Trevor Gore on tucking top braces into linings

[Chad Gillander]

My guess is that tucking the braces is common practice because that is what Martin does. Much of what is done stems from looking at quality instruments and emulating techniques that were present in those instruments. Tucking the braces may also prevent the brace ends from popping loose. Not a bad thing in terms of instrument longevity. However, Gilet and Gore are presenting their ideas in an attempt to make the instrument more responsive, or at least give the builder more control over the sonic end result. After all, just because something is historically done a certain way, doesn’t mean that it is the “right” way, whatever that means. Options on a menu.

[Randy Zwitch Zwitch Guitars]

I had wondered this myself, whether it was worth the effort to perfectly notch the linings to make this work. Because frankly, the logic doesn’t really hold up…if the brace were to come unglued, wouldn’t it potentially be rattling inside, even if it were pinned down? 🤔

[Karl Borum – Borum Acoustics]

I just finished a dreadnaught with the lower X braces feathered to zero and it has a very distinct and pleasing voice. I can’t speak from any real engineering or scientific perspective about it- but it feels and “sounds” very different. It’s only the 4th guitar I have built (all dreads) and its Black Walnut back and sides, so I can’t speak for what element had what effect, but I love its voice, tone and resonance. I’m building an OM and will do the same thing- feather the X braces to zero. It definitely didn’t have a negative effect (more resonance, cleaner bottom end). I measure my resonance modes with FFT but I could not see an appreciable difference in the FFT plot of #4 vs the previous three.

[Michael Minton]

I communicated with Trevor, and he said the difference (notched/slotted-in versus tapered to zero at the edge) does show up in monopole mobility testing.

I’ve always notched the X braces, and like how they ensure the correct position of the top (and back) when glued on. I may continue to notch for that reason, but then taper to zero once the top has been glued on.

[Larry Coon Larry Coon Lutherie]

Hanging all replies here —

* Chad, that makes a lot of sense that it came from Martin. How many builders are influenced by Martin, vs. how many were influenced by Trevor Gore? (Especially when it’s one comment buried in one of a big two-book set.)

* Michael, thanks for communicating with Trevor! (I have one other direct connection to Trevor, but I didn’t think about asking that person to ask him.) And yeah, I would expect there would be empirical results visible in the monopole mobility (and possibly SPL), along with intangible results perceived in the sound quality. I’ve always had pretty high monopole mobility, so I wonder what building extra mobility into the top would actually bring me.

* Chad — I hear what you’re saying regarding braces potentially coming loose. Just as with any other risk analysis, it’s always risk vs. benefit. What benefit do I actually receive from doing this, and what risks exist for problems down the line? Weigh the two against each other, and see where the scales fall.

I’m wondering if there’s a solution where you notch the linings and the sides with a deeper notch for the braces, but be very careful to glue only the ends. This would leave some space for the top to vibrate more, while still tucking the braces into the notches to ensure correct alignment as Karl & Michael said. (Doing this may be functionally equivalent to feathering them to zero after gluing — I’d have to think that through.

[Larry Coon Larry Coon Lutherie]

Also, I build instruments in pairs, so I could also try doing this with one and not the other, while keeping the builds pretty consistent otherwise….