Bridge contact with soundboard?

[mikerofone]

Relatively new to mandolin - should 100% of the bridge be in contact with the soundboard or just the outer “feet” of the bridge? I have a Big Mon and most of the bridge is in contact except for an “arched” area in the middle. To cop a descriptor someone else here used, it sounds a bit “sponges” at times.

[Ray(T)]

Some bridges have full contact and some have an arch in the middle. You’ll find people who will tell you that one type is better than the other but in my limited experience - 50 years playing and countless mandolins of each type - it makes little or no difference as long as whatever does touch the top is well fitted. If you are getting a “spongy” sound, there is likely something wrong but it might be something other than the bridge.

[Mark Gunter]

That’s one little part of a good setup on a new mandolin, to fit the bridge to the top. Evidently no setup has been done on yours.

I accomplish this by placing sandpaper with abrasive side up on the top plate and lapping the bridge by hand on the sandpaper until it conforms to the arch of the top.

I’m referring to the feet of the bridge, the entire portion of any bridge that is meant to touch the top should be fitted to the top.

[rickbella]

If you are getting a “spongy” sound, there is likely something wrong but it might be something other than the bridge.

In my experience, it may mean an internal brace has come loose.

[Bacfire]

And then there’s me; always an outlier. I bought an A Jr a few months ago with a very poorly fitted bridge (could slide paper under probably 30%+ of the bridge feet), but a huge sound. I had the nut slots cut down and the bridge properly fitted and… it lost a bunch of volume and resonance. Plays great though ��

[keith.rogers]

If it’s the original bridge and original location, I’m sure the Northfield folks had it right. It is possible that the bridge has been moved if all the strings were removed, or, worst case, poorly adjusted and “refit” poorly.

But, I’ve always wondered what sound a “sponge” makes that would apply to a mandolin. The word suggests a feel more than a sound, to me. Does it have a set of standard or original strings in good shape? Checked for anything loose that could be resonating? Etc?