Action adjustments due to seasonal change...

ski

Hey All,

I've had my Geronimo Mateos guitar since the winter and the action was originally setup to be about 3mm at the 12th fret for the low E string. The action is now pushing 5mm, which is knocking the intonation a little out of whack...not to mention being more difficult to play.

How do I get the action back down? Do I need a few different bridges to use at various times of the year? Something else? I don't want to mess with the truss rod because the relief seems fine. And I'm never comfortable making truss rod adjustments anyway.

Thanks,
ski

Bob Holo

That sounds backwards, ski.... typically in the winter in the Northeast you folks have a lot of cold weather and heaters that dry the air out and you'd be experiencing a lower action. Also, a 3mm to 5mm swing is pretty flippin unusual though I guess that guitars change more during their first year of life as the wood sort of settles... and add to that the fact that you folks on the East coast have insane barometric swings... maybe it's not unprecedented. Get something with a humidity gauge and try to regulate the humidity of the guitar to ... well... something near 40+ +/- 5% and see if the action gets better. If not - then you need to figure out what's going on. It could be anything from - maybe you loaded big strings on it and pulled the neck up - so go back to argentine 10's or 11s and pray for lenience from the guitar gods that it will straigten itself, maybe there is too much relief in the neck (does it have a truss rod and did you adjust it or have it adjusted?) or it could be the guitar simply settling-in. If that is the case, then yes, getting the bridge lowered / new bridge would be OK.

But the fact that it moved 2mm and in the opposite direction of what I'd expect... makes me wonder. It might not hurt to take it to a good (not guitar center etc.) guitar tech and ask him to take a look at the neck and tell him what happened and ask if he sees anything unusual. Without looking at it I can't really tell what's going on and so if I tell you what I think is the likely situation... and it turns out that it's being caused by something that has gone wrong - I could wind up giving you the exact wrong advice.

Oh, also - make sure you're measuring action right - between the top of the 12th fret and the bottom of the string... if you're including the height of the fret and the thickness of the low E string it'll add a bit more than 2mm. Good luck

ski

Thanks Bob. I agree with everything you said and have to admit I'm a little concerned by the change. Josh set the guitar up for me and installed a custom bridge when I got it last winter. I did measure the action the correct way and it was still in check when I had it with me at Django in June this past summer.

I also was using a soundhole humidifier - one of those sponge things - during the late winter and then stopped as the humidity in the region started to go up during the warmer weather. Lastly, I've kept the guitar mostly in its case since Django in June. I don't know if any of these things would contribute to the increased action?

The relief seems ok (maybe?) when I measure the string height at the 7th fret while pressing down the low E at the 1st and 13th frets...a little less than .79mm. Is this too much relief?

I'm going to leave the guitar ouf of its case, too, since the action does usually get lower during the colder months as you pointed out.

Thanks for the info - I'm hoping this can be fixed....

Bob Holo

You probably need to get a handle on how much of this is from humidity. Nothing you've said would cause the action to vary that much or in that direction. The relief is a little high for my taste, but not unreasonable. I have a few vintage rigs with that much relief and they play fine with normal actions. I suppose it's possible that your truss rod is a 2-way rod and loose to the point of not supporting the neck and the string tension is pulling the neck into a bow which you're perceiving as relief... but that's fairly unlikely... and it doesn't sound like you've done anything odd to the guitar, so if I had to guess, I'd say it's the ol' "first year of a guitar's life" movement combined with humidity changes that may be more drastic than they first appear.

In Oregon the humidity is really stable - raining hard one day at 46% and dry as a bone the next day... but the humidity only drops to 43%. But at DJiJ this past year I setup that guitar for Robin the day before the concert - near 80% humidity... the day of the concert it was 29%... that was a real eye opener for me about how hostile some seemingly benign environments can be toward guitars.

Here's some info on how to get a handle on your humidity without breaking the bank... Radio Shack digital hygrometer with instructions on how to calibrate it. http://www.cigargroup.com/faq/#6.0 If you get the humidity under control and the problem is still there - then it's probably time to have someone take a look to make sure there's nothing wrong with the guitar causing this (look for obvious things - warps/twists/pipes in the neck... warps in the waist of the guitar that might indicate that the body itself is not stable... bridge that is significantly rearward or backward of its intended position roughly between the mustaches - if the bridge is sitting higher on the bombe/pliage than intended it'd raise the action... but really - these things would be way obvious. You'd see them and they'd manifest themselves in other sound/playability problems as well.

ski

Thanks Bob. I think I have a somewhat reliable luthier I can bring the guitar to for a setup. He can adjust the truss rod (I don't trust myself, especially with the small oval hole access) and maybe assess the rest of the guitar structurally.

That being said, I really don't think there's anything wrong with the guitar. Aside from the high action, the guitar sounds great and plays relatively well. I've left the guitar hanging on the wall the past few days and will continue to keep it there for a while to see if the neck relief does anything in the meantime.

ski

I thought I'd give an update on the action situation. I left the guitar out of it's case for a few weeks and the action gradually came back down to about 2.5mm at the 12th fret. Looks like extreme changes in humidity must have been the cause. The guitar plays and sounds great!