Question on Acoustic Bass plans and Bass/Baritone dual duty guitar shape?

[emmsone]

Hi all

Due to how well my previous guitar came out, it looks like I may have a commission to build an acoustic bass. What i'm finding (or not finding) so far is that acoustic bass guitar plans are few and far between. I've found 1 good set of plans so far, (georgia luthier supply) but its a 12 fret neck joint design and I know the guy who may be commissioning the build plays ALL over his fretboard on his electric bass so a 12 fret design, even with the cutaway, may not be ideal. Have any of you built acoustic basses? and if so do any of you have the plans you'd be willing to share/sell me?

Second part - If I end up not finding a set of plans to work from and the guy is still interested in letting me build one but with a design straight out of my head, where do I start with bracing? I could possibly borrow from the 12 fret design plans, but i'd probably need to modify it to move the neck joint to the 14/15th fret as per 'usual' (going on the other designs you see around), there is a chance this may not be as big a deal as it could be because the plans are for a 32" scale, if I put a 34" scale neck on it and kept the bridge location the same, i think i'd easily get the 2-3 frets of shift required, but as i'm writing this it's just 'semi-educated' guesswork.

Thirdly - I've recently played a baritone and fell in love with its sound and voice, I had said to myself that if i wanted a baritone, i'd be unlikely to build it mostly because i'm also struggling to find plans anywhere for baritone guitars.
What i'm wondering is, if I have to make a new mould for a big guitar thats big enough to be a bass, i'm thinking if the shape is right (i'm thinking jumbo-ish), I may be able to use it for a baritone build too, but obviously the bracing on both soundboard and back would be different and perhaps the baritone would be slightly less deep, but my initial thoughts are that hopefully I could perhaps use the mould for the sides for both designs and then I wouldn't need yet another mould, does this sound sensible to anyone else??

Thanks in advance for your help

David

[dekutree64]

I'd say 17" lower bout, 21" length jumbo size would be good. But if the baritone you liked was smaller, then copy it, and make a different (and larger) shape for the bass, like 18" lower bout, 24" length.

Adapting the basic X bracing pattern to different configurations is relatively straightforward. The bridge location is based off the scale length and joining fret. Soundhole goes somewhere in the vicinity of the waist, usually a bit above. You can fiddle it around a bit depending on how many frets you want.

Once you have those reference points set, put the upper transverse brace just above the soundhole, upper X legs fairly close to it, and make the lower X legs cross under the lower corners of the bridge. Then lay out the rest of the braces in relatively evenly distributed positions.

For the acoustic bass guitar, definitely put a pickup in it. I've never played a hand built one, but AFAIK they're still pretty quiet even at the 18" wide, 24" long, 6" deep size. I really want to try building one sometime and see if I can get comparable volume to plucking a double bass, which seems to be enough for live acoustic groups. I don't think the typically available acoustic bass guitar strings are heavy enough or long enough for it. And to properly utilize high tension strings, I may have to make it big enough that it's only playable in upright position.

[emmsone]

Having looked into it further, both Baritones I've played, the Furch one, and the Taylor 8 string one (which I liked but not the 8stringness) are both 16-1/4" lower bout, which is definitely on the "smaller" but more "typical" side for most of the baritones. This actually surprised me, I definitely thought the Furch in particular would have been wider, closer to 17" but it wasn't.

It also seems most of the acoustic basses do have lower bouts in the 17" and wider region going up to as big as you like!!! This is leading me to think that it probably is possible to do both on one shape, but it'll be a slightly wider then 'normal' baritone and a slightly narrower bass.

One another point, I did the calculation and moving from 32" scale to 34" scale moves the neck join almost perfectly from the 12th fret to the 13th fret. So not really as much of a gain as I thought it would be.

Thanks for the info on the bracing, that will be very useful if it comes to creating my own 'design'.

Yep I absolutely would be putting a pickup in the acoustic bass, and i've already been thinking of that and i'd be leaning towards something like the LR Baggs Anthem SL.

David

[martinedwards]

For an acoustic bass to have any serious resonance it needs to be a lot bigger than any commercial bass guitar you've ever seen.

Those crazy big things you see in mariachi bands are about as small as will realistically work acoustically.

A pickup is a must if you want it to be heard, even in a very small group