Workshop: Tinkered Fretless Acoustic Bass Guitar

The above soundclip starts "dry" and then repeats with a bit of small reverb added to simulate a slightly larger body resonance. This goofy creature is just me being curious about possibilities again. Despite the 25 3/8" scale (similar to 1960s "pocket" electric basses), it gets the job done.

I yanked the label out of the soundhole but it bore witness to the fact that this is an all-laminate classical guitar with the "Estrada" brand and it even had "Ano 1963" penned in on it. Yes, it's a classical guitar... and it was given to me as it was in the sad state of most classical guitars of this caliber: neck pulled up, frets wonky, bridge pulling up -- the usual.

It's not worth enough to fix properly so it sat collecting dust in the workshop until I cooked up a plan. After bolting the neck to get it at a proper angle, I yanked the frets, filled the slots, leveled the board "enough," touched up the color on the board "enough," and converted it to a tailpiece-load fretless acoustic bass guitar. I love the upright tone spectrum and expressiveness (especially for recording), but can't stand carrying one to gigs -- so I made the executive decision to get rid of mine last year lest people pester me about playing them for shows.

My experience with acoustic bass guitars is that they're all terrible -- after a fashion. My experience with building my various banjo basses is that you can make something tonally pleasant on a small scale and the sound would consistently lean more "upright" the more one shortened the scale and thickened the strings. Obviously, that removes overtone ring, cuts down on sustain, and gives a fat, fundamental front to a plucked note with quick decay. What does that sound like? Yeah, double bass. The only problem is that it's a very quiet sound with a shorter scale/less tension setup so it's only useful for recording or for attaching a pickup (read: K&K) to.

My other complaint with most "ABGs" is that most of them, even fretless ones, stick to a "pin bridge" load on the top rather than a tailpiece load -- the latter is more similar to double bass in the way it engages the top. So... a quick hack-n-patch job and this (ladder-braced, slightly clunky but lightweight) guitar is now run from the tail.

The only reason I can get away with using a classical guitar neck is that, at this scale, even these 100w-bottom D'Addario Chromes don't put much tension on the neck. I don't really like these strings much, by the way -- they're a little too forward and stiff -- but I had them in my spare bits drawer. Now that this is a living, breathing instrument of sorts, I'll probably switch to LaBella flats to get a smoother mwah and fat clunk to the bottom end.

The other benefit of a classical neck is that my left-hand approach is more spread out and, in an odd way, it lets me approach this clunker more like an upright as it's more work to "move over."

The board is gloriously junky! It's actually plywood with a thin layer of rosewood on the top. You can see it's been sanded-through in a few spots during leveling. The filled fret slots are totally non-glorious, but they get the job done. Like I said... cheap guitar, cheap work. My "budget" was an hour and fifteen minutes or so.

I added a downpressure bar (a flipped old adjustable electric saddle) behind the saddle so the strings wouldn't slip with aggressive plucking.

A simple mandolin tail holds the strings just fine.

The classical-style tuners with their enlarged shafts are perfect for wrapping bass strings around. Note the removed shafts.

So, the lesson here is: sometimes dumber is better. This is a terribly "dumb" design but it does what it sets out to do: provide a reasonable "upright" sound that, when put in front of a mic, would be decent enough to fake a cheap upright bass tone.

I don't mind showing ridiculous little experiments like these because I hope they give other folks some ideas for modding on the cheap or turning junk to more-useful junk. Obviously, I didn't care about looks or impressiveness, so it's not pretty. Then again, it was a hideous guitar to begin with...!


Unknown said…
I think it sounds great! I'd gladly buy it off of you!
Amahl_Shukup said…
Practical and workable doesn't have to be pretty. Interesting job, Jake. I wonder how long those plastic cylinder parts of the tuning machines will last under tension; they look fragile when you see those bass strings on them.
Jake Wildwood said…
Classical guitar tuners are usually a brass shaft with a plastic outer. They'll be just fine. :)

Taylor: I'll make another one and let you know. I have no end of funky classicals around here...
Unknown said…
You could also put a few coats of lacquer or epoxy on the board to make it really muwaaaahhhhh
Unknown said…
This actually sounds better than the Kala U-Basses that start around $450 and go up to $1400.
Jake Wildwood said…
Yeah, and it's actually a lot louder acoustically. You can definitely sit around playing one of these to practice bass progressions. I was never that impressed with the U-Basses because the strings are so awful and the tiny board makes clean playing difficult.

Even the new Aquila strings (a huge improvement) don't quite do it. It's too rubbery a sound... and the strings on here right now aren't very good, either (Chromes are fine on electrics but sound like cheap student double bass strings acoustically).