Recording your Acoustic guitar: What Absolute Humidity does your guita sound best at?

[keith.rogers]

Hmm. Well, this is veering a bit into the "too much navel-gazing" realm for me. So before I step into the grumpy old man deep end, my short, immediate thought is, "Just press the red button and get one with it!"

So, I mean, I do have hygrometers in my music room so if the RH is really low (happens a few times in the winter), I'll leave the "good" guitar in the case, but anything else is fair game. (I do have a room humidifier I can crank up if I do have to record something and it's out of range, but the "have to" part of my life is increasingly approaching minuscule .)

Yes, everything does matter, but only to a degree small enough that it takes a crapload of small things to really make a difference. I just cannot think of a time when this [AH/RH] would have been an issue in the final product. Every time I listen to some older recording, made with who knows what all going on, it's never the case that I think, "Oh, I wish I'd had this mic, or waited for the AH to change, etc." or some other thing that, in the end, is never what I'm hearing [wrong] in those recordings. Mostly, I'm just glad I captured something, or in many cases, some people or mix of people and place, that won't ever happen again.

[ChuckS]

As far as humidity goes, I think if it's much over 50% my guitars lose something in their tone (change in the top's velocity of sound?). I don't notice the tone being negatively affected with low humidity, and maybe actually sounding better as the humidity is lower, but I really don't want them exposed too long if it's below about 35-40%.

[KevWind]

Humm Interesting but I never really thought about it much, where I am it is mostly dry . We have a house ERV system, but one of the fan blower motors is out and right now it is 42 RH outside and 19 RH inside at 8000 ft. about 6 degrees outside and 70 inside

[TBman]

No effect. I don't check the wind speed either,

[AcousticDreams]

Originally Posted by b1j

I tend to think more about how wet or dry the guitar is than about the water content of the air.

Originally Posted by jim1960

That's correct. A guitar that's been sitting in 70% humidity for a month isn't going to sound better simply for having brought it into a room with 40% humidity. Wood takes on and releases moisture.

The Question at hand was:
How Absolute Humidly effects the sound through the air. It was never about how RH effects the guitar, and thus the sound of the guitar. It is about how does Absolute humidity effect the sound after it leaves the guitar. Hope that makes better sense. My fault in the way I explained it.

My house Guitar playing temperatures are probably much wider range than most. In order to save energy I have at least a 25 degree fluctuation range in my house during the course of a years time. I will only warm my house to house to say 62 to 64 degrees during winter time. And in Summer I might cool the house to 85 degrees.

And this is why I asked the question about Your house temperatures and RH. From those two you can derive the Absolute Humidity.

Regardless, good information revealed b1j & jim1960. Most importantly that if I keep my guitar humidified to the correct percentage, the guitar will itself with perform at that humidity. Probably all of us are Guitar safety conscious and keep our houses at the specified 40 to 55% RH levels.

The more relevant question I should have asked is:
What temperature do you keep your house at? I am assuming that most of us are RH very conscious, & probably keep your houses at more constant temperatures range than myself.

[The Watchman]

Understanding the difference between relative and absolute humidity, I think the question would be how would moisture in the air change the tone. Are certain frequencies enhanced, sped up or slowed down? Is it measurable? If so, how would that translate to actual sound quality? My guess is negligible.

[jim1960]

Originally Posted by AcousticDreams

The more relevant question I should have asked is:
What temperature do you keep your house at?

I keep my house at 72° in the winter and 70° in the summer. But honestly, I think you're off in the weeds on this. I don't see how a degree or even 10 is going to alter the sound of your guitar in any noticeable way so long as proper humidity is maintained. The change comes from the amount of water the wood is holding not the temperature in the room.

When you see those wood sellers and luthiers talk about their wood stores, you don't hear much at all about the temperature at which they keep their facilities; the number you will hear, though, is the humidity level they try to maintain.

[AcousticDreams]

Originally Posted by jim1960

I keep my house at 72° in the winter and 70° in the summer. But honestly, I think you're off in the weeds on this. I don't see how a degree or even 10 is going to alter the sound of your guitar in any noticeable way so long as proper humidity is maintained. The change comes from the amount of water the wood is holding not the temperature in the room.

This has nothing to do with the wood moisture, retention. This has to do with how sound reacts in the air with moisture particles. Complete different subject matters.

Absolute humidity and Relative Humidity are two completely different aspects. Relative humidity is about how much humidity the air will hold to a specific temperature. Absolute humidity is how much water is in the air regardless of temperature.
Actually this is good thing...as I am now doing some calculations

Absolute Humidity at 60 degrees @ 42 % is 0.00034785 lbs/cu. ft
Absolute Humidity at 85 degrees @ 42% is 0.0007723 "

In this example you can see that the density is twice as much at 85 degrees as it is as 60 degrees. Pretty close the the playing temperature fluctuation that I have.

