Double backs

[Ray Ussery]

Very interested in this concept...I too noticed this issue long ago, and it was what I was referring to yesterday in my reference to Clarence White's large hole D28..
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I just never had brains enough to consider solving the problem with construction methods...of course this applies to other instruments as well as Ken mentioned, including lap steels :)

[John Parchem]

I will be very interested in how it sounds. Given that the second back does not need to support the guitar, you should have a lot of flexibility in chosing the tonewood, maybe even consider a top wood like spruce.

[Ken Hundley]

I hear ya Ken, you just got me thinkin.....my fingers just started walkin.......

[ken cierp]

Ken, I've been thinking about this for a long while -- I just don't know much about it, but it seems to me that the "out of phase" component is what gives a guitar some of resonance? After all, there is sound is coming directly off the face/front of the guitar and more sound is being reflected off the back through the sound-hole.

[Ken Hundley]

I think there are a couple of ways you could look at this. In my limited experience, it seems the heavier guitars, specifically those where the backs and sides are thicker, tend to be cannons, with rich, deep bass, and clear trebles...midranges can vary. The thinner guitars, or those built with woods of less mass, tend to be woodier and have vastly different colorations to their sounds. Granted, playing on your gut and off your gut have different sounds, but I think the less massive guitars are more affected by dampening the back, and lose some of the subtelties they are known for. Could having a double back simply be avoiding the dampening effect as well as adding mass to the guitar? Dunno....my uneducated guesses here.

If its a mass issue, adding a second back will help, as well as to reduce the dampening effect of Americas gut expansion initiative. If it is a frequency offset issue, I really have no idea, don't have the capability or understanding to test it....but I am sure interested in the possible outcomes. I may have to try to build a ported double back guitar just to see what it means....wonder how that would look with my "off the sound board" sound hole....especially if I chose spruce...call it the oreo cookie guitar?

It's an interesting concept, and I have no argument as to whether it effects the guitar tone or not, just don't have a great gut feel as to how yet.

Sorry if this is a little rambling, had some good wine at dinner. Think I'll go kickbox and work it off.

[Go4aRyd]

I played a hollow-back built by Tim McKnight, and I am now a fan. He has some good info on his website for the curious minded. (note - Tim also builds using "double sides." I love the stability that would create. Will try a few when I begin bending my own sides (if anyone still had Fox bender detailed plans, give me a shout).

[Rienk Ayers]

Has anyone tackled this type of build yet?

Ever since I read about McKnight's double back, I've wanted to add it into my line up of future builds.
Likewise, i'd like to try spruce as the inside back - and maybe even make the top out of a hardwood (similar to a solid Koa or Walnut) but have a spruce double back inside, to get a similar tone? Definitely interesting possibilities...