Relative air humidity on electrostat performance


Hello good people -

I sincerely doubt that I am the only person who has experienced this personality trait of electrostat speakers, that is, as the relative air humidity of the listening room increases/decreases through natural atmospheric changes the sound coming out of the speakers changes as well. In particular, as the humidity increases the sound becomes muddy, distant and diffuse - and takes more gain to reproduce a constant listenable level - and as it (the humidity) decreases the bass becomes much less noticable and the mids and highs are articulated to very high, and sometimes piercing, levels.

Now, I am a rather level-headed fellow and I do not let the above mentioned topic cause me to lose sleep. But what, if anything, outside of running a noisy dehumidifier either during or just before listening sessions can aid me in this dilemma? I mean, Lucinda Williams or Diana Krall deserve to be reproduced at the levels they are accorded to on a fairly consistant basis.

My system:
Krell 300 KAV
Blue Circle BC3(Despina) w/XLR inputs/outputs
Bryston 4BST
ML SL3'S
Transparent Audio Balanced Musiclink Plus (all around)

Thanks ahead of time,

Mark.
gpsguy
Mark,

Call Roger Sanders at Innersound. He is the absolute "authority" on this subject and I am sure would be happy to help. Good luck.

Gary
Maybe you should consult Martin-Logan since they designed the thing, if you really think its a problem.
Gpsguy -

Your observations are absolutely correct.

At least one practical solution is a variable bias voltage power supply. That's a feature of Sound Lab electrostats, and down here in New Orleans it comes in handy.

In high humidity conditions, full performance is easily restored by cranking the bias up a bit. If the humidity drops, then just crank the bias down a bit.

There's a pair of Sound Lab Dynastats for sale here on Audiogon right now, for a grand. They are quite competitive with the SL-3's. I'd be glad to tell you more about 'em if you'd like.

I don't know if it's feasible to retrofit a variable-bias power supply to the SL-3's. The only other solution I can think of is to go with the dehumidifier.
FWIW, I don't think Krell or Bryston is a good match for Martin Logans as they both lean toward the "bright" side. You might want to get some tube stuff.
I have my ML monoliths with a biased power supply to adjust the kV on the panels. It works very well. I initially did it because the older monoliths ran at a higher kV than needed--it just shortened the life and made them a bit on the bright side--particuarly once I got rid of the old grill cloth--something the newer ones do not have (and shouldn't). As a result, though, I learned I could actually tune the speakers to compensate for the humidity changes. There is no question--that ESLs are humidity sensitive. Now all you need is one that has a humidistat coupled to a potentiometer and calibrate it for best results in your environment (hmmm).