Replies to This Discussion

Permalink Reply by Keith Rearick on February 23, 2020 at 7:55am

Maybe if you bought a regular set of strings, it would then sound better. Using weed wacker for stings instead, you don't always get what you want.

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Permalink Reply by Cause the Blue rat on February 23, 2020 at 12:16pm

The thickness of the body plays a big part in how much sound you get. The thicker the wood the less over all sound. Even the sides and back matter. 

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Permalink Reply by Taffy Evans on February 24, 2020 at 4:51pm

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Permalink Reply by Taffy Evans on February 27, 2020 at 8:38am

Another lost post?? It seams above. But maybe fixed now?

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Permalink Reply by Taffy Evans on February 27, 2020 at 12:40pm

Hi, here is my 2nd go at posting here, [and it did not work this time either] although it will be a shorter version
Firstly, I don’t feel that weed Wacker cord has enough mass in them to drive the thick-ish top of your box. Deeper sounding instruments normally have a larger sound box and longer scales. Within a larger box comes more air, your strings must move a thicker top that in turn has to move more air, which carries the sound…. or not.
You will recall that strings are “wound” so as to add that mass, as they go from treble to bass they get heavier.
Two-piece tops and backs are a requirement in well-built acoustic instruments.
The sides do not play a part and are not that important in the sound producing cycle, other than being stiff enough not to rob the top and back of vibrations.
Taff

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Permalink Reply by JD on February 28, 2020 at 6:09am

Thanks for all the replies. I replaced the soundboard with 5mm ply and changed the sound hole cutouts. This improved all the strings but still the G sounds good and the others are progressively duller. I agree that I think the problem is primarily the strings. The strings are nylon with a kevlar core and the manufacturer says they are primarily use for rockabilly slapping. You can see in this video how the low notes don't sustain well even on a genuine upright. Still this guys uses them to great effect.

https://www.youtube.com/watch?v=wghzwSr4T9o

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Permalink Reply by JD on February 28, 2020 at 6:11am

Taffy, what do you mean by "Two-piece tops and backs are a requirement in well-built acoustic instruments."?

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Permalink Reply by JD on February 28, 2020 at 6:17am

Ha, joke is on me. I was just photographing the bass for the gallery and it fell and broke two of the ten inch long tuning pegs.

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Permalink Reply by JD on February 28, 2020 at 6:29am

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Permalink Reply by JD on February 28, 2020 at 6:30am

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Permalink Reply by Taffy Evans on February 28, 2020 at 1:15pm

Hi, in your opening post you mentioned the top was joined by a tongue and groove joint. In case you thought that that may be detrimental, I mentioned that good acoustic instruments have top and back plates joined down their centre.
I only do it on cbgs to get a larger top or back panel.
In case anybody is interested, the reason for “book matching”, slicing a board and opening it like a book and then gluing together has several benefits.
1- The close grain sides of the ½ board faces are glued together. That makes the centre of the top stiffer and stronger. The outside edges are more flexible.
2- There is also a more uniform layout of grain lines that aids in better sound production
3- On the back it allows for the matching of complex grain patterns.
The photos my explain this better.

But.. you don't have to follow the rules, here is a three piece back.

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