Double Bass How NOT to convert a flatback.

[Artie Langston]

I thought I'd post a couple of pictures just for general interest. Since about 1984 this old German bass has been my favorite gig and orchestra bass. It has a very nicely carved round back, but it seemed obvious that it had been cut down, as the endpin was not even close to being centered. There were also missing linings, and bits of linings left elsewhere.

One day, after all this time, the lower back seam popped, and revealed at least a 1/2 inch gap!

Apparently, it was originally a flatback, and all was well with the conversion until half way down the lower bouts, where the width was not the same, and even somewhat asymmetrical. It appears whoever did this solved the issue, by just gluing up the bottom seam good and tight. Sloppy, but it probably worked for over 50 years.

So now, we are finally fixing the errors. The back actually fits beautifully as if it were made for the bass.

 

[Matt Liebenau]

Very cool. It is, however in the Bass Guitar side, which I’m good with. I find these repairs fascinating as I don’t get to work on acoustics much. However, I’m guessing it’s not what you meant to do.

 

[Artie Langston]

Yikes! Apparently, the bass is not the only thing that's getting a bit long in years!!!

 

[turf3]

So if I understand, the edge of the ribs all round where the back attaches, was not alll in a plane, which implies whoever built the thing in the first place just bent the flat back to mate up (which wouldn't be that hard - it's thin flat wood), but the round back which is way stiffer had to be flexed HARD to mate up. And then when that heavy duty seam DID finally open, it did so with a bang.

It looks like you're adding rib height, of varying amounts, to make that rim all co-planar?

 

[Eric Hochberg]

Apparently, it was originally a flatback

How did you conclude it was originally a flatback?

 

[Artie Langston]

It looks like you're adding rib height, of varying amounts, to make that rim all co-planar?

Yes. Also, the linings that were cut away are being restored.

 

[Artie Langston]

How did you conclude it was originally a flatback?

By measuring a typical Mittenwald flatback, and the position of the endpin. There are also bits of the original lining. It's quite obvious it was not a giant bass that was cut down, but that the ribs were cut down to where the top of a flatback slope would be at the button.

It seems rather obvious and self evident.