Curing Acoustic Set Up Ills.

[Dreadman]

Sorry I'm late to the party. I get lost in here sometimes.

Everyone's got good advice so I don't know how much more I can add. SVL's guitar is definitely seeing the effects of low humidity. Here's a quick list of low humidity related problems:

1.) Sunken top - A "flat top" guitar isn't actually flat. The top and back are radius-ed, meaning that they are like guitar shaped sections cut out of a big ball. When humidity gets low wood shrinks, primarily in the cross-grain direction. That means the width of a guitars top tries to get smaller. First it flattens out (loses it's dome shape), then the area between the soundhole and bridge dips down

2.) Cracks - If left dry long enough the top cracks along the grain. This is because the sides are holding the edges of the top while it shrinks so it gives somewhere in the middle, like a paper towel being pulled apart by the edges.

3.) Humped neck - When overly dry the fretboard (and to some extent, the neck) wood shrinks too. The hump where the fretboard meets the body isn't actually high, it's the rest of the fretboard/neck that has gotten low. The area in question stays high because the heel is under it and that makes more wood that would have to dry out before deforming.

4.) Neck warps, twists, bows, etc.... - Wood is a dynamic material and no two pieces are alike. When over dried (or, to a lesser extent over humidified) it can do all kinds of unexpected things. If the grain curves ever so slightly then drying it out could cause exaggeration of that curve. These issues aren't especially common in comparison to the three above so I won't go on and on.


The cure for all of this (if the instrument hasn't developed a permanent defect) is simply - add moisture (as noted in previous posts). This can be done by either adding humidity to the room that the guitar lives in or adding humidity to it in it's case (room humidifier vs. case humidifier). The trick is to be patient and add moisture slowly. Several weeks is typical so don't be discouraged after a week.


Taylor guitars are built with especially thin tops (lending to their signature sound) and that's why they must be cared for especially well. A lot of people bash Taylors for this reason but it's not fair. Thin tops are a way of pushing the envelope and, just like with cars, if you're going to go high performance there are extra precautions. Speaking of Taylor, here's Bob Taylor himself explaining about humidity in guitars - http://www.taylorguitars.com/see-hear/ Watch the video called "Humidity: The Symptoms". If you look around there there is also a video called "Understanding Humidity" - both are must see material.

SVL - if re-humidification doesn't fix your hump you'll have to consider having the frets (at least the few at the neck/body) leveled and crowned. It's not too expensive, as long as the rest of the frets are in reasonable condition a luthier or tech can probably lower the offending frets for less than $50.

I didn't hear any open string buzzing in your (very pleasing) recording but if you say it's there I believe you. Do this check - Hold down the low E string at the 3rd fret and look how close the string comes to the top of the second fret. You should be able to just slide a piece of paper between them (about .005"). If it's too close to see tap on the string above the second fret wire and listen for a "clinking" sound. If you hear it there's clearance and your nut slot is fine. Repeat this on all six strings. If your nut slots are indeed low (strings touching the second fret during this test) let us know and we'll hook ya up with some DIY nut raising info.

I may add more later after I re-read this and see what I forgot. LOL

[Dreadman]

Oh yeah - 40% - 60% relative humidity is ideal for acoustic guitars. Higher RH will cause expansion of the wood which will raise the action, deaden the sound slightly and a few other minor things. Very little risk of damage though. My guitars have spent many summers in 80% - 90% RH with very little lasting effect. At the other end is where damage comes from. 20% RH for any extended period of time is a guitar killer.

In reality, every acoustic guitar owner should own at least one digital hygrometer (the needle type aren't as accurate). $10-$20 gets you a lot of information that's paramount to your guitars health.

[sunvalleylaw]

Ok here is a link to some pics. I hope I got the angles right. If not, let me know I and I will re-shoot. I put it up quick on a .Mac page without editing well the text for the page, so kindly ignore any gibberish on the page.

http://web.mac.com/sunvalleylaw/Site/Last_Import.html



So it sounds like getting a hygrometer is in order, and making a coupla sponge thingies, and keeping moisture in them. No good letting them dry out, huh! I did the check you recommended Dread, and it is a close call on a couple. Paper will slide through, but I have to push on a couple. G, Low E, and high E seem a little sticky on the test. Also, though I get clinks on those strings, not very loud ones. We shall see how re-humidifying works.

Thanks for your 2 cents! Done...I'm ordering one of those gadgets right now thank you for your assessment sir.

Btw Stephen S.T. Esquire I didn't mean to hijack your thread sorry!

I don't consider that really a hijack, it is germane. Besides, what's a little hijacking among friends. Sounds like we are both in the market for some sponges, baggies or soapboxes and digital hygrometers. Cheap insurance I'd say.

