Soundpost contact area

[JtheJazzMan]

Just trying to get an idea of what is normal in terms of the soundpost being flush with the top and back of the bass. 100% contact would be nice, but what is considered a poorly fitting soundpost?

[T-Bird]

Hi.

I've only fitted one for my main ply 3/4 (7/8?), one carved 1/2 I repaired and sold and a few carved cellos, so my experience is very limited, but I'd say 95%.

But for some reason that just feels natural to me as an engineer, I like to slightly chamfer or round the corners of the post, so that 5% is right there and the actual contact area is 100%.

Why do You ask BTW?

A smooth surface is IME easy enough to achieve and the flexible top and back will force the top and back to make a full 100% contact with the sound post. But if the sound post deforms the top and/or the back when the instrument is strung because the fit is not perfect, a carved top/back will crack. Plywood will just bend, but the result was audible, at least for me on my cheapo.

Regards
Sam

[JtheJazzMan]

Using some paper on a stick I got an idea of how well my soundpost is sitting in the bass...ie not very well. Maybe 60% contact.

Ive now decided its off to a luthier later in the week, hope the soundpost still fits correctly, and its just positioned incorrectly. Though its had the same SP since new and I am certain the bass top has changed shape slightly.

One of those soundpost hatches in the side of the bass seems like a nifty idea.....

[George700DL]

Originally Posted by T-Bird

Hi.

I've only fitted one for my main ply 3/4 (7/8?), one carved 1/2 I repaired and sold and a few carved cellos, so my experience is very limited, but I'd say 95%.

But for some reason that just feels natural to me as an engineer, I like to slightly chamfer or round the corners of the post, so that 5% is right there and the actual contact area is 100%.

Why do You ask BTW?

A smooth surface is IME easy enough to achieve and the flexible top and back will force the top and back to make a full 100% contact with the sound post. But if the sound post deforms the top and/or the back when the instrument is strung because the fit is not perfect, a carved top/back will crack. Plywood will just bend, but the result was audible, at least for me on my cheapo.

Regards
Sam

I did the same thing intuitively - chamfered edges. Just a tiny bit. I did this before I bought Chuck Traeger's book, by the way

Before I glued my top on, I also marked the same spot on the back and the top with a pencil. That gave me the initial location of the post. Whenever I moved it, I made sure it was the same distance from that spot on the top and the back.

Anybody else keep a small string tied to their soundpost?

George

[bassedsouth]

Anybody else keep a small string tied to their soundpost?

George[/quote]

I use string 'lassoed' to the top of the post when positioning it / its a real life saver in helping with setting the post I find. When Im happy with the fit I cut the string off through the f hole.

[George700DL]

Originally Posted by bassedsouth

I use string 'lassoed' to the top of the post when positioning it / its a real life saver in helping with setting the post I find. When Im happy with the fit I cut the string off through the f hole.

I used a noose knot that self-tightens and stays tight, also near the top of the post.

Except I keep it there for future movement I just throw the rest of the string back in the bass when I'm done.

George

[MIKMAN]

Originally Posted by George700DL

I used a noose knot that self-tightens and stays tight, also near the top of the post.

Except I keep it there for future movement I just throw the rest of the string back in the bass when I'm done.

George

I do exactly the same, not only in my basses but also in my violins. Very helpful for tweaking with soundposts!