Acoustic bass

[Rob Mercure]

Hey,

Has anyone constructed what's now called an "acoustic bass" (I think Guild made the first ones, at least recently)? I've been interested in one for years but have never had the spare cash. I just wonder what the experience was like, how successful, and what body dimensions and scale length were used. As well as type of strings and most any other relevent or interesting detail.

Thanks

Rob

[Donald A. Fortune]

hey Bob -- I made a n acoustic bass not too long ago here and I made the body to dred size specs with the exception of the bracing was a lil bit heaver.
If you want to know more I would be glad to share with you ok??
Peace,
Donald

[Ron Frazier]

Taylor makes one and have done a lot of research on it.
String lingth and body size is important.

Ron

[Mike Kolb]

This is probably a good time to pose a bass question.... one of my "one-of-these-days" projects is a new top for my Tacoma acoustic 4-string bass. It's cracked pretty badly and it'd be good opportunity to change that gawdawful (imho) teardrop-shaped soundhole. The body is huge so finding decent wood was tough. Finally found some good-sized pieces and now have 2 choices: a redwood top from LMI and a bearclaw spruce top from Alaska Specialty Woods.

Anyone have any preferences for one over the other? I'm looking for an "unbright" woody sound, so the redwood comes to mind, but worry about cracking and a tendency to dent easily. Also, want to make the soundhole round.... but wonder if it should be cut in the same general location (bass side) or centered or what?... more importantly, why? Thirdly, the Tacoma currently employs a ladder bracing, and I was wondering if anything can be gained by using a modified X pattern? Anyway, your collective input and thoughts all appreciated.

[Dave Yelverton]

Did a bass many years back which worked fairly well. I took the Gibson J200 outline and scaled it to fit, likewise the braces and top thickness. Worked fairly well except for a quiet E. The problem with a bass is that you need body depth to get the best out of the lower strings. I managed 5" at the tailblock but 6" would have been better, if somewhat unwieldy. I have been thinking about this problem recently and came across this link which revives the Torres idea of the tornavoz:
http://www.hago.org.uk/faqs/contrabass/
Listening to the sound samples suggests that this is a solution albeit one which makes the repairer's job that much more difficult!. Has anyone any experience of making/using a tornavoz?

[Dave Yelverton]

Dug around and found a pic.

Hope that's of some interest.

[Rob Mercure]

Looks quite nice - great work - and this is the one with the missing E response? Hmmm, while I suspect that it would look funky I wonder if you could deepen the body under the upper bout tapering (or maybe even stepping) to more shallow under the lower bout to make it easier to play with the bridge closer to your body? Just a thought and maybe impractical but I've always seen them taper the opposite way - deeper at the lower bout - but I've never seen any explanation that stated that it wouldn't work in an opposite manner.

Rob

[Dave Yelverton]

well..I think having a deeper lower bout is more practical purely because of the greater effect on volume. If I can take a moment to put things into perspective; I made this guitar as an experiment at a time when acoustic basses were relatively rare. I thicknessed the top to 3.2 mm which may have been too much and made the braces pretty chunky. The guitar has lasted but I would be the first to admit that it was a little over-braced. I hesitated to dish the back to a 15' radius as I felt that it looked excessive. As I said, the E was quiet and in disproportion to the other strings. However most acoustic basses tend to rely on pickups and an undersaddle strip dealt with this problem although not as well as more recent pickup systems could have.
If I were to build this again, I would modify it in a number of ways. I would go for a 15' radius back (just look at the basses in mariachi bands to get an idea of what is effective). I would probably use a double top to get more resonance and also lighter bracing. The string tension on a bass is not that high and building EVERYTHING in direct proportion to a six-string is probably not too effective. I used X-bracing and would continue to do so but I would probably heavily scallop the struts on the lower bout and counteract bridge rotation with a JLD! The E string even on the longer scale length does not seem to transmit much energy to the bridge and it might well be worth experimenting with a heavier gauge for that particular string. At the end of the day however, you have to appreciate that the acoustic bass is a compromise instrument. You could make a bass fiddle!