[Dreadman]

I could see the hump right away in the first two pics. The fretting problem high on the neck that you mentioned is the dead giveaway though.

I'd prescribe 50%-70% RH for two weeks, maybe three. Use either a room humidifier with hygrometer in the room or a couple case humidifiers with a hygrometer in the case.

If you do it in the case make sure the fretboard and one humidifier are in the same "air space". The other humidifier should be near the body, preferably in the soundhole. In some tight fitting guitar cases you can't humidify a fretboard effectively because the fretboard is covered by the plush case top. A big chipboard case would be better.

If you humidify a whole room just leave the guitar there. If it's in a case re-wet the humidifiers daily and check the progress.

Here's a cool litle trick - Tune it perfectly before you start humidification. As the wood absorbs moisture it will grow in size and the pitch of the strings will go up. You can re-tune it every day or two and get a feel for how much water it's absorbing. When the strings pitch stays in tune for a few days in a row you know the wood is at an equal humidity as the environment (no more growth). Of course before that point you'll probably have already noticed the hump is gone (or lowered significantly).

(EDITED TO ADD) You'll also notice the action going up during humidification. This is the top regaining it's domed shape (therefore lifting the bridge back up) and it's just what you want. If we can get the hump out of there, and you'd like to, we'll go through a set up next.

[Dreadman]

If you're getting the clinks then your nut slots are probably fine. It's okay if the paper is tight, as long as it goes. All you're looking for is that the string isn't resting on the fret.

(EDITED TO ADD) Just a note - those who play acoustics hard will want this "nut action" a little bit higher than a sheet of paper, just like they'd want the rest of the action higher. Hard strums cause the strings to vibrate in a wider path so you want the frets a bit further away to prevent buzzing.

[sunvalleylaw]

Thanks Dreadman. I won't be able to do whole room so case humidification it is. My case is a large archtop:

http://www.musiciansfriend.com/produ...ase?sku=541694

(BTW, for the money, it is a nice case).

Getting a humidifier in the same airspace as the fretboard will be interesting. I could put one up by the headstock, and one in the sound hole for sure.

That trick you mentioned is interesting. I had noticed before that when we travel to western Washington State each summer, my guitar would go sharp on the way over, and flat on the way back. I figured it was due to this. After about 3 days, it would steady itself. But even after several days this time, the hump did not go away (though it lessened some), and it was still a buzzy. More than the year before when I also brought it on the trip. It was hugely humid too this last trip. You know, when your clothes get damp feeling just hanging out.

I could see the hump right away in the first two pics. The fretting problem high on the neck that you mentioned is the dead giveaway though.

I'd prescribe 50%-70% RH for two weeks, maybe three. Use either a room humidifier with hygrometer in the room or a couple case humidifiers with a hygrometer in the case.

If you do it in the case make sure the fretboard and one humidifier are in the same "air space". The other humidifier should be near the body, preferably in the soundhole. In some tight fitting guitar cases you can't humidify a fretboard effectively because the fretboard is covered by the plush case top. A big chipboard case would be better.

If you humidify a whole room just leave the guitar there. If it's in a case re-wet the humidifiers daily and check the progress.

Here's a cool litle trick - Tune it perfectly before you start humidification. As the wood absorbs moisture it will grow in size and the pitch of the strings will go up. You can re-tune it every day or two and get a feel for how much water it's absorbing. When the strings pitch stays in tune for a few days in a row you know the wood is at an equal humidity as the environment (no more growth). Of course before that point you'll probably have already noticed the hump is gone (or lowered significantly).

[Dreadman]

That case will probably cover the fretboard too tightly. You could always do it in a garbage bag or cardboard box. Be creative.

[luvmyshiner]

In some tight fitting guitar cases you can't humidify a fretboard effectively because the fretboard is covered by the plush case top.

One thing I've tried is to take a piece of heavy paper, and cut it down to size to place over the fretboard when you close the case. It makes, like a little tunnel to help keep the case top from sealing off the fretboard.

[Tone2TheBone]

Wow these are really good tips. A veritable cornucopia of information. My daughter's taking violin lessons so her teacher also informed us of the effects of this dry climate here at home so yeah care of expensive violins is just as important as care of expensive guitars.

[mrmudcat]

Thats what I like to see some rocking in the accoustic house!!!!! Great posts by every one!!!

