Palpable "Ripple" in a guitar top - What can it be?

Kh1967 · #1 03-12-2015, 08:01 AM

Hi All,

I have a guitar that has a "palpable" ripple in the top, just off the bridge on the on the low E side. When you run your fingers across it, you can definitely feel it. You can also see it, but it is impossible to photograph, otherwise, I would include a photo.

The guitar is less than a year old and has always been properly humidified; between 45-55%.

In addition, this section of the top moves quite a bit. If the guitar is in its case, at 51%, but I take it out and it is in a room at 46%, the "flex" in this area will move within a couple of hours. It never fully leaves, but it does move quickly.

Kept in the same environment, my other guitars do not "behave" this way. So, I am curious what might be causing this situation.

Any thoughts you might have would be appreciated. Thanks in advance!

duluthdan · #2 03-12-2015, 08:16 AM

What sort of guitar is it? The J-45 I have from 2009 has the nitro finish, and over time has also developed the rippling effect a bit.

Kh1967 · #3 03-12-2015, 08:21 AM

Quote:

Originally Posted by duluthdan

What sort of guitar is it? The J-45 I have from 2009 has the nitro finish, and over time has also developed the rippling effect a bit.

Thanks for asking. The guitar is going back to the builder, so I prefer to keep them nameless for now. That said, the guitar does have a nitro finish, but I don't think that is it. The "ripple" is rather wide and moves quite a bit.

Tobias Music · #4 03-12-2015, 08:22 AM

Hey K, you can always bring it by for a look. Between Pops, Joe, and Third Coast I'm sure we can give you some advice.

Kh1967 · #5 03-12-2015, 08:23 AM

Quote:

Originally Posted by Tobias Music

Hey K, you can always bring it by for a look. Between Pops, Joe, and Third Coast I'm sure we can give you some advice.

Thanks, Paul! I will swing by...I never need an excuse to come see you guys!

rick-slo · #6 03-12-2015, 08:24 AM

Bridge torque bump - normally normal.

However if in doubt have it inspected hands
on - impossible to do it here definitively.

piper_guitarist · #7 03-12-2015, 08:25 AM

Palpable? Can you not see a blemish/bearclaw/anything of the sort?

If so, I'd suspect the finish has something to do with it.

JJO · #8 03-12-2015, 08:28 AM

Was there any sort of pebble tossed or wind to blow?

Glennwillow · #9 03-12-2015, 08:45 AM

Hi Kori,

I have a Gibson Advanced Jumbo Luthier's Choice from 2002 (red spruce over BRW), a wonderful sounding guitar, but during the winter when humidity tends to be on the lower side, the top develops a noticeable ripple in one location. My interpretation is that the woods around the guitar are contracting, squeezing the top wood and creating this distortion. The top has never cracked. I do keep humidity between 30-60%.

I bet the folks at Tobias Music will provide you very good advice.

Best of luck with this,
Glenn

Kh1967 · #10 03-12-2015, 08:53 AM

Quote:

Originally Posted by piper_guitarist

Palpable? Can you not see a blemish/bearclaw/anything of the sort?

If so, I'd suspect the finish has something to do with it.

No blemish of any kind.

Sent from my iPhone using Tapatalk

earri · #11 03-12-2015, 09:23 AM

I've got one too on my slope shouldered Eastman E10SS. I took it to a reputable tech who inspected it and said I've got nothing to worry about. The guitar sounds great!

ewalling · #12 03-12-2015, 09:27 AM

I have a Cordoba C9 Parlor classical that has a mild case of this just behind the bridge. Personally, I'm not worried about it. The guitar seems otherwise in great nick and sounds really good.

Halcyon/Tinker · #13 03-12-2015, 10:49 AM

Sounds like a normal bulge in a lightly built guitar, probably with a Martin style bracing layout.

If you look at the pattern, the two diagonal bars coming off the x's touch on the treble side, leaving an open area behind the low E string where one often finds a bit of a bilge, to lesser of greater extent, in that particular design. That it changes with humidity indicates a lightly built top. If the playing geometry is witching comfortable range, I wouldn't worry overmuch.

Without having seen it of course...

#14 03-12-2015, 10:59 AM

A belly behind the bridge is normal with many acoustic guitars, especially ones with more or less Martin/Gibson style X-bracing. That typically takes the form of a smooth arc behind the bridge. A ripple, or what I think of as a ripple, near the back corner of the bridge is often the result of a loose X-brace. Not a difficult repair, but it should be repaired.

Rodger Knox · #15 03-12-2015, 11:21 AM

Take the tension off the strings, and watch it go away.
Guitar tops distort under string tension, and with a good nitro finish, the distortion is easily visible.
Humidity variations also distort the top, but my guess is what you're seeing is from string tension, and is completely normal.