Posted by Greg Turner on August 24, 2020 at 11:02pm
On the right is the guitar body which holds up the instrument at the correct angle without the use of a footstool. How do you think the increased size and asymmetrical nature of the instrument affect the sound? How would the bracing work on something like this? Any other considerations?
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Hey Order 99. The soundboard is flat 1/8th inch panneling which is laminated. No bass bar planned. Sound post yes on the gamba. I plan to use an "I" brace on my gamba but the old department store bracing system ala cheap guitars on my guitar build. It calls for a bridge plate. I like your schemes too. Very sensible.
So....what type of wood is your instrument soundboard made of (Mahogany,spruce, basswood, laminate? How thick will the material be? Will the soundboard be flat or arched? Do you want a bass bar to dampen the base and equalize the treble like a violin? Will you use a sound post to support the top and add vibration in the back(again, like Violin)? All of these questions will modify the pattern...
Even in thin plywood boxes I have started to add an inverted 'T' micro-brace of 1/4 inch tapering to 1/16 inch-seems to make the sound a little richer somehow.
If i'm lucky enough to find an actual thin wooden box (usually cedar) i'll use an 'A' brace of 1/2 inch tapering to 1/8 inch and touching the sides, and glue a 1/16 inch veneer where I want my sound holes (especially the 'f' and 's' holes.
Nearly all my builds use a tailpiece-if perchance I use a fixed bridge I will add a bridge plate.
Overkill? maybe-but I lost a 'quality' (not worth the $80.00) store-bought uke lately due to both a dearth of proper bracing and a bridge plate of less than 1/4 inch. At least it has a great neck tuners and nut, so expect to see a San Dona Cigar Uke later on...braced.
All very thoughtful responses Bernie. I was looking more for a generalized approach though becaue I'm only currently thinking of a prototype. Hoping for a bracing structure which at least helps the sound a bit instead of hinders it a lot. I found the "department store guitar bracing" had become the defining sound of country and blues recording in their heyday cause that's all most people could afford. Later it became preferred for a down home sound and is even enjoying a resurgence. For cigar and winebox guitars with hardware store pannel tops, complex bracing don't make a lot of sense but I think a minimal bracing scheme does. I'll post a pic of that hardware store bracing scheme. Anyway, was still wondering how you thought having that extra bit of top would generally affect the tone.
Forgot to say that you would ideally do this across a range of audio frequencies and the sound bars would then be placed to support the pattern/blend of patterns you choose.
Ideally you need to establish the soundboard's noadal resonance profile. This would normally be done using special electronic equipment. However you might be able to get a good idea by treating it as a 'Chladni Plate' before fitting, maybe by fixing one edge in a vice and using a violin bow to excite it. A thin layer of 'silver?' sand on it would then show the nodal pattern.
Once you have established the nodal pattern then you can arrange the sound bars accordingly...I think I am right in saying these should be the areas that are NOT nodes? I am sure somebody on here will be able to correct me.
This looks an interesting musical instrument technology project!
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Hey Order 99. The soundboard is flat 1/8th inch panneling which is laminated. No bass bar planned. Sound post yes on the gamba. I plan to use an "I" brace on my gamba but the old department store bracing system ala cheap guitars on my guitar build. It calls for a bridge plate. I like your schemes too. Very sensible.
So....what type of wood is your instrument soundboard made of (Mahogany,spruce, basswood, laminate? How thick will the material be? Will the soundboard be flat or arched? Do you want a bass bar to dampen the base and equalize the treble like a violin? Will you use a sound post to support the top and add vibration in the back(again, like Violin)? All of these questions will modify the pattern...
Even in thin plywood boxes I have started to add an inverted 'T' micro-brace of 1/4 inch tapering to 1/16 inch-seems to make the sound a little richer somehow.
If i'm lucky enough to find an actual thin wooden box (usually cedar) i'll use an 'A' brace of 1/2 inch tapering to 1/8 inch and touching the sides, and glue a 1/16 inch veneer where I want my sound holes (especially the 'f' and 's' holes.
Nearly all my builds use a tailpiece-if perchance I use a fixed bridge I will add a bridge plate.
Overkill? maybe-but I lost a 'quality' (not worth the $80.00) store-bought uke lately due to both a dearth of proper bracing and a bridge plate of less than 1/4 inch. At least it has a great neck tuners and nut, so expect to see a San Dona Cigar Uke later on...braced.
Forgot to say that you would ideally do this across a range of audio frequencies and the sound bars would then be placed to support the pattern/blend of patterns you choose.
...correction to first line...'nodal'...apologies
Ideally you need to establish the soundboard's noadal resonance profile. This would normally be done using special electronic equipment. However you might be able to get a good idea by treating it as a 'Chladni Plate' before fitting, maybe by fixing one edge in a vice and using a violin bow to excite it. A thin layer of 'silver?' sand on it would then show the nodal pattern.
These pages might be useful? https://www.instructables.com/id/Easy-Chladni-Plate/
Once you have established the nodal pattern then you can arrange the sound bars accordingly...I think I am right in saying these should be the areas that are NOT nodes? I am sure somebody on here will be able to correct me.
This looks an interesting musical instrument technology project!