[sunvalleylaw]

I looked again at the case last night as I loaded in a freshly made "Sponge in a bag" humidifier and re-wetted the Herco. The arch over the body of the guitar leaves some room, and I bet combining that with the paper trick might work. I may also trash bag it for a while to be sure. I put the sponge in the sound hole, in the body, and the Herco between the body and the neck where it joins. There is a cavity there with some room. I may put another sponge up in the cavity for the head stock also. (Just to get the thing goin, like mojo nixon says.) I have to go find a digital hygrometer too, or order one in. I am not too worried about over humidifying right now as the climate is very dry right now, and the heat is being used in the house, as it is still getting to single digit temps at night.


Now, just because this thread is generating so much good info, let's have the tips on low nut slots, and other set up tips for our acoustic git-boxes. Thanks guys for all the participation.

EDIT: The increased humidity by using the sponge trick and doubling up with one sponge humidifier, and the Herco pill box kind I already had, is already starting to make a difference. Thanks guys, I am really encouraged! I had been bummed about my first guitar that my wife had gotten me. I am going to get that thing humming again!

[peachhead***]

Wow...what a great thread. I have been thinking about the humidity, or lack of it, in the house for the last week- great timing. A hygrometer is definitely on my must have list.
Thanks for the excellent info!

[mrmudcat]

Dread is good to us peaches brother.

[wingsdad]

Like you, SVL Steve, I'm in a high desert, mine that of Southern California about 100 miles inland from LA, at about 3,500' above Sea Level, and the old Albert Hammond song rules: about 6-8" of rain a year, most of that in a couple of downpours. RH outdoors is seldom over 15%, and the RH in the house is never over 35%, and during winter, forced-air heating drops it to 25-30%.

While D-man is totally right about Taylor's thin tops (truly intentional as part of what delivers their reputed sound), the trick with Taylors is that their built about 5 miles from the Pacific, where it's nice and damp and the wood is pliable. When they come inland, like up here, they inevitably end up frustrating their owners, even those who think they're doing enough with a case humidifier, with cracking tops. They are that sensitive. I've seen quite a few of them like this...the ones that end up in pawn shops or at the local luthier (the guy who rebuilt my D40). We have a Taylor dealer here. He sells about 10 a year.

I subscribe to not casing my guitars so as to not: (a) smother the wood (b) allow any chance of heat or residual humidity from a case or soundhole humidifier to buildup, leading to possible permanent over-humidification swelling damage, and last, but not least, (c) to encourage me to grab one at will and play it.

So years ago, after nearly losing my ancient Guild D40 to this desert, its top's braces actually coming unglued on one big chord strum, leading to a $450, 3-month rehumidification and restoration, I decided it best to keep my acoustics and hollow/semi-hollow electrics in a 'humidor'. (The Colorado Rockies may have heard about it, and built one to keep their balls from getting too lively )

I know my old friends from the WGF have seen this thing that I built - a crude, inexpensive, but effective cabinet in my den/music room's small walk-in closet. The closet's temp stays at about 68-70 degrees F, controlled by leaving the door open in winter during the day when the heat's not running and closing it in summer a/c months.

I run a little $30 cool-mist room humidifer loaded with distilled water for about an hour or so every couple of nights (I check nightly when I pull a guitar to noodle) to keep the closet's RH between 45-50%. I've got an analog hygro & thermo on top of the cab, and a Planet Waves Digital hygro/thermo thing inside it. The cabinet's bi-fold doors do not seal tightly, so air and humidity flow through under control.

Each roundhole acoustic has a Kyser Lifeguard in its soundhole (the Guild has a super-Dampit hanging inside to supplement that) and the f-hole electrics have smaller, thinner Dampit 'worms'. All of these are charged with distilled water in a weekly Saturday or Sunday ritual .

The rest of my less-sensitive guitars hang on the walls in the room (or the closet)...with dampits in the tops of the non-solids.




Since I got into this system, I swear...I haven't had ANY of the problems mentioned here with my acoustics. And most are all solid woods. I have to keep an eye on the Guild, but I've helped her out by stringing her for Nashville tuning...all light gauge strings (only the .024 6th is wound) to keep the tension on her top at a minimum (besides giving me a great permanent use for her).

[Tone2TheBone]

Alright guys...do you think this hygrometer is a good one?

http://careysmokeshop.stores.yahoo.n...ygrometer.html

[luvmyshiner]

Looks just fine to me Tone.

[Tone2TheBone]

One more Shiner...

http://oasishumidifiers.com/hygrometer.html

This one has the min/max button. I don't know a fuggin' thing about these things please excuse my ignorance! 5 dollar price difference. I suppose either would do? I did get one of those Planet Waves humidifiers though.

[luvmyshiner]

Either one looks great Tone. I'd probably save the five bucks and spend it on beer though.

[Tone2TheBone]

Either one looks great Tone. I'd probably save the five bucks and spend it on beer though.

Mmm you got a good point there. That'll buy me a Shiner or 2!