Now comparing my playing temperature & RH this morning for me:

Absolute Humidity at 62% @58% is 0.0005137 lbs/cu. ft
versus Jim1960's controlled environment
Absolute Humidity at 72% @ 42% is 0.0005157 "

So you can see that while the RH is different...the amount of moisture in the air is almost identical.
(I do not have a dehumidifier...as it only seems to get to these higher percentages for two to four weeks during the year) But I do have a humidifier for when the percentages get low.

So I think I have answered my own question here by doing the math.
I sometimes notice in the winter time when it is in the 60's Temperature...and I get the humidity to around 40% Rh...that the sound is especially crisp.
As shown in the first example...the amount of moisture in the air would then be less, than the norm of 70 to 72 degrees.

If you believe that Sound panels of different densities make a difference for absorption/reflection...then so shouldn't Moisture in the air have some of these same traits? Especially at double the density.

Is it enough of a difference to talk about? Probably not. As others have said...probably everything else makes more of a difference. But on the other end of the spectrum...Maybe recording at 85 degrees where the AH is doubled...might be something to think about. But then again, sound travels faster in warm air. So this puts another twist on the subject matter and leads back to one big circle.

Anyway...this is probably a mood point for most who keep their houses at constant temperatures and constant RH. And there is no way for me to A/B the differences as it happens at different times of the year.

[alohachris]

Aloha,

I agree with Rudy4. The best Relative Humidity % level for recording solo instruments was always within a range of 40-50%.

Another thing to consider: The optimal humidity at which your wooden musical instruments perform optimally.

Here in Honolulu, the average year-round humidity is 63 percent. But we also have a rainy season & altitude variations that can bring that to near 80%. Not as severe as P.I. or Thailand, but it can affect the sound & performance of wooden instruments audibly.

As a former luthier, I had to pay huge electric bills to keep my shop fully humidified & AC'ed year-round so I could ship finished wooden instruments all over the world & have them survive the winters & indoor heating systems. So I was VERY aware of RE humidity & performance.

Ironically, Honolulu's high stable humidity is a great environment in which to build & maintain instruments without seasonal RE humidity issues. As long as you keep those instruments here year-round.

I have an all Koa 00-12 guitar I built 50 years ago. I cut the Koa for it, seasoned it, KD'ed it, built it, & kept it in Hawaii for decades before living abroad for a few years. It played music in over 60 countries, in all seasons, & lived in a HEAVY humidity controlled case that I also built. Two to three cracks opened up along the Koa's dark grain-lines in Switzerland, where I spent a winter, snowed in.

When I returned the Lil Koa to the Islands, I waited til the higher humidity here naturally "tightened up" those cracks & then I repaired them in my humidified shop. They've not moved in over 35 years. So humidity is something we musicians must always consider for performance.

Additionally, I am also a longtime fan of The Symphony & Chamber Orchestra series we have out here. I have heard hundreds of famous Strad, Montagnana & Guaneri viol family of instruments played in the high humidity here.

Often, the players would come out to Hawaii the week before their concert to vacation. Just as Often, the higher humidity here would compromise the sound of those famous wooden instruments (the longer they stayed here). I could clearly hear which ones were not affected by the humidity & which ones were very muted in concert.

I extended that 40-50% RE humidity range to my little recording studios too. Microphones do NOT like high humidity either, especially the ones with metal diaphgrams like the Microtech-Gefell M295's. Something to consider, friends.

So think about your wooden guitar's & mic performances when controlling the Relative Humidity of your space for recording. Vocals too. 40-50% RE Humidity worked for me as a player, luthier, & sometime recordist.

I also liked singing in an RE controlled space too. Sounded better to my ears - that is, when I used to have a listenable voice & great LDC's that were perfect on it.

Just educated opinions & other ways to think about RE humidity, wood, recording, instruments under pressure, voices, seasons & music.

Good Luck!
alohachris

[b1j]

Originally Posted by AcousticDreams

This has nothing to do with the wood moisture, retention. This has to do with how sound reacts in the air with moisture particles. Complete different subject matters.

Absolute humidity and Relative Humidity are two completely different aspects. Relative humidity is about how much humidity the air will hold to a specific temperature. Absolute humidity is how much water is in the air regardless of temperature.
Actually this is good thing...as I am now doing some calculations

Absolute Humidity at 60 degrees @ 42 % is 0.00034785 lbs/cu. ft
Absolute Humidity at 85 degrees @ 42% is 0.0007723 "

In this example you can see that the density is twice as much at 85 degrees as it is as 60 degrees. Pretty close the the playing temperature fluctuation that I have.

Now comparing my playing temperature & RH this morning for me:

Absolute Humidity at 62% @58% is 0.0005137 lbs/cu. ft
versus Jim1960's controlled environment
Absolute Humidity at 72% @ 42% is 0.0005157 "

So you can see that while the RH is different...the amount of moisture in the air is almost identical.
(I do not have a dehumidifier...as it only seems to get to these higher percentages for two to four weeks during the year) But I do have a humidifier for when the percentages get low.

