*****Eastman E6D-TC belly******

[hwooddell]

I just got a new Eastman E6D TC. This is my first Eastman guitar. It appears that there is kind of a belly behind the bridge. I know that guitars aren’t truly flat tops, but I wonder if this is normal. I have been keeping the D’Addario Humidipaks in the case but can’t get the RH below about 62. I just want to know if I need to send it back or not. Any guidance and info is appreciated! Thanks! This is my first post on AGF and I can’t seem to figure out how to post a picture of it.

[warfrat73]

Most modern guitars have a bit of an arch built into the top. A little bit of top deflection under string tension is also normal.

To post pics without becoming a charter member you have to host them elsewhere and then link to them. Or you can use the TapaTalk app, which is really the easiest way and how i post pics most of the time.

[martingitdave]

RH of 62 is high. Eastman usually builds their guitars to hold up in high humidity environments. But, there may be some bellying. Take pictures, talk to your retailer.

[warfrat73]

Yeah... 62 is high, and Humidipaks are technically are supposed to moderate humidity in both directions, but they're not really good at drying things out... take them out and put some silica packets in there for a few days.

[Tero]

I have Eastman E8D TC and usually room moisture at 45-55%.

But, if more (over 55-60%) then I can see "bellying".

Keep your Eastman a bit more dry...

[ljguitar]

Originally Posted by hwooddell

I just got a new Eastman E6D TC. This is my first Eastman guitar. It appears that there is kind of a belly behind the bridge. I know that guitars aren’t truly flat tops, but I wonder if this is normal. I have been keeping the D’Addario Humidipaks in the case but can’t get the RH below about 62. I just want to know if I need to send it back or not. Any guidance and info is appreciated! Thanks! This is my first post on AGF and I can’t seem to figure out how to post a picture of it.

Hi hwooddell
First of all, hello and welcome to the forum!!

Yes bulge is normal, and common.

Acoustic guitars have bellying behind the bridge (toward the tail) and it's more pronounced on the bass side due to the greater pull of the bass strings (versus the trebles).

There are over 150-180 pounds of pull on the top and bridge of acoustic guitars due to steel string tension (heavier strings more tension). The more lightly built a guitar is, the more tendency toward bulge. It's not dangerous and better builders build it into the design.

My Olson is a true 'flat top' and it has some bulge (at age 32). It's been checked by a luthier, and I spoke to James Olson about 6-7 yrs back about it, and he assured me (I had pictures) it's fine and normal, not dangerous and doesn't require a Bridge Doctor.

I also has Michael Bashkin look at it, and he concurred with Jame's assessments.

My Bashkin was built with a cambered top, and it has some bulge (as do my other 4 acoustics). If you lay a straight edge behind the bridge on most acoustics there is measurable bulge visible.

Not dangerous, and expected.

If a brace has turned loose that may contribute, but that's pretty rare.

Some less than scrupulous techs capitalize on this normal guitar characteristic to invoke 'panic' and suggest they do repairs on the guitar to fix it before it implodes.

The dangerous sign is a dipping between the bridge and sound hole.

Hope this adds to the conversation and stirs up the critics…

[abn556]

I did a quick search trying to find what the radius is for Eastman tops, but got nothing. The OP could put a straight edge across the top behind the bridge and you should see a little gap on each side if the straight edge is perfectly level.

[KevinH]

Welcome to the forum! Instructions for posting pictures are given here:
https://www.acousticguitarforum.com/...d.php?t=511949

As others have noted some bellying is normal. A picture would help. Or try laying a straightedge across the lower bout behind the bridge and measuring the gap between the straightedge and the guitar top on each side.

Have you had the guitar long enough (maybe a week) for it to adjust to your environment?

[Biosphere]

Are you using medium strings? I find my Eastman dreadnoughts belly if using medium strings, less so with light strings.