Upper bout radius - or flat?

[Kent H]

Ken

What are the benefits of different top radii?

Is there a breakdown of old Martin/Gibson numbers versus new builder numbers?


Thanks

[ken cierp]

The two main benefits of the domed sound-board are appearance without a slight dome a plate will tend look concave -- pretty ugly when that happens. Most importantly a contoured plate is slightly larger in surface area than a flat plate that covers the same perimeter boundaries. So if the sound board shrinks due to low humidity it will flatten rather than crack -- contrary to conventional wisdom a domed top is not necessarily stronger. Martin uses a 52' radius (28' often talked about is a pure myth) on their main sound board braces. Gibson's varied over the years and don't forget that some of their flat tops were actually carved top models that evolved into flat tops. Gibson did and does advertise that some models have domed sound boards, can't remember what the claims are?

Most makers agree that doming the sound-board reduces bass response and therefore the perception is that the trebles have been accentuated.

Can you construct a guitar with a perfectly flat top? Certainly -- its done all the time, matter of fact the very top of the line R Taylor's advertise and brag about their "perfectly flat topped" guitar.

[Kent H]

Thanks!

I knew the concept behind it, just curious about what goes into the choices for the amount decided upon.

More bass, etc.

[ken cierp]

Most makers agree that doming the sound-board reduces bass response and therefore the perception is that the trebles have been accentuated.

[Tim Benware]

Most makers agree that doming the sound-board reduces bass response and therefore the perception is that the trebles have been accentuated.

So they say but I can't tell the difference.

[Kevin in California]

Just remember you have to be careful about believing what the "They" brothers say because all they've been trying to make a name for themselves for years. :)