How quickly can a sudden change in humidity levels affect a guitar?

[dgb]

Today I was playing my rosewood guitar in an air conditioned room (not a particularly good room for acoustic sound) and the guitar sounded really full and pleasant. After finishing up I took my guitar through to the porch where the door was wide open and left it sitting on a stand.

When I picked it up a 1/2 later, it sounded thin and lifeless.

Humidity levels were about 96% here today.

I realise a sudden drop or rise in temperature can instantly affect tuning, but is it the same for sudden humidity change? (or are my ears playing tricks on me?)

D

[gmm55]

But what you describe in fact seems to be temperature related. You went from an air conditioned room to a porch with access to the outside air, which I surmise must have been warm for you to have had the air conditioning on in the first place.

My own conjecture, based on casual observations, is that very significant humidity changes can become apparent in instruments in a few days, for temperature perhaps as little as ten or fifteen minutes. Tempurature can certainly affect tone. But of course changes in humidity often necessarily accompany changes in temperature, so it can be difficult to deterime what caused what. In your case, all you had to do was move the guitar back to the air conditioned room for 1/2 an hour. If it sounded good again, then you have your proof of temperature. Perhaps you can do that if it occurs again.

Your ears were not playing tricks on you, but the cause of the change in sound likely was.

[harmonics101]

I believe that humidity has more affect on sound than the actual guitar itself.

To change the guitars equilibrium would take much longer say 48 hours or however extreme the climate gets in your area.

That is why playing in the pacific northwest dry side is so satisfying. They all take a bit of a hit in the winter time but i consider myself blessed with perfect climate. Not withstanding any cracks due to humidity issues

<theory end>

Harmonics101

[taylorcc]

The space you are playing in has a big impact on the sound you hear when you play your guitar.

Take it into the bathroom (small room, hard surfaces) then try it in the living room (larger room, more sound-absorbing items such as upholstery, drapes, rugs etc). Does it sound the same in both rooms? Similarly for playing inside and outside.

[gmm55]

Originally Posted by harmonics101

To change the guitars equilibrium would take much longer say 48 hours or however extreme the climate gets in your area.

<theory end>

Harmonics101

To reach equilibrium yes, but changes do in fact occur within 48 hours, and significantly within 72, if the difference in humidity levels are also significant. I have watched 2mm open center seams on violins close up to almost nothing within three days of being moved into a humidor for anticipated repairs. I would also add that wood appears to take up moisture faster than it will give it up, but I am not sure why.

And the other replies beat me to my edit, as I was going to ask where the guitar was played in the second lifeless condition.

[dgb]

Originally Posted by taylorcc

The space you are playing in has a big impact on the sound you hear when you play your guitar.

Take it into the bathroom (small room, hard surfaces) then try it in the living room (larger room, more sound-absorbing items such as upholstery, drapes, rugs etc). Does it sound the same in both rooms? Similarly for playing inside and outside.

Strange thing was that I went back to the previous room with the guitar after and it still sounded thin and lifeless. The rich bass had all but vanished.

[patticake]

yesterday our apartment went from 44% humidity to 24% in a matter of an hour if even that long. my husband is building a guitar, and the top is braced and slightly dished. the entire top, bracing and all, not only went flat - it inverted a bit! and that's in a max of one hour's time. the only wood guitar that was out of its case was an all lam 3/4 and 2 rogues, so not sure how it affected fully built guitars - i didn't want to know enough to dry our all solid or even solid top guitars up.

btw, we have a better humidifier on the way!

[dgb]

Originally Posted by patticake

yesterday our apartment went from 44% humidity to 24% in a matter of an hour if even that long. my husband is building a guitar, and the top is braced and slightly dished. the entire top, bracing and all, not only went flat - it inverted a bit! and that's in a max of one hour's time. the only wood guitar that was out of its case was an all lam 3/4 and 2 rogues, so not sure how it affected fully built guitars - i didn't want to know enough to dry our all solid or even solid top guitars up.

btw, we have a better humidifier on the way!

That sounds pretty crazy. Amazing what the weather can do.
I didn't even believe humidity was an issue til I got my most recent guitar. My hogs don't seem to be affected by it though.

