Hybrid X lattice bracing

[GarciaGuitarsOz]

Hi every one this is my first time posting. I've been a member for a little while now and have really enjoyed the discussion topics I have managed to search on and read.

I'm keen to get some advice on bracing a 12 fret OM acoustic. I would like to play with the Somogyi style bracing, Hybrid X lower lattice and was wondering how much of an affect lattice brace angle has on top movement.

The X bracing is 6mm wide, so not super light and sits at 90 degrees.
Due to this, the lower quadrant doesnt have a lot of space.

A double X lattice causes the brace angle to sit at about 140 degrees which is not parallel to the Main X as you would noramlly see but does sit at roughly the same angle as 2 normal lower tone bars.

My intention is to anchor the main tapered parabolic X bracing, top and bottom and to leave the lower quadrant floating.

Should I change to a single X with some extra floating bars to get the right angle or just leave it as it is?
Photo attached, braces not glued in.

Thanks in advance, I look forward to hearing every ones reponses.

[blackalex1952]

Are you letting the lattice ends into the sides? Are you letting the X braces into the sides?
-Ross

[GarciaGuitarsOz]

Hi Ross, thanks for your reply.
The X will be let in to the linings both upper and lower bouts.
The lattice will float freely, not even coupled to the X but will be attached to the bridge plate.

Regards
Remi

[kiwigeo]

My immediate thoughts. How thin is that top? The braces look fairly meaty and my main worry would be ending up with an over braced lower bout. I bought Symogi's books and there are some interesting ideas in same but I've found Trevor Gore's books much better as he explains the theory behind the design so much more completely and backs it up with hard data.

[GarciaGuitarsOz]

Hi Martin, yes I have both sets of books and really love them.
Somogyi doesn't discuss dimensions though I've built what I consider to be some very successful dreadnoughts with standard Martin X bracing using them.

As for lattice dimensions they are currently 10mm high by 6mm wide. Which is some thing that concerns me as well.

My top is evenly thicknessesd to 2.7mm

I had thought to make the lattice 4x8mm slight bigger then what Trevor uses on his classical.
No one in my peer group could provide any feedback on sizing or angles so I've been winging it quite a bit.

[56nortondomy]

Hi Remi. All my ss guitars are x and lattice braced. I use a 120deg angle and the elements are about 2.7mm x 5mm high with 50mm centres and are scalloped. My tops are around 2mm to 2.2mm thick. Like Martin said your braces look fairly big, I'd be thinning them down a bit. The photo is a guitar I'm working on now and has a spruce and WRC top at the owners request. Wayne

[GarciaGuitarsOz]

Hi Wayne,
Thanks for the specific dimensions and the all important brace angle I was after. They sound very similar to what Trevor uses on his Classical guitars from memory.
How does the top hold up to destortion over time? and what kind of top activity are you achieving in simple terms using your method?

The previous 6 Acoustics I built were all standard X brace with two tone bars in the lower quadrant.

I've tried every thing from anchoring every brace to the lining, inspired by Ervin, which produced a powerful and responsive guitar with good note seperation through to the Voicing approach that Kent Everett teaches in his videos with heavy scalloping and a tuned top and back which I found produced a beautiful deep open voice with sparkle or lots of harmonics.

My aim in trying something new is to produce an all rounder as I've heard with some of Ervins guitars which some how play incredibly well as both finger style and simply strumming chords.

If I understand corectly, and please correct me if Im wrong, the lattice will not only help the top to move as one but also in every direction unlike the parallel tone bars which mostly promote tripole activity leaving the cross dipole some what lacking. Further to this I understand that the aforementioned in turn drops out the mid range, by design, just enough for vocalists to fit in to the mix. ( so not with out its place in the grand landscape of building to a customers requirements)

[GarciaGuitarsOz]

Wayne just out of interest are you using carbon firbre under your lattice?
In the photo on the bottom left corner the lattice arm feathers out to nothing. is it a shadow I see or carbon fibre under the braces?

[56nortondomy]

There's CF under the lattice as well Remi. I've built 6 guitars using this bracing including the one I'm working on. They've all turned out to be really good sounding and very loud guitars, I'm getting repeat business from some owners so that's a positive sign. Wayne

[GarciaGuitarsOz]

That's fantastic, do you have any recording I can listen to?

[GarciaGuitarsOz]

Hi Wayne,
I did a search on your user name and found many great videos of your instruments, so no need to drop in a link.
Thanks for your advice I'll deffinately be using it as a guideline.

I guess the CF option can be a back up plan, though I'm keen to do with out it.
My original instinct of 4mm x 8mm high might actually be close to the money.

Any one else have experince with CF free lattice bracing?