Workshop: Archtop/Fretless Bass Conversion

While resetting the neck on this archtop, I decided to do a wild project and convert it into a fretless acoustic bass guitar. After hodge-podging some stuff around the workshop to test out ideas, I felt it was time to "do it right" and make a gigging-useful instrument to replace my "double bass" needs. This is it... and it exceeded my expectations. It can record acoustically (and practice acoustically) but it sounds sweet plugged-in.
My mods: new fretless rosewood board, new nut, headstock alterations for 4 tuners, mandolin-style tailpiece, modified cello bridge to replace an archtop-style bridge, and some new LaBella "Hofner bass" flatwound strings. These have smaller wrappings at the headstock end so guitar-style tuners suffice. They also sound a lot like spongy steel double bass strings: very fundamental. The recording above is "straight in" and the K&K pickup sound has not been altered. Once you put it through a good bass amp you can sculpt it even more.

Pretty slick, huh?

I feel like it was a bit of a sin to convert this, but jeez, I love what my fingers are feeling and my ears are hearing. It'll get its first "gig" tomorrow at a farmer's market.

Don't mind my sloppy string mute. I used an old mandolin tail ("Bell Brand") which had half-round cutouts that perfectly grabbed the string-ends.

I violin-ized the neck on this by making it bare and then sanding, adding two very thin layers of polish, and then buffing-up. It feels like bare wood and now you can see all that gorgeous maple (rather than peeling nitrocellulose crackle).

Bigger pearl dots for 3, 5, 7, 9, 12, 15, 17 and small dots for the rest. I set the scale at 25 1/4" or so. What I've found about getting "double bass" tone out of guitar-sized objects is that it works best to use a shorter scale and light-tension flatwound strings. It gets you that "bum-bum, waaah" sound a lot better than higher-tension, long-scale strings which tend to have more sustain and a more "electric" sound.