Ι have noticed that the back of the double bass's body is cut and glued in the middle:
I first noticed this on some cheap double basses and I thought that it just wasn't good work, but then I saw a couple of really good double basses and they had the cut as well. (But I cannot be sure if this is the case on all of the double basses)
What is the reason the manufacturers do this?
One reason is that it's bookmatched - the grain on one half matches that on the other. Another reason is that it would take a fair old tree to slice a piece of wood that size from it. Another is that the wood isn't exactly flat, so to bend one piece in the middle isn't an easy job. The grain on very expensive instruments is better matched than cheaper ones, which is one reason they're more expensive!
Most modern string instruments even down to violins (where the size of the slab is less of an issue) are. A single slab of wood is cut in two horizontally, and then opened like a book and then glued together. This is done since it is difficult (probably impossible for a bass) to find good single slabs of wood that are big enough for an entire body, but provides uniformity between the two sides of the body (which you couldn't achieve if you just glued two separate pieces together).
Thanks Tim -- "bookmatched" was the word I was just searching for.
