Humidity and its effect on loudspeakers

Loudspeakers
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Hi all, I have mentioned this in passing on other threads, but thought I would start a thread and see if anyone else is interested.

I have (like many here) a few pairs of speakers.
Mine are mostly 1990s, and one pair from 1970s.

They all, to some extent or another, change their sound dependent on the relative humidity (it might be proportional to absolute rather than relative but difficult to tell the difference).

Best sound seems to be at 45% RH or lower (though it rarely goes below 45 here and usually stays above 50%).

Mechanism seems obvious to me: the more paper and wood involved in the design, and the cheaper the wood and paper involved, the less stable it would probably be.

My ā€œbestā€ speakers are little affected and sound great pretty much all the time (very dense cabinets and all 3 drivers in it are non-paper).

The rest are
paper cone / fabric dome (affected noticeably)
paper cone / Mylarā„¢ dome (affected a bit)
(both the above with fairly decent MDF cabinets)

and finally my 1970s speakers - 3 drivers all paper (12, 8, and 4 inches respectively), and ā€œchipboardā€ cabinets from 1970.
Affected quite a bit, but less easy to tell at the top end given itā€™s a 4 inch paper cone tweeter.

Any thoughts?

And any comment from PSA (@Chris_Brunhaver ) on PSA speakers and testing - any tests done on humidity changes, in the industry more widely or PSA in particular.

It is possible I am alone in my thoughts on this, also possibly I have just invented a new line of ā€œaudiophileā€ humidifiers / dehumidifiers for folks to worry about :smiley:

(recall we donā€™t have air-con routinely in the UK and where it does exist (typically in office buildings and the like) it can be pretty awful - overly dry, laden with bacteria, low performance etc. etc.)

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One of my Magnaplanar pairsā€¦the wire on the ā€˜mylarā€™ sheet pulverized

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Ah yes I should imagine planar speakers might be sensitive to that, even if not paper or wood.

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Funny you should bring this topic online today. I was thinking how good my very inexpensive floor standing speakers sound at the moment. I checked and the RH is at 39%.

Speakers have an MDF cabinet with one 1" silk dome tweeter, a 6.5" mid/woofer (material unknown) and two 6.5" passive radiators identical to the active mid/woofer.

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Well, our planar speakers are made differently from Magnepan in that the ā€œvoice coilā€ traces on the diaphragm are made through a different process - a caustic photo etching process, similar to what is used for a flex circuit or circuit board. There is a photoresist coating put on the aluminum material that is protects it from being etched away that also seals it and prevents it from being oxidized or sensitive to salt and moisture. The only part that is exposed is where we solder to our terminals and this has a rubberized CA glue covering it and kapton tape and so they shouldnā€™t be very sensitive to humidity (though we havenā€™t seen any issues).

Hope this helps.

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ā€¦and I guess no paper cones these days, thanks for the answers all :slight_smile:

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image1100Ɨ1100 48.3 KB

I am currently utilizing the AC-PiFe (wood cone) in my Pure Audio Project Trio 15 Classics. Typically they offer paper cones.

Think Again:

Voxativ

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I suppose Wilson still uses paper cones in some bass drivers? I could be wrong though.

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My Sanders Sound Systems 'stats are somewhat sensitive to humidity. The panels output level reduces just a bit as humidity reaches 50% or more. I can compensate with the LMS by changing panel output levels. My ideal humidity level is also around 30% to 40% RH. Without adjustment to panel level the sound ā€œdarkensā€ as humidity rises.

In the summer months I just turn on the AC in the house to reach those ideal humidity levels.

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I have Martin Logan CLX speakers and on the ML forums I have read that high humidity is not ideal for electrostats performance or longevity. I have dehumidifier in my room/basement. I keep it no higher than 35-40%. 30-35% is the norm most of the year.

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The air density also increases with humidity. The ā€œthicknessā€ of the air as a transfer medium might have something to do with the sound transmission characteristics.

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Why is humid air lighter than dry air?.

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Relative humidity and temperature are usually highly correlated depending on the dry temperature (your thermometer reading) and the dew point. In my neck of the woods RH is typically high during the height of the summer and low during the winter months (despite the fact it might be snowing outside!). Which is why Iā€™ve never been able to unwind the two for correlation to my subjective impression of SQ. It is beyond question passive components, driver surrounds, spiders, the electro-mechanical components in the motor will have temperature coefficients. Not discounting the possibility what we observe (including me) really is due to RH, but have my doubts whether temperature or RH as real root cause of that change in SQ can be unwound. My remarks donā€™t apply to certain types of panel speakers where the problem is more basic -arcing. Thatā€™s an outright damage risk.

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I think I see the problem hereā€¦ you folks should move your speakers indoors

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Indeed, not easy.
Here in the UK of course we regularly get ā€œ4 seasons in one dayā€ and the RH can vary quite significantly despite little actual change in temperature, and it is still not easy, and of course involving subjective analysis.

I agree though itā€™s definitely making a differenceā€¦

ā€¦but I havenā€™t gone to the extreme of dehumidifying, partly because ventilation is more important to me (especially now airborne viruses can cause so very much medical mayhem) so doors and windows are often open wide, and almost always cracked open a bit.

Itā€™s all good fun :slight_smile:

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Dā€™oh!

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its always those small details thatā€™ll get ya

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Every time!
Your answer marked as the solution, of course :smiley:

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:laughing: its just how I do it here

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Move to Arizona John @joma0711 :slightly_smiling_face:

Cheersā€¦I owe you an emailā€¦been very busyā€¦also need @Dirkā€™s advice on an LP12 with Seperate power. Also owe him a long overdue email.

Stay dry Brother !

Joe

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