JLT's "Tenor Acoustic Bass"
Posted: Sun May 11, 2014 5:01 pm
Yeah, that's an oxymoron, but I can't think of anything else to call it. The prototype is a converted home-made Dreadnaught, with a 25-1/2" scale length. The idea came from this page:
http://www.instructables.com/id/Acousti ... onversion/
I'd been thinking about building an acoustic bass anyway, and talked it over with a friend of mine who's a professional luthier named Arnie Gamble. He said that it would be better to use a pin bridge rather than a tailpiece, so that's what I did. I removed the bridge, back, and bridge plate. Then I made a new bridge plate that was about 50% thicker and 20% larger in area than the old one (which, curiously, was made of plywood). Arnie slotted a new blank bridge for a 3/32" saddle and I bored the four holes for the strings. Since I had the back off anyway, and I knew that a box that small wouldn't give me much volume, I put a couple of piezo pickups on in case I ever used the instrument in a jam.
As for the tuning, I realized that with the short scale, a conventional set of acoustic bass strings would have far too low a tension for efficient sound production. But If I tuned the strings up a fourth (i.e., five frets) to A-D-G-C, that would give me the same tension as if the strings were on a conventional 34" scale length but capoed up five frets. (The tension, by the way, is about 210#, which is about a third greater than a standard guitar ... hence the reinforced bridge plate.) Hence the "tenor bass" designation. Since the string tension is higher than on conventional tuners, I bought a set of electric bass tuners. It also occurred to me that if I used a really, really thick string for the lowest string, I could use the other strings and get a conventional E-A-D-G tuning, but it seems that nobody makes a string that thick.
The result of all this will be a small acoustic bass that would fit into a dreadnaught case, and that might actually be loud enough for small group jams.
The reason that there aren't any pictures yet is because I haven't finished it. The reason I haven't finished it is that, before I close the box, you all might have something to add that I wish I'd known about before I closed the box. Your comments are welcome!
http://www.instructables.com/id/Acousti ... onversion/
I'd been thinking about building an acoustic bass anyway, and talked it over with a friend of mine who's a professional luthier named Arnie Gamble. He said that it would be better to use a pin bridge rather than a tailpiece, so that's what I did. I removed the bridge, back, and bridge plate. Then I made a new bridge plate that was about 50% thicker and 20% larger in area than the old one (which, curiously, was made of plywood). Arnie slotted a new blank bridge for a 3/32" saddle and I bored the four holes for the strings. Since I had the back off anyway, and I knew that a box that small wouldn't give me much volume, I put a couple of piezo pickups on in case I ever used the instrument in a jam.
As for the tuning, I realized that with the short scale, a conventional set of acoustic bass strings would have far too low a tension for efficient sound production. But If I tuned the strings up a fourth (i.e., five frets) to A-D-G-C, that would give me the same tension as if the strings were on a conventional 34" scale length but capoed up five frets. (The tension, by the way, is about 210#, which is about a third greater than a standard guitar ... hence the reinforced bridge plate.) Hence the "tenor bass" designation. Since the string tension is higher than on conventional tuners, I bought a set of electric bass tuners. It also occurred to me that if I used a really, really thick string for the lowest string, I could use the other strings and get a conventional E-A-D-G tuning, but it seems that nobody makes a string that thick.
The result of all this will be a small acoustic bass that would fit into a dreadnaught case, and that might actually be loud enough for small group jams.
The reason that there aren't any pictures yet is because I haven't finished it. The reason I haven't finished it is that, before I close the box, you all might have something to add that I wish I'd known about before I closed the box. Your comments are welcome!