Acoustic Guitar Construction

Hi there! I am new here, so I hope this is the right place for this post.

My first guitar that I bought which I really fell in love with was a breedlove back in 2006. I have seen in various images/videos over the years a plate that they put from the Upper Transverse Brace all the way thru the neck joint, which is glued onto the soundboard. In the video I've linked (at 9:52), they call it a "Henderson Plate" -- probably after Steve Henderson. Anyway, it's like an upside down trapezoid, to support the joint of the fretboard to the soundboard I guess. But I've only ever seen this design in breedloves.



The video also shows how they cut a mortise in the sides where the top joins the sides, in order to accommodate the plate. Which is really interesting to me.

Have you guys seen it elsewhere? How does it help the design and tone of the guitar, and how does it compare to other designs (such as an A brace connecting to the neck block)? I would appreciate all your thoughts, as this is just something I've always wondered about.

https://youtu.be/g5fC6a7WFCM?t=592

- Colby

Looks like a pain with all of that fitting required, being on the heel side of the UTB I suspect it does nothing for sound. I put a plate in that butts against the heel block and the UTB. If one thinks about it, the heel block is 90 - 95 mm tall, what would a swap of 2 mm of mahogany for what ever the plate wood is under the block do that would change the structure or the sound. I always considered the plate crack control from the tension of the neck. There are some features that luthiers put in to demonstrate craft.

Having said that. I do like the rest of the bracing and think it is a great example of how to brace a steel string.

John Parchem wrote: ↑Tue Apr 05, 2022 11:54 am There are some features that luthiers put in to demonstrate craft.

Your last comment was interesting. So do you believe they just add that as a feature to demonstrate the craft of their guitars? I always thought it was for support where the fretboard glues down on the soundboard -- which sorta makes sense in theory. But I'm new to lutherie, so I'm just speculating. I would think that your thoughts are much more accurate.

CMStewart wrote: ↑Tue Apr 05, 2022 8:12 pm

John Parchem wrote: ↑Tue Apr 05, 2022 11:54 am There are some features that luthiers put in to demonstrate craft.

Your last comment was interesting. So do you believe they just add that as a feature to demonstrate the craft of their guitars? I always thought it was for support where the fretboard glues down on the soundboard -- which sorta makes sense in theory. But I'm new to lutherie, so I'm just speculating. I would think that your thoughts are much more accurate.

The plate is a good idea, But " cutting a mortise in the sides where the top joins the sides, in order to accommodate the plate" was not necessary. The fretboard lays on the heel block so there is no need to reinforce that area. The plate or a popsicle brace should be between the heel block and the Upper transverse brace to prevent cracks.

I have a couple of questions about the bracing shown in the photo.
Are both lower legs of the X scalloped, or just the 'treble' side?
Why only the one finger brace on the bass side?
Are the upper X arms shaped differently from one another?

Sorry, but to me it is laborious nonsense.
There are lots of guitars with just a popsicle brace, or without, or with an A frame.
They all can work and sound just fine.
Herman

IMO, there is no bass or treble side of the guitar top. If the bridge is glued properly, all the strings are coupled to the entire top.

Dave Bagwill wrote: ↑Tue Apr 05, 2022 10:41 pm I have a couple of questions about the bracing shown in the photo.
Are both lower legs of the X scalloped, or just the 'treble' side?
Why only the one finger brace on the bass side?
Are the upper X arms shaped differently from one another?

Hey Dave, see the photo below. That should give you another view and kind of answer your questions about the bracing on this model. It's a different piece, but for the same model.



I have heard some say (as Herman expressed) that there is no actual "bass" or "treble" side to the top. I think I agree in the sense of a strict line between them. But intuitively, I think there are some differences, based on where the string attaches, and the area of the guitar it affects the most. Just like with a tsunami in the ocean, if one island is 100 miles to the east, but there's another island 200 miles to the west... the affect on those two will be somewhat different. Especially if you account for different barriers in between the two (bracing in this case). When voicing a top, you get to play with that. But in general, all the strings are going to affect all the top to a great extent, but there still are differences.

This is just my intuitive sense, and completely non-scientific. I've discussed it with many people in the past and I know some strongly disagree. It's just my 0.02.