So I think I have answered my own question here by doing the math.
I sometimes notice in the winter time when it is in the 60's Temperature...and I get the humidity to around 40% Rh...that the sound is especially crisp.
As shown in the first example...the amount of moisture in the air would then be less, than the norm of 70 to 72 degrees.

If you believe that Sound panels of different densities make a difference for absorption/reflection...then so shouldn't Moisture in the air have some of these same traits? Especially at double the density.

Is it enough of a difference to talk about? Probably not. As others have said...probably everything else makes more of a difference. But on the other end of the spectrum...Maybe recording at 85 degrees where the AH is doubled...might be something to think about. But then again, sound travels faster in warm air. So this puts another twist on the subject matter and leads back to one big circle.

Anyway...this is probably a mood point for most who keep their houses at constant temperatures and constant RH. And there is no way for me to A/B the differences as it happens at different times of the year.

Here’s a 20-year-old article on the topic on Sweetwater’s site:

https://www.sweetwater.com/insync/ef...ty-live-sound/

Oh-oh, AcousticDreams. It seems that
a) drier air is MORE dense than moist air, and (as a result)
b) dry air absorbs MORE sound that moist air (higher frequencies only, with absorption increasing with frequency).

Why? Airborne moisture (water vapor) is LIGHTER than air. Makes sense when we realize it’s floating in the air.

Mind blown.

[b1j]

Originally Posted by jim1960

I keep my house at 72° in the winter and 70° in the summer.

I want to live in your house. In fact, we sort of did this until getting a $600 PG&E bill last month. At least we have solar for those 106° summer days, but gas in the winter has gotten pricy lately.

[AcousticDreams]

Originally Posted by b1j

Here’s a 20-year-old article on the topic on Sweetwater’s site:

https://www.sweetwater.com/insync/ef...ty-live-sound/

Oh-oh, AcousticDreams. It seems that
a) drier air is MORE dense than moist air, and (as a result)
b) dry air absorbs MORE sound that moist air (higher frequencies only, with absorption increasing with frequency).

Why? Airborne moisture (water vapor) is LIGHTER than air. Makes sense when we realize it’s floating in the air.

Mind blown.

Great research b1j! Very helpful information.

It has the opposite effect I thought it did, yet it offers some insight as to why in some cases lower temperatures with less moisture in the air, makes sound a little crisper?(not sure that crisper is the right word) Possibly denser air means less immediate reflections? Thus a truer sound of the guitar. Something to the effect of acoustic panels.

In other articles, they are claiming cold air out doors, lets the sound travel further.
" If the air near the surface is colder than the air higher in the sky, the top of a sound wave will move quicker than the bottom, tilting and refracting the wave back toward the earth. Sound would leave an interstate or highway, travel up into the sky, and then be bent back down to the surface toward the colder air in this scenario. This implies that the sound will be stronger, and you will be able to hear the traffic noise from a greater distance."

Hmmm? Even in a house we have thermal layers of sorts don't we? Warm air rises to the top.

And in other Articles are claiming that snow:
"a couple of inches of snow can absorb as much as 60 percent of sound. Snow can act as a commercial sound-absorbing foam when it's in that fluffy, freshly fallen state. "

O.K...I got it now.
*What I need is a recording studio that is surrounded in freshly falling Snow. So I won't have to worry about outside noises. So that means I need to pick a location with the largest amount of continual snow fall.
* With high ceilings so I can duplicate the earth's thermal layers, for far reaching sound.
* And record in 60 degree room with 42% RH, for a more dense air. LOL!

Then and only then can I get a perfect recording! it is all becoming clear. ha ha.

[b1j]

I think we’re out far enough on this limb now to begin sawing behind us…

But seriously, we know that sound propagates better and farther in a denser medium (think air and liquid water). So it seems consistent that (denser) dry air would keep more of the sound ringing and less of it absorbed than humid air would.

How that figures into choosing an optimum humidity for recording, I have no idea. I want sound beyond the mic to be absorbed, not to freely travel and bounce off everything. But I don’t want the guitar anywhere near a humid room.

In any case, unless I see data dispelling the notion, I’ll go on believing that this consideration has no material effect, and that I can ignore it.

[jim1960]

Originally Posted by b1j

I want to live in your house. In fact, we sort of did this until getting a $600 PG&E bill last month. At least we have solar for those 106° summer days, but gas in the winter has gotten pricy lately.

Oil has been pricey too but I'm okay with spending a bit extra in order to be comfortable. I loath long pants and to wear shorts around the house in the winter, 72 keeps me comfortable.

[Al Acuff]

This discussion brings to mind an idea I had when I saw that Abbey Road Studios was selling used xlr connectors in lucite blocks here
https://shop.abbeyroad.com/Christmas...ht/7N3L1CPY1RG

So my idea is to go in Abbey Road or similar iconic studio with an air compressor and bottle the air in the studio. Then you sell the air to folks with studios so they can have authentic sounding air. Or you could fill balloons with it and breathe in the creative inspiration...

What do all y'all think? Me... I think it's such a silly idea that it would probably be a money maker.