Humidity and good acoustic guitars

DevonChris · September 2017

Teyeplayer said:

Just noticed this in the classifieds and thought it might be of interest to you as you'd mentioned a furch:
http://thefretboard.co.uk/discussion/111770/fs-furch-stonebridge-d22-cm-and-schertler-amplifier#latest

Thanks for your heads up, which I've just noticed! (my fault).

I saw that Furch for sale, but it went very quickly, unfortunately.

guycp said:

Our house (old granite farmhouse in far West of Cornwall) always has high humidity! A wet summer is worse. Currently at 78% in my office/music room.
I have had Bourgeois, Martins, and Gibsons and Santa Cruz that have been adversely affected by high humidity. Higher humidity is not normally a problem for cheaper heavier braced or laminated acoustic guitars, but can be a big problem for hand built guitars that were built in workshops with 35 -45% humidity (i.e. many hand made high end acoustics made in the USA). Not only do the tops swell up altering the action and distorting the top around the bridge, but the guitars loose their tone and can become woolly and dead sounding.
Best to get a decent de-humidifier and put it in the same room as the guitars and keep the door shut. I do this and manage to keep the humidity down to around 60%. I also use re-useable cotton bags of silica in each guitar case, which change colour when wet.
I've found that the best option for damp conditions is to have a room with a dehumidifier that you store your guitars in.
Also get a decent hydrometer so you can keep an eye on the humidity level.
Low humidity is not normally a problem in the UK

Thanks for your excellent comment, @guycp ; With all the wet weather we've had recently our hygrometer is currently showing 70 - 76% humidity levels. Not good.

Thanks for your advice about a dehumidifier and the silica bags. I am really tempted to get a high end acoustic, but would hate to see it experience those issues that you mentioned. I might have a chat with Mansons in Exeter to get their views on this too.

Fantastic help and advice from everyone in this thread. Thanks.

Adji · September 2017

Some great advice already in this thread.

A de-humidifier and hygrometer is essential imo.

It is a little 'gadgety' but we have a pretty cool digital hygrometer (amongst other things) that links to your phone so you can monitor remotely.
http://www.planetwaves.com/pwProductDetail.Page?ActiveID=4115&productid=1074&productname=Humiditrak___Bluetooth_Humidity_and_Temperature_Sensor

I sometimes do some very basic workshops on maintaining acoustic instruments and touch on humidity.
IIRC the average humidity varies between about 60 and 80 per cent in the UK so low humidity is likely not going to be an issue THAT often.

Here are some findings from research I have done (including speaking to luthiers) on some of the problems that humidity can cause, it might be useful:

----------

Melting Glue

Excessive heat, resulting in low humidity / heavy moisture loss, could cause the glue to weaken or literally melt in your instrument.

The results can vary from a slightly ‘sliding’ bridge to cracks in the guitar where the soundboard joins to the sides. Or, in extreme situations, the entire soundboard can be pulled away from the body of the guitar.

It can also adversely effect other parts of the guitar, the frets may become loose in their slots and start to come out of the guitar.

Swollen Top

The top / soundboard of your acoustic guitar should be flat (unless specifically designed not to be). A swollen or bulging top usually indicates there is too much moisture in the wood (due to high humidity) and the wood has literally swollen. Often next comes cracking at the glue joints.

Sharp Fret Ends

Sharp fret ends can be a sign of a guitar that is too dry. The neck / fretboard has become so dry that it has started to shrink or contract, leaving the metal fret ends exposed.

Sunken Top

In direct opposition to the swollen top, a sunken top suggests that the soundboard is too dry and the wood has started to shrink. It is very likely that if you can spot this on your guitar, cracking or breaking at the glued joints is not far away.

“Loss of Tone”

Tone is incredibly subjective so this should not be the only defining factor.

An overly dry guitar is often said to sound brittle, tinny, or thin.

An overly wet guitar is often said to sound tubby, muddy or flubby.

Lewy · September 2017

Adji said:

Some great advice already in this thread.

A de-humidifier and hygrometer is essential imo.

