MIMF

I've been tinkering with ways to improve the tonal quality of my acoustic slimline guitars, and now I'm considering the idea of placing a sound post under the bridge, like found in the violin family. Any thoughts? Has it been tried before?

Not a good idea unless you are going to play it with a bow. A sound post in a plucked string instrument is rather self defeating for sound production. It has been tried many times and always discarded.

Michael is correct for purely acoustic, acoustic-electric is another story. A sound post is an effective measure to reduce feedback, I'm guessing it's affect on tone would depend on a lot of other factors.

I did this very thing on my Guild thinline Starfire III about 25 years ago, and played it that way for a very long time. In fact, I used a sound post under each end of the bridge. Then I got rid of them, and much preferred the sound afterwards. But I was always playing amplified. I can't imagine that this would work AT ALL with an acoustic instrument. But you can go ahead and try it. You won't be convinced of the result until you try it. Use only a drop of glue (better still, no glue at all) on your sound post (s), because I am confident you will be taking it (them) out of there about a day after you first try playing your guitar with a sound post or two.

I know that it has been tried in guitars. However, I recently tried in a mandolin with a quite amazing result. The system I used was not a soundpost per se, but what I call a "truss". It improved the sustain and the amplitude noticeably and the guy I sold it to raves about it. Sorry about the poor quality pic....it's the only one I have.

Interesting to say the least!
Was it mounted between the braces?

It looks like the shape of the Eiffal Tower.

http://www.guardian.co.uk/world/video/2 ... ment-video

Bob Francis wrote:Interesting to say the least!
Was it mounted between the braces?

Fitted to the curved surface of the back directly behind the bottom brace and fitted onto a flattened surface of the belly brace. What you can't see are three "half diameter" cutouts mirroring the bottom of the bridge....hidden behind the back brace.

I have to say that this mando was hollow in sound and lacked projection without the truss. Only God knows what made me do it! But on this instrument....it works. I am not recommending it as a panacea for the ills of an instrument, and I don't believe it would work in a guitar. However, being open to all manner of crazy ideas, I do believe that there is more to know about this phenomenon.

Barry Daniels wrote:It looks like the shape of the Eiffal Tower.

http://www.guardian.co.uk/world/video/2 ... ment-video

Hey Barry, if are you inferring that I'm as crazy as those tower tappers, then I resemble that remark!!!

I tried a soundpost before as well. In an a classical guitar.
It certainly extended the sustain, but killed the richness in the tone of that guitar.
It stops the top and back from moving independently, so the body can no longer "breathe".

Chuck Tweedy wrote:I tried a soundpost before as well. In an a classical guitar.
It certainly extended the sustain, but killed the richness in the tone of that guitar.
It stops the top and back from moving independently, so the body can no longer "breathe".

Hey Chuck, I wonder if the richness of tone could be maintained if a bass bar was introduced to a flat top guitar. The basic idea of a sound post is to provide an "island" or fulcrum about which the bass bar rocks and pumps the belly. Maybe a different bracing system incorporating a bass bar could change that whole dynamic........just thinkin' out loud!

It would probably sound like a large violin.

Probably, but aren't you wondering just a little? Anyway, what's a "large violin" sound like? A flat guitar soundboard vibrates more and vibrates differently than an arched violin plate. Maybe I'm playing devil's advocate, but curiosity never hurt anyone but a cat!

A violin is bowed and not plucked. (most of the time.) If the guitars' sound took on the character of a violin, it would resemble a plucked violin, not a bowed one- it kills the tone because the string cannot drive the top in the same way.

Barry Guest wrote:... but aren't you wondering just a little? Anyway, what's a "large violin" sound like? ....

Hmm I think its called a "double bass". Sounds pretty good to me.

I have seen this come up many times on this and other forums. Everyone who tried it said that it was not beneficial.

Hey Chuck, I wonder if the richness of tone could be maintained if a bass bar was introduced to a flat top guitar. The basic idea of a sound post is to provide an "island" or fulcrum about which the bass bar rocks and pumps the belly. Maybe a different bracing system incorporating a bass bar could change that whole dynamic........just thinkin' out loud!

I think that is the "crux" of the problem Barry (and Barry)
The guitar top is not structured to work well with a post. Sticking one in there just throws the whole system off.
Further, structuring a guitar like a violin-family instrument (i.e. post under one end of bridge, BB under the other) is also probably not going to work.

So, to make it better one might move the post further from the bridge to get more freedom in the top.
The further away, the better, so LutheirX keeps moving the post toward the rib until ... it is at the rib. and...
We're back to where we started.

Barry G. - What was the motivation to try the truss?

Andrew Porter wrote:Barry G. - What was the motivation to try the truss?

Andrew,

My motivation was to see if I could "deaden" the hollow sound that the mandolin initially produced. I had no idea if it would work, but it did.....increasing sustain and clarity.