Shen Willow flatback bulge

**Adrian Cho** · #1 11-20-2006, 02:33 AM

I noticed sometime ago that my Shen flatback has a bulge in the back. I've never noticed this with any other flatbacks. It seems to be by design and I assume is to prevent the back bowing inward when it gets really dry. Can anybody confirm this?

shwashwa · #2 11-20-2006, 06:27 AM

Quote:

Originally Posted by Adrian Cho

I noticed sometime ago that my Shen flatback has a bulge in the back. I've never noticed this with any other flatbacks. It seems to be by design and I assume is to prevent the back bowing inward when it gets really dry. Can anybody confirm this?

i dont know anything about the shen basses, but i just saw on the site where they mention that the back of the 7/8 willow is "slightly arched over the ribs with an arched X brace."
dont know if that's what you're seeing or not.

John Sprague · #3 11-20-2006, 07:12 AM

Yep, that's it. There is an arch to the x-brace to give it more structural strength. Since willow is a soft wood, you will also sometimes see it develop a slight x-shaped bulge around the brace as it ages.

toman · #4 11-20-2006, 01:31 PM

I assume this was done to correct the problem of the flat backs sinking in, like my maple one has done? I wonder if these problems are really worth living with just to have the X-brace... What's the advantage of the X again?

John Sprague · #5 11-21-2006, 08:25 AM

Hi TONEMAN,

First there was a decision to make a flatback bass, immediately followed by some head-scratching about how to make it stay together. So, we use the X because it expands and contracts more in line with the way the back wood does. As opposed to using horizontal slats, which expand perpendicular to the back center seam, which "seams" to be a recipe for disaster.

The bulge, or tension and arch built into the brace, has two functions. When we get the tension just right on the back, we get a ton of sound out. Also, the arch strengthens the back in the exact same way a round back is stronger, cuz it's not flat! A little bit of arch can go a long way structurally speaking.

**Adrian Cho** · #6 11-21-2006, 08:56 AM

Bloody brilliant chaps!

I'm very happy with mine so far. I am for the first time in my life using Dampits and have two in the bass most of the time. Having a completely new bass yet alone a flatback is a new thing for me after having owned many roundbacks that were all at least 20 years old.