I just shaved my own braces

[wrench68]

Since you are willing to experiment a little in the search for low end, here is something I did to a couple of small body guitars: make a tube the same diameter as the sound hole and about three inches long. Make it from manilla folder material or similar. Drop it in the hole flush with the top, and tape it in place.

You may be stunned at the result. I did this a number of times, and somewhere between 2-5/8 inches long and 3 inches long is the sweet spot where the bass gets big without compromising higher pitches. I find that the smallest bodies work best to the longer length, and as the bodies get larger, shorter works better.

No risk here. If you don't like the result, just rip it back out with no permanent changes to the guitar.

[Roccorobb]

Originally Posted by wrench68

Since you are willing to experiment a little in the search for low end, here is something I did to a couple of small body guitars: make a tube the same diameter as the sound hole and about three inches long. Make it from manilla folder material or similar. Drop it in the hole flush with the top, and tape it in place.



You may be stunned at the result. I did this a number of times, and somewhere between 2-5/8 inches long and 3 inches long is the sweet spot where the bass gets big without compromising higher pitches. I find that the smallest bodies work best to the longer length, and as the bodies get larger, shorter works better.



No risk here. If you don't like the result, just rip it back out with no permanent changes to the guitar.

I read or watched something about a construction method like this from a guitar in the 1920s, but it was a permanent part of the instrument. I'll try it!

[Alan Carruth]

Trevor Gore suggests a test for top stability and tone: the bridge should rotate forward about 2 degrees under string tension. If it's much less than that you could lighten up on the top a bit, and if it's much more it's probably not stiff enough to hold up over the long term. Wood 'cold creeps' under a sustained stress, so the deflection you see initially will tend to be much less than it will be when things have had a few years to settle in. Guidance in wood aircraft structures from the FAA suggests that long-term deflection could be about three times the initial short-term value. Certainly a bridge that has rotated forward by six degrees would be more likely to pull up, if only because of the increased load on the glue line at the back edge.


Sometimes the best way to improve the bass it to shave back braces. The more closely the 'main top' and 'main back' tap tones agree in pitch the more they will work together to pump air through the hole at low frequencies. Usually it's best to have the back a semitone or a bit more higher in pitch than the top: too close and you can get some really nasty 'wolf' notes. To find these pitches you have to cover the sound hole, then tap on the bridge on the top, and in the middle of the lower bout (more or less) on the back.

It's easy to experiment with this. Get some poster adhesive and stick a wad on the back on the spot you needed to tap it to get the clearest tap tone. The added mass drops the pitch; the same effect you'd get from cutting a brace down. It's easier and less destructive to add or take off mass than it is to shave braces. When you get the sound you want you can check the tap tone, and that gives you a target to go for when shaving braces. Within reason shaving back braces is a lot safer structurally than doing top braces.

[JLS]

https://www.amazon.com/Stanley-21-11.../dp/B00002X1ZH

I've always used these, oftentimes just the blade, to shave braces.

[Carey]

One thing about shaving down back braces is that it can be overdone even without getting the back down to the target frequency, in my experience. This manifests in feel as the player not having anything to "push against", when playing with a firm attack. A possible oversimplification, and my experience is limited to nylon strings.

[Roccorobb]

Originally Posted by JLS

https://www.amazon.com/Stanley-21-11.../dp/B00002X1ZH



I've always used these, oftentimes just the blade, to shave braces.

That's exactly what I used!

[Roccorobb]

Originally Posted by Alan Carruth

Trevor Gore suggests a test for top stability and tone: the bridge should rotate forward about 2 degrees under string tension. If it's much less than that you could lighten up on the top a bit, and if it's much more it's probably not stiff enough to hold up over the long term. Wood 'cold creeps' under a sustained stress, so the deflection you see initially will tend to be much less than it will be when things have had a few years to settle in. Guidance in wood aircraft structures from the FAA suggests that long-term deflection could be about three times the initial short-term value. Certainly a bridge that has rotated forward by six degrees would be more likely to pull up, if only because of the increased load on the glue line at the back edge.





Sometimes the best way to improve the bass it to shave back braces. The more closely the 'main top' and 'main back' tap tones agree in pitch the more they will work together to pump air through the hole at low frequencies. Usually it's best to have the back a semitone or a bit more higher in pitch than the top: too close and you can get some really nasty 'wolf' notes. To find these pitches you have to cover the sound hole, then tap on the bridge on the top, and in the middle of the lower bout (more or less) on the back.



It's easy to experiment with this. Get some poster adhesive and stick a wad on the back on the spot you needed to tap it to get the clearest tap tone. The added mass drops the pitch; the same effect you'd get from cutting a brace down. It's easier and less destructive to add or take off mass than it is to shave braces. When you get the sound you want you can check the tap tone, and that gives you a target to go for when shaving braces. Within reason shaving back braces is a lot safer structurally than doing top braces.

Interesting. Great ideas here for lowering the resonant frequency of the box. I may have to take a shot at those back braces

[nuhobby]

That's pretty interesting!

I had a Guild DV52 about 30 years ago. I did some clumsy brace shaving, trying to make it sound more like a (scalloped) Hummingbird I had at the time. I don't think much changed, but I think the whole thing (every piece) was built pretty thickly.

I'm glad you've had some enjoyment.

Chris

[kevd]

Here is a video on scalloping. He says 2-6 months before you start to notice the differences. So keep checking for changes

https://www.youtube.com/watch?v=FaGH7WpkOX8&t=98s