It is a little 'gadgety' but we have a pretty cool digital hygrometer (amongst other things) that links to your phone so you can monitor remotely.
http://www.planetwaves.com/pwProductDetail.Page?ActiveID=4115&productid=1074&productname=Humiditrak___Bluetooth_Humidity_and_Temperature_Sensor

I sometimes do some very basic workshops on maintaining acoustic instruments and touch on humidity.
IIRC the average humidity varies between about 60 and 80 per cent in the UK so low humidity is likely not going to be an issue THAT often.

Here are some findings from research I have done (including speaking to luthiers) on some of the problems that humidity can cause, it might be useful:

----------
Melting Glue
Excessive heat, resulting in low humidity / heavy moisture loss, could cause the glue to weaken or literally melt in your instrument.

The results can vary from a slightly ‘sliding’ bridge to cracks in the guitar where the soundboard joins to the sides. Or, in extreme situations, the entire soundboard can be pulled away from the body of the guitar.

It can also adversely effect other parts of the guitar, the frets may become loose in their slots and start to come out of the guitar.

Swollen Top

The top / soundboard of your acoustic guitar should be flat (unless specifically designed not to be). A swollen or bulging top usually indicates there is too much moisture in the wood (due to high humidity) and the wood has literally swollen. Often next comes cracking at the glue joints.

Sharp Fret Ends

Sharp fret ends can be a sign of a guitar that is too dry. The neck / fretboard has become so dry that it has started to shrink or contract, leaving the metal fret ends exposed.

Sunken Top

In direct opposition to the swollen top, a sunken top suggests that the soundboard is too dry and the wood has started to shrink. It is very likely that if you can spot this on your guitar, cracking or breaking at the glued joints is not far away.

“Loss of Tone”

Tone is incredibly subjective so this should not be the only defining factor.

An overly dry guitar is often said to sound brittle, tinny, or thin.

An overly wet guitar is often said to sound tubby, muddy or flubby.

Great info (although I slightly disagree that an acoustic soundboard should be dead flat...I subscribe to the opinion that no belly at all is the hallmark of an over-braced guitar

)

I can vouch for the Humiditrak, it's a great bit of kit and the app is very good. I've been able to evaluate exactly how much protection my cases give to fluctuations in temperature and humidity and it's meant I haven't had to worry about it.

DevonChris · September 2017

Thanks @Adji and @Lewy

Our humdity today is 63% so it looks like we are bouncing around the 60 - 80% range. That Humiditrak looks great. I guess you keep it in your guitar case (along with the guitar of course!) and monitor it remotely using your phone.

Are there any ideal humidy ranges that we should be trying to achieve to prevent damage to a top end guitar?

Lewy · September 2017

DevonChris said:

Thanks @Adji and @Lewy

Our humdity today is 63% so it looks like we are bouncing around the 60 - 80% range. That Humiditrak looks great. I guess you keep it in your guitar case (along with the guitar of course!) and monitor it remotely using your phone.

Are there any ideal humidy ranges that we should be trying to achieve to prevent damage to a top end guitar?

All my opinion....

There's damage, and there's sub-optimal performance.

For damage, I think there's a floor of about 40-45% RH that you want to make sure you don't go below for any length of time. The ceiling is quite high - your guitar is probably not going to sustain actual structural damage until it's living well above 60% RH all the time, and then you'll possibly still be fine (as others have reported here).

But a typical high end US -built guitar won't be playing or sounding it's best up there. The top may belly significantly, meaning that to improve playability you need to lower the saddle. That's fine, except that affects a critical bit of guitar geometry...the height of the strings off the soundboard. People don't talk about this much but it's really important to getting the most out of a good guitar. It affects the way torque is applied to the top and therefore the volume and response of the guitar. The ideal is generally about 1/2" distance between the bottom of your low E string and the soundboard right in front of the bridge. Now, if you have to drop your saddle to restore playability (because excess humidity has caused an excess belly), then the more you drop that string height off the soundboard, the more you're deviating from how that guitar was built/braced/voiced to work. So that's one thing. Another is the fact that over-humidified guitars can sound woolly/muffled and it can all feel like a bit of an effort. Chances are, what attracted you to a high end guitar in the first place is the way the notes seemed to literally spring out of it. Wet guitars tend not to sound or feel like that.

