THE SOUND POST

The post is sometimes mystified a bit. Some luthiers like to create the illusion that a subtle, yet masterful adjustment can transform an instrument. I am very skeptical about that. I feel it is rare that any one single thing can have a profound effect on a bass. Except accidents - they can transform a bass pretty quickly. That's what I want to address here - the issue of damage which can occur through improper sound post adjustment.

This is not meant to be a complete tutorial on the post, so I'm only going to cover a few basics. Classically, the sound post on a bass should stand at a 90 degree angle to the flat plane on the instrument [this can be seen as the plane of the glue joint between the top and ribs]. Generally, this is the same angle as the interior blocks and the back of the bridge. This can vary somewhat due to differences in construction. The post should sit centered to the treble foot and about 12-15 mm back from it. This is often the best spot for the post, but a luthier should be prepared to adjust it according to the players taste. The post should wedge in place with just enough tension that it stands without falling as the instrument is rotated.

Much has been said about the dangers of a tight post - mainly that it can lead to the feared sound post crack. I would counter that the danger would come more from ill-fitting posts - not from tight ones. Of course, I am not advocating tight posts, but think about this-if you fit a post perfectly and then brought it up to tension - how tight would the post be? Well, if you cut a hole in the c-bout big enough for your arm to pass through [hypothetical situation - don't try this at home kids!] you could grab the post - lift the bass and rotate it without the post moving. That's tight. Yet a well-fit post does not damage the top plate under normal conditions.

If you took a well-fit post and then changed its angle by only 2 degrees it would then be standing "en pointe." The edges [sharp edges] of the ends of the post would be making contact with the top and back under all that pressure. At best, a dent in the plates result, cumulatively a hole or crack will result. It is rare to find basses not damaged in this way.

I find post fitting to be pound for pound as difficult as scroll grafting. Other luthiers whom I respect agree with this. It takes me about an hour to accurately fit a post. If someone fits a post in 5 minutes they are either an unbelievable genius or a charlatan. I've seen posts "fit" in 5 minutes. Accidents waiting to happen. Final fitting of the post is an extremely fine process. The accepted tool for this is a well-sharpened knife or chisel. Beware if you see someone fit a post with a gross tool like a diskgrinder. What exactly do I mean by "beware?" Any luthier with reason to be proud of his/her work should invite the player to look inside the bass and call attention to all works performed. If this is not done, one might ask themselves why. I don't expect every player to totally understand all the workings of their bass, but I do expect them to at least be visually familiar with it and its insides. I recommend to every player that they possess a mirror and a light for that purpose. A simple inspection mirror can be purchased in an auto parts store and a small halogen flashlight can work nicely. If you have your post adjusted - examine it. You should not see any gaps.

page | 1 |