Tuesday, February 18th, 2014
Correct sound post placement in basses is very important to maintain structural integrity as well as good tone quality. Last week was the first time I ran into this problem with a bass. This type of problem is common when repairing violins and cellos. The sound post was from another instrument or totally counterfeit.
Carving a new sound post is a lot more expensive than simply resetting it. When shaping the top and bottom, you have to take into account two curves on top as well as the back of the bass. Due to the width of the wood it is not enough to only consider the curve from the center to the treble f-hole. You must also consider the curve from the bridge down to the tailpiece. Else, the sound post will dig into the wood on top and bottom or even break through over time.
Different instruments have different sound post heights; even if only 0.5mm-2.5mm. This can make proper placement impossible without re-cutting and then reshaping the post. The work required is the same as building it from scratch.