As I say, it affects different guitars in different ways. My Collings guitars sound and feel best at 45% RH, I can tell a difference if they've been around 55% RH for any more than a day or so. No chance of damage there, but they're not the guitars they can be above there (or the ones I incurred significant debt to acquire!). For the sake of a couple of hundred quid on a good dehumidifier, why settle?

Of course you can't keep guitars in a controlled environment all the time. I take mine out to festivals where they'll be in a cold tent at night and probably be around a campfire etc. Who knows what the humidity is in a pub or club I'm playing at, and what would I do about it if I did know? But I can control where they spend most of their time and that's worth the effort as far as I'm concerned.

EDIT: Sorry, and yes that's precisely how the Humiditrak works.

DevonChris · September 2017

Chances are, what attracted you to a high end guitar in the first place is the way the notes seemed to literally spring out of it. Wet guitars tend not to sound or feel like that.

Definitely.

I haven't bought an acoustic yet, but a bit of me is wondering if I'd be better buying a Yamaha LL16 level guitar rather than going further up market, though I've no issue buying another de-humidifier for the room where I'd keep the acoustic (in its case with a Humiditrak).

I think I'll give Brook Guitars a ring tomorrow as they are based about 10 miles from me and their humidity levels will be just as high, if not higher, than ours.

@Lewy - great information in your comment. Thanks very much.

Lewy · September 2017

A good case will be sufficiently sealed to mean you won't need to run the dehumidifier while the guitar's in the case, by the way.

For example, unchecked the RH in my music room regularly gets up around 60% if I don't run the dehumidifier. The inside of my cases rarely gets above 50% regardless of what's going on outside. The dehumidifier only takes 5 mins or so to get the RH down so I just run it for a bit before I settle down for a play.

ToneControl · September 2017

Assuming you keep guitars away from radiators, fires and sunny windows (many don't):

in modern UK houses, the only problem is low humidity in the winter, it can drop to under 30%
over 65% is dodgy too

I'd recommend buying 2 or 3 cheap hygrometers and trying them around the house
you may find one room not as damp during damp periods, e.g. an airy room that does not have much of an exposed external wall

Humidity will be determined by your house construction, not geographical location in the UK, the reasons are down to physics, and I will skip them since they are already on this forum in other posts

It may be that you need a winter room for guitars, and a summer one

a cello has a very different design to a guitar
top-brand acoustic guitars are very sensitive to humidity, and they can be hard to play, as well as sounding worse.
more extreme variations can cause damage, as noted, but normal variations will diminish the pleasure by putting the guitar out of tuning and changing the action, as the neck varies from one week to the next

In my house, the only risk is low humidity
Therefore I have 2 humidifiers, driven by a hygrostat, which switches them on below 45% RH
It's the size of a mains-socket-timer, with a UK plug socket on the front

They have another mode, which is intended for your problem, where they would switch on a dehumidifier above a certain humidity level (e.g. 55%)
I'd recommend one of these for you. Tracking humidity is not as effective as controlling it.
If you get it right, you can leave the guitar out of its case all the time, and play it more

ToneControl · September 2017

For good value excellent UK-made guitars, I'd recommend Avalon, ring up the workshop, since all the dealers are outside the UK

Adji · September 2017

Lewy said:

Adji said:

Some great advice already in this thread.

Great info (although I slightly disagree that an acoustic soundboard should be dead flat...I subscribe to the opinion that no belly at all is the hallmark of an over-braced guitar )

I can vouch for the Humiditrak, it's a great bit of kit and the app is very good. I've been able to evaluate exactly how much protection my cases give to fluctuations in temperature and humidity and it's meant I haven't had to worry about it.

Glad it works for you man.

That's an interesting thought and not one I've really considered about bracing. (I'm fairly new to having any 'real' understanding of acoustic guitar construction). I would IMAGINE that over-bracing is generally found in cheaper guitars or those with less experience building them? I'd imagine finding the balance of sufficient structural support vs ability of the top to 'breathe' a really difficult one.

Thanks.

