Experimental Steel String Top Build

[RGPGuitars]

I am actually surprised at the lesser bass response. The lattice braces are the same size as I usually use, and the longitudinal braces are the same as my x braces. I am GUESSING!! that the lower transverse brace removes some of the vibrating plate from beside the sound hole that produces bass, like a dreadnought . But still, early days yet. I must admit, I enjoy experimenting with design. Can't be right every time. Lol.

[redir]

I think you are right about the lower transverse brace. Somogyi talks about that in one of his books in fact. Then lower brace sort of 'cuts off' that section of the guitar and contains all the modes in the lower bought. That was my understanding of it anyway.

[RGPGuitars]

Thanks for the insightful comments.😊 I will look at Symogi's books on that. Been awhile and I don't recall that at all. Poor memory, ugh.

[OddManOut]

Just a thought...

I wonder about the boxing-in of the bridge plate. The bridge system is vibrating into a enclosed portion of the top. While I know other brace designs do this (e.g. Larrivee's original bracing), I would think that would need to be compensated by some reduction in mass. Perhaps braces with a parabolic cross section or even blades.

Originally Posted by RGPGuitars

Thanks for the insightful comments.😊 I will look at Symogi's books on that. Been awhile and I don't recall that at all. Poor memory, ugh.

[M Hayden]

Jim Williams, an Australian builder, published an article in the GAL journal many years ago about a series of instruments he built using a similar approach. He made an extremely rigid frame for the top and within that had two flying buttress braces above a lattice on the soundboard. They sound qualitatively different from a normal x braced instrument but certainly not bad.

Here’s a video of a younger Aussie builder using a similar approach:
https://youtu.be/ahVkP15LtKE

It’s interesting but it looks complex to execute next to the construction we’ve become used to.

[RGPGuitars]

Smallman lattice bracing was my inspiration to do lattice braced nylon strings, sans the carbon fibre/epoxy, and normal box construction,unlike him as well. Very happy with the results. That was the reason I tried an X brace, lattice brace system for steel strings, and I am VERY happy with them. Seeing Taylor v brace with the lower transverse brace, like classicals, and the fact that classicals are bassey little things, got me thinking and ended up with this design. It is also why I said I was initially surprised at the lower bass response. I should be content with the x/lattice I have been using, but curiosity gets the best of me sometimes. Russ

[OddManOut]

Originally Posted by RGPGuitars

Did not know about stress risers. Thanks for that. Very useful knowledge. Luckily I used round bottom bit to start, then removed the rest of the wood and then soften d the edge with sand paper. A fellow I used to know who grew up in Appalachia said "even a blind pig finds a mushroom now and again. " seems appropriate to me in this instance. LOL. Russ

Just curious about the to thicknesses you're using.

[dekutree64]

I'd like to see some chladni patterns on this. Especially the monopole mode, to see how close the bridge is to the node line.

Bracing patterns with a lower transverse brace work better with a 12 fret neck and/or longer scale and/or higher soundhole (see how classical guitars do it by splitting the last fret around the hole). As redir says, that brace should be considered equivalent to the perimeter.

[printer2]

Classicals are inherently bassy due to the strings from what I understand.

[M Hayden]

Not so much the strings per se as the number of overtones vs steel strings. Nylon has 10-12 overtones while steel can have 60-100 or more....

[RGPGuitars]

The lower transverse brace is definitely the top perimeter of the vibrating plate. It makes sense that the mono pole would be better if the bridge was closer to the centre of the vibrating plate.The top is WRC @.125". The bridge plate is a two piece laminated maple with a total thickness of .080" glued up in a radius dish. The lattice braces are radiused on the bottom. The bridge plate might seem thin but the sustain is excellent.
Thank you all for your insightful comments and questions. Russ Parker

[RGPGuitars]

Well, the sound did improve with playing, especially the mid range. The bass response was still not up to my expectations. the new top is 3A sitka, with very tight annular rings, and lots of medullary rays showing. I know that this new top bracing will be strange to some, but this design has produced my best sounding SS's by far!!! The original top is removed and the new one ready for glue up. Happy I used hide glue. LOL. Russ

[RGPGuitars]

Well, all done with the new top. Quite happy with the results, giving the sound volume and balance I strive for. Not that I needed another lefty SS. LOL.
Think I'll keep the first top around as a reminder. Every mistake is a learning lesson, apparently. HaHa. Russ Parker

[SJ VanSandt]

Thanks for the very interesting and educational thread, Russ. The end results would be beautiful . . . if I could wrap my brain around a pick guard on a lefty. My old calcified brain just won't do it.

[RGPGuitars]

Thanks SJ. Imagine building lefty and righty's regularly with an old calcified brain (me too) and trying to keep things straight, neck dots, saddle slots, pick guards, nuts. Lol.