Monday, July 14, 2008

7-String Bass/Baritone Mod

Sometime last month I found that Rondo Music was selling six string long scale bass guitars for cheap. Even though I knew they were probably made in Chinese sweat shops by people with between seven and nine fingers I bought one. I swiped this picture from Rondo's web site, but this really is what it looked like when I took it out of the box.
Let me be specific about what "long scale" means when you are talking about a bass guitar. On a long scale bass the scale (the part of the string that vibrates--everything between the bridge and nut) is about 34 inches. Compared to a standard electric guitar this is really large. It is almost a foot longer than a Gibson Melody Maker and more than a foot longer than John Lennon's Rickenbacker 325. It is almost ten inches longer than the scale of a Gibson Les Paul or SG and eight inches longer than the relatively generous scale of a Fender Stratocaster or Telecaster.

Why does this matter? It's a bass. Larger instruments make lower sounds, right?

Yes, basically, but there is more going on here. String tension and weight also play big parts in pitch. Each also impacts sound and playability. Longer scale, more tension and heavier strings increase sustain and make for a "bigger" sound, even for higher notes. In fact, may people think it just sounds better. It certainly feels different to play instruments of different scales.

Which is why the six string bass I bought from Rondo is no longer a bass and now looks like this.

The original idea was to add multiple strings, shorten the neck and make it into an alto tapping instrument. This is what I've been kind of fixated on since I became interested in two handed tapping/touchstyle playing last year. Then something happened. I received and started playing my new bass.

It was fun. I had never played a six string bass for more than a couple of minutes before. With the 34" scale and generous cutaways I had a whopping 24 usable frets. That's two whole octaves! Since the neck was nice and wide (over 2" at the nut) I could slap, pop and snap without hitting extra strings.

For any non-musicians who are still with me, all you need to know is you can't do these things on a standard guitar. The neck is too small.

Sadly, I am not a bass player. Let me take this one step farther. I don't know from bass.

I would like to understand bass I have no desire to be a bass player. This is where my desire to have an alto touch instrument came from. Most touchstyle instruments are aimed at people who want to play bass lines while doing other stuff in the guitar register.

What I purchased was not only a bass, it is a step or two beyond the standard four-string bass. Like other five and six string basses the low string is a fourth (the equivalent of five frets) lower than that of a four-string bass. One way to look at it is that three of the six strings on this instrument are dedicated to notes I didn't want to play.

Within a few days of this beautiful green beast arriving at my home I had pulled off the lowest strings and moved the others to the left. I bought the thinnest bass strings I could find and tried tuning the whole instrument higher--into a range I more or less understand. It wasn't enough. To get the whole instrument into the register I wanted to play in I needed to fit it with at least one guitar string.

It turns out that bass tuners and guitar strings are incompatible. This is where I knew I was going to need to reach for my drill, and quite possibly, a saw. That was all part of the plan from the start, but now the goal was different. Now I wanted an instrument with a great huge neck and a monster long scale that I could use my guitar skills with.

What I settled on was adding a seventh string and tuning it like a seven-string guitar but down a fifth. ADGCFAD This makes it a bass-sized baritone guitar.

Here is what I ended up doing to the head. To accommodate guitar strings I installed two guitar tuners as close to the nut as I could. They grip skinny, slippery guitar strings properly and I was able to save some space.

Here you can see how the string spacing ended up. I knew I should make a new nut anyway, so I went ahead and eyeballed the new notches I put in this one. Not brilliant, but acceptable for a first draft and surprisingly playable.

The other problem with guitar strings is that the metal balls on the bridge end are too small. This bass has a "string through" bridge and body. This means that the strings actually pass through the body of the instrument before going over the bridge and up the neck. The holes in the body are too big and the ball on the end of a guitar string will pull right through.

To make room for the two guitar strings at the other end of the scale I did two things with the bridge. I moved it to the left a little bit and removed the right-most saddle. The saddle itself was just held in place with a little allen bolt but I had to cut the rest of the section off with a hack-saw. This was to make room for the two guitar saddles I cut off of a Telecaster-style bridge. I also had to grind the back of the bridge down to make room for the intonation screws behind the guitar saddles.

The big gouge in the wood between the bridge and the knobs is from me loosing control of my RotoZip grinder while working on the bridge.

I love this beast. My Telecaster feels tiny now, but this baritone animal does tricks my Tele can only dream of. I hope to post some sound samples later.

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