DevonChris · September 2017

They have another mode, which is intended for your problem, where they would switch on a dehumidifier above a certain humidity level (e.g. 55%)
I'd recommend one of these for you. Tracking humidity is not as effective as controlling it.
If you get it right, you can leave the guitar out of its case all the time, and play it more

We have a dehumidifier like this in our cellar. It works well.

This has turned out to be a fantastic thread with some really great advice and help. Thanks everybody

ToneControl said:

For good value excellent UK-made guitars, I'd recommend Avalon, ring up the workshop, since all the dealers are outside the UK

I've come across Avalon guitara before. They are indeed exellent. I will phone them.

I wonder if UK made guitars are less susceptible to high humidity than USA made ones

Lewy · September 2017

Adji said:

I would IMAGINE that over-bracing is generally found in cheaper guitars or those with less experience building them? I'd imagine finding the balance of sufficient structural support vs ability of the top to 'breathe' a really difficult one.

It's a bit of a relative term...for some players, anything more than scalloped forward shifted bracing is too much, but other players might prefer something a little more sturdy. Obviously it all interacts with the species and thickness of the top too.

Most people who buy high end acoustic accept that if they keep them for a long time they are likely to need a neck reset in the future. Usually nothing to do with the neck moving, much more often to do with the top settling into a belly and having to adjust the neck angle to compensate. Martin used to do these under warranty regardless of how old the guitar was but they've stopped doing that now, unless it's needed very early on.

Rat_Salad · August 2021

Sorry to drag up an old thread, but I'm having a lot of trouble with a Taylor I bought a couple of years ago. It lives in a granite cottage in Cornwall, with humidity ranging from 60 (Winter) to 85 (Summer). Today the r/h is 82. The top/bridge has arched up and the action is pretty much unplayable. Truss/Neck is perfect, but the raised bridge has done for the action.

The strange thing is, that it sits next to a cedar Simon & Patrick, which is totally unaffected with a perfect action. There are four other guitars in the house, ranging from 30 year old solid-bodies to newer acoustics - they're all perfect.

In the same room as the Taylor is a 135-year-old Bluthner piano, suffering no ill-effects.

It seems that the Taylor is highly sensitive to RH, but everything else is not !

I'm going to let it live in its case for a couple of months with some silica packs, to see if that will sort things out, either that or I'll find out whether it's too far gone. It's not very high-end in the Taylor range (about £1,500) but it still stings that I only got to play it half a dozen times before the action made it remain in its stand ever since...

richardhomer · August 2021

Rat_Salad said:

Sorry to drag up an old thread, but I'm having a lot of trouble with a Taylor I bought a couple of years ago. It lives in a granite cottage in Cornwall, with humidity ranging from 60 (Winter) to 85 (Summer). Today the r/h is 82. The top/bridge has arched up and the action is pretty much unplayable. Truss/Neck is perfect, but the raised bridge has done for the action.

The strange thing is, that it sits next to a cedar Simon & Patrick, which is totally unaffected with a perfect action. There are four other guitars in the house, ranging from 30 year old solid-bodies to newer acoustics - they're all perfect.

In the same room as the Taylor is a 135-year-old Bluthner piano, suffering no ill-effects.

It seems that the Taylor is highly sensitive to RH, but everything else is not !

I'm going to let it live in its case for a couple of months with some silica packs, to see if that will sort things out, either that or I'll find out whether it's too far gone. It's not very high-end in the Taylor range (about £1,500) but it still stings that I only got to play it half a dozen times before the action made it remain in its stand ever since...

Taylors have bolt on necks and their authorised service centres can quickly perform a neck reset which should give a playable action. The best bet is to contact Taylor - in my experience they are very responsive.

Axeal · August 2021

I had a very expensive guitar ruined by leaving it in my high humidity cellar. The top bellied big style. It affected the sound and just ruined the feel on the neck. That was a solid spruce top - the laminate guitar I still have didn't budge. My strat never alters neither, but another solid body I have does at the neck.

My advice would be to be very careful - play the guitar in the cellar, but store it elsewhere.

Don't assume it will probably be O.K - when its too late, it could well be beyond economical repair and you will just "fall out" with the guitar and get rid like I did and feel really miffed.

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Humidity and good acoustic guitars

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