Double Bass Sound Post Pad

[Chasarms]

I noticed that my new Shen has a wooden disk glued to the back to serve as a pad on which the post rests.

My Engelhardt did not have one.

I can see how it might assist in preventing the post from popping through the back, but it also makes sense that it would diffuse and otherwise impede the post's ability to transfer sound energy into the back.

Is this pad the exception or the norm?

Am I correct in assuming these pads are limited to plywood basses?

Do any of our fine resident builders use them?

 

[Bob Branstetter]

It's pretty common on plywood basses. As far as I know, all the old Kays had them. The old HN White King basses had a rectangular one. A tightly fitted post can exert a lot of pressure over a very small surface area - especially if you happen to take a hard hit to the bridge. I've never seen one in a carved bass, but I have seen a few backs that were deliberately carved with a platform for the post to sit on. However, I don't seen any real necessity for having one on a carved bass.

 

[olivier]

Good point: I was thinking about this device when the Eberle/Musima thread started to grow. Most of the Musima I've seen have this soundpost bump in the back, and conversely the corresponding amount of table collapse.

Wouldn't it be wise to include the installation of such a sound-post disk in the first setup of ply basses?

 

[John Sprague]

Alright, who gave Chas the flashlight?
Charles I read your review, and I'm glad you're enjoying your new instrument.

You're absolutely right in that it keeps the post from creating a big old lump. We are currently prototyping a couple of different designs with larger patches. A significant difference between a plywood bass and a carved is that the plywood has a consistant thickness while carved tops and backs are graduated. The graduations (changes in thickess here and there) are a major contributor to the tone of the instrument, and the exact nature of proper graduations is a topic that luthiers argue about ad infinitum. We have been experimenting with different size patches on tops and backs to see how much impact they'll have. More news to come, if it works.

 

[Chasarms]

Originally posted by John Sprague
Alright, who gave Chas the flashlight?
Charles I read your review, and I'm glad you're enjoying your new instrument.

Thanks for the comments on the review. I hope to add something a little more articulate once I spend some more time with the bass. Right now, I don't really know what I know about it if that makes any sense.

Monday is the first lesson since it arrived. I am looking forward to the comments that come from my teacher.

I did spend some time with a flashlight. I just can't help myself. It was a simply a poor substitute for actually messing with something on the bass. Nick has it going along just fine, so I don't think I should tinker. Restraint is hard to come by, but I am finding it.

I must be finally settling down in my old age. My Modulus is the first BG I have ever owned that I haven't found occasion to completely disassemble.

It's in my nature. I did the same thing with every bicycle and the first two cars I ever owned.