[denverdoc]

But the speed of sound does not change appreciably with humidity--ie less than one percent between 0 and 100 percent RH! The Sabin coefficent goes up generally with humidity but there are some frequency dependent differences--see previous link on earlier post. in general appears as if more efficient conversion of sound to heat, but most of all what is curious is that Telarcs recs would seem to fly in the face of what the other audio engineer's perception was--that high humidity was a wet blanket on the sound so to speak.
J

[Roc]

The folks at Telarc were quite sure about the effects of humidity on recording quality.
If you want more information regarding their observations I'd recommend emailing them directly.  They always write back.  
Write to producer Erica Brenner:  "erica@telarc.com"

[denverdoc]

Thanks for the contact. Initially as a joke I suggested an ultrasonic humidifier/ humidistat as the ultimate room acoustics tweak, but who knows, maybe there is some real utility there. One of the nice features of the DEQX preamp, is that it has a 100 presets of 3 band eq settings for that really nasty recording, etc. One obvious application not mentioned by the manufacturers is setting up Fletcher-Munson compensation the right way. Seems like there might be cause for devoting a couple presets for extremes in humidity as well.

Once i get my LA diy speaker system completed, I'll take some measurements at several humidity points and post them here to see what kind of measureable differences might be present as fx of RH.

[Roc]

denverdoc,

The subject of sound quality v/s humidity is mentioned in "The abosolute sound" magazine, issue #152, Feb/march 2005. Check out page #109.

TAS was questioning Telarc  owner Rober Woods as to why the sound quality of one movement was substantially different than that of a second movement on the same SACD.  Robert's reply was that they were recorded 1 month apart and the humidity was different/the culpret.

TAS had this to add:
"Do not laugh:  Anyone who keeps track of listening or recording sessions can tell you that higher humidity produces a more "liquid" sound."

As I said earlier I notice the oposite in my listening room.  Lower humidity is slightly better sounding than high.  But this could be equipment related.

I can say for sure that the room temperature makes a huge difference in how my VMPS ribbon monitors sound.  When the room/speakers are cold the speakers sound like tin cans in comparison to being toasty warm, even if the stereo is fully warm in both instances.  I keep my system powered up at all times.  After coming home from a trip I turn the house thermostat back up,  but won't attempt to listening for at least half of a day.  

Just thought I'd mention that.

Dave

[denverdoc]

Its bad when one  can't understand his own links--Telarc boys are right that with lower RH of about 20%, there is more rapid high frequency attenuation as a function of distance, but unless ones living room is really big, effect should be small. I'm still gonna try to take some measurements.
John