Does humidity affect tone?

[FoxHound4690]

Hey guys,
I was hoping you guys might be able to shed some light on this for me being as there's many, many people on here that are far more experienced and knowledgeable than I am...

Does relative humidity have an affect on the way an acoustic guitar can potentially sound?

Like on a stifling hot day when the humidity is through the roof... is the tone more dull than what it is when you, say, are playing in a nice cool air conditioned room for example?

It's something i'm curious about because a lot of luthiers and people in general seem to believe this theory.

[fazool]

Yes absolutely.

My fingerstyle guitar sounds like its stuffed with wet socks once the humidity gets above 45%

[Wellington]

Yep, definitely true for my LL16 anyway, it’s much duller and muffled sounding when it’s really humid, like 70%, luckily that’s not the average humidity level but it gets there.

[llew]

For sure. My guitars seem to love around 45% RH.

[SprintBob]

Unless you have a carbon fiber guitar which sounds the same at 25% RH as it does at 70% RH. They are worth a look to have one in the stable for that reason IMO. Love my Rainsong.

[jim1960]

When a guitar soaks up too much, it sounds like someone threw a wet blanket over it. The attack of the notes suffers.

[guitar george]

Everything you need to know about the subject of guitars and humidity is covered in this "Care and Maintenance" guide by Larrivee Guitars.

https://www.larrivee.com/pdfs/Larriv...aintenance.pdf

[Guitarplayer_PR]

Originally Posted by FoxHound4690

Hey guys,
I was hoping you guys might be able to shed some light on this for me being as there's many, many people on here that are far more experienced and knowledgeable than I am...

Does relative humidity have an affect on the way an acoustic guitar can potentially sound?

Like on a stifling hot day when the humidity is through the roof... is the tone more dull than what it is when you, say, are playing in a nice cool air conditioned room for example?

It's something i'm curious about because a lot of luthiers and people in general seem to believe this theory.

Absolutely. On acoustics, minor changes can make. . . great changes.

[HodgdonExtreme]

Clearly, as the responses indicate, the answer is yes.

I can literally assess the humidity of my guitar by how awesome it sounds and projects.

When it starts sounding insanely good, I start worrying because I know humidity has fallen to below 40%. It sounds muffled and stifled above 50-55%.

[gmel555]

Originally Posted by fazool

Yes absolutely.

My fingerstyle guitar sounds like its stuffed with wet socks once the humidity gets above 45%

I've noticed this as well(fingerpicking and flat picking). Some guitars more than others. Somewhere between 45-50% there's a loss.

[Alan Carruth]

A lot of the 'tone' of the guitar comes from the way the resonances that are built into it interact. This produces peaks and dips in the spectrum that enhance or cut down on the sound at particular frequencies. When there are two that are close together in frequency they can 'talk back' to each other, and small changes in the relationship can make a big change in the sound.

Water vapor is a little less dense than nitrogen or oxygen gas, so air with high humidity has a slightly higher speed of sound. This alters the pitch of 'air' resonances, such a the 'main air' or 'rum jug' resonance, usually displacing them upward in pitch a little bit.

Wood absorbs moisture from the air or gives it off as the relative humidity changes. As the R.H. rises the wood gets a bit denser and also somewhat less stiff. Any 'wood' resonance, such as the 'main top' tap tone, will tend to fall in pitch as the humidity changes.

With the 'wood' resonant modes falling in pitch, and the 'air' modes rising with rising humidity, the relationships can change. In some cases it doesn't take much of a change to alter the tone of the guitar. You can check this out by simply adding a few grams of weight by sticking on a wad of poster adhesive somewhere on the top. This will drop the pitch of any resonance that is active at that spot by a bit. It can be surprising how even a small change in some places can alter the tone. Blocking part of the sound hole with a card changes the 'air' pitches (and particularly the 'main air') and can also change the sound.


I believe that the 'damping' of the wood, the rate at which it dissipates energy as it vibrates, rises as the humidity goes up well. It's in the nature of damping that it tends to 'eat' high frequencies faster than lows. This would account for some of the lack of 'sparkle' or 'edge' when the humidity is high.

Makers tend to adjust things to get the instrument to work as well as they can when they string it up. Instruments that are made when the humidity is high might sound better in summer than winter for most of us. These days most makers I know of try to control the R.H. to below 50%; on the low side of 'comfortable', which tends to give decent sound and also avoid cracking problems when things get really dry.

[blacknblues]

All of my guitars sound better in the winter when they are dry. I keep my guitars humidity levels in the mid 30s during winter and they sound great! Summer is always a challenge because it is harder to lower humidity levels to my preference than it is in the winter....and yes I know the risks but I am willing take them.

[slide496]

True for mine whether acoustic or electric, more so in dry weather. In my NYC coop the humidity can get below 20% and they all sound alarmingly dead and lifeless - I use a humidifier and try to keep them at 30% They do much better in the spring and summer when the heating system is down, but need strings changed more often

[Dru Edwards]

Like others have mentioned, humidity affects tone. I believe more so on all solid wood guitars as opposed to laminates.

Guitars have a humidity sweet spot, you just need to find it to bring out the best of the guitar.

[RalphH]

Yes, but how much depends on the guitar.

With my hummingbird which is all solid spruce and mahogany, I can hear a difference in a few of % RH. I like it best at 45% RH. By 48% it sounds different to me.

With my GS mini which is made of Koa (a more humidity stable wood aparently), and with its laminate back and sides I hear very much less difference. Even 15% RH difference seems to have little affect on the tone. Anything from 45-55% and i can't hear a any difference at all.