp strata. That's why on a cold, sunny day, you can hear tiny sounds at a great distance. And that's why at an outdoor concert with a breeze or wind blowing, the sound from the stage appears to vary in loudness. The common assumption is that the wind is "blowing the sound around." That is false, since the sound is moving at 770 MPH (@ sea level, 72.5F) and even a stiff wind has no effect on the sound. The changing temp layers -- ground temp vs. air temps -- cause the sound to bend up or down.

You either inadvertently or intentionally didn't mention what "effect" that misting the air resulted in. This is a good thing, and encourages experimentation. My guess is that what is being done by air misting is reducing the temp differential from top to bottom in the room. This may result in a more even dispersion of the sound source, since normally, the sound in the upper, hotter part of the room is traveling faster than in the lower, cooler part of the room; again, refraction.

This intrigues me as to what effect a ceiling fan in a listening room would have. Run it for 10 minutes before a listening session to "blend" the air. Even try running it at slowest speed while listening. Have it "pull up" during the summer, and "blow down" during the winter. As for me, I always have windows and doors cracked open, so I usually have a good blend ontemperate days.

Source: "Sound System Engineering, 2nd ed. Don & Carolyn Davis 1987, 650pgs. Howard Sams Co. (The authors are owners of Syn-Aud-Con.) They also refer to the following, which may be worth digging up: Journal of the Acoustical Society of America, June 1997 "Review of Noise Propagation In the Atmosphere."