[harmonics101]

I definitely agree the relative humidity of where the guitar was built makes a HUGE difference with regards to stressing the guitar.

That is why (and i am sure it most likely is an incorrect belief) i feel more comfortable with my Gibsons going dry (since they are made in Bozeman a rather dry geographic area) than i am with my Martins !

Hope my amateur assumptions are incorrect but definitely, where the guitar is made can make a difference in the future.

<end humble opinion>

Harmonics101

[tadol]

Most guitars from larger builders are built in climate controlled areas that mimic what they consider to be the "average" humidity level of all the places that they expect to ship them to - I think that's about 55-60%.

I don't think its the back and sides that you see the quickest change from - I'd guess its the spruce and possibly the bracing that is resonding so quickly. I'd be pretty careful about moving guitars between those kinds of extremes in temperature and humidity. That's the kind of thing that can cause cracks in the top in very short order - depending on how heavily built and braced the guitar is, of course.

[Ed422]

I don't know if I still have it on another computer, but years ago I found a study on the rate of loss and gain of water in wood. In ambient conditions (i.e. Normal room conditions and temps), even wood 1/8" thick takes days to acclimate. Even in a steam tube, it takes hours to make a significant difference in water content.

Ed

[tadol]

Don't want to argue - but he went from an air-conditioned space ( assumed dry ) to hot exterior, very wet. You'll see a change pretty quickly -

Plus you have to worry about the finish, glue joints, and the tension the strings are placing on many of the components.

In a steam tube, you can change a strip of 1/8 wood from something that will crack if you look at it wrong, to something you can tie an overhand knot in , in alot less than an hour - usually about 15-20 minutes, actually -

http://www.finewoodworking.com/Skill...t.aspx?id=2962

Wood is amazing stuff - and quick, extreme changes in temperature and/or humidity can affect a good guitar very, very quickly - I'm just saying its cheaper to be careful.

[Ed422]

Originally Posted by tadol

Don't want to argue - but he went from an air-conditioned space ( assumed dry ) to hot exterior, very wet. You'll see a change pretty quickly -

.

Maybe condensation. The study I saw was for bare wood... with a guitar, remember one side is sealed.

I believe there is a perceived (and imagined) change but I don't believe (accurate) measurements with a hygrometer would show any in a half hour.

Ed

[briggleman]

Well here is my theory.

Air conditioned room, enclosed.
1) Air is dryer, however colder air is also denser. Sound travels faster in denser air.

2) As mentioned before, enclosed room. More surfaces to bounce off of, to absorb, to reflect.

3) Wound Steel strings E A D and sometimes the G, dryer air, less effect on the strings

Outside
1) Air is wetter, more humidity. Air is warmer, less dense. Sound travels slower.

2) No enclosure, less reflections of the sound, nothing is absorbing or reflecting the sounds back at you.

3) Wound Steel Strings would collect moisture and hold it, making them heavier, less vibration. Going back inside, it would take them awhile to lose that moisture.

All the above is conjecture.... just throwing out ideas. For a finished guitar, it would take more than a 1/2 hour for humidity to affect the guitars woods. Yes the inside would be affected immediately, but not to the point of affecting the sound.... again, my opinion.

[DenverSteve]

Originally Posted by taylorcc

The space you are playing in has a big impact on the sound you hear when you play your guitar.

I would agree that your change from an enclosed room to an open area was probably more the issue in that short of time than the change in temp/humidity.
I didn't see whether you took it back to the original room and checked it but it's no different than where you sit in relation to your amp. or PA. Off to one side the instrument/vocals will sound completely different than if the speaker is directly behind or in front of you pointed at you. Sit close to a solid wall and have the sound projected back at you or have someone else play the guitar for you so you can hear it from in front of it and I guess it will immediately sound better.

I see that you answered part of my question. I have noticed over the years that sometimes I pick up a guitar and marvel at its sound only to think a short
time later that the guitar didn't sound quite as good. I believe it's all in our heads. The instrument won't change in a very short period from external influences but how you think you hear, see or sense something in general will.