Bridge sizes vs tone

[John Bertotti]

The question, can anyone tell me how bridge base length and or bridge base width affect tone?

Thanks!

[Graham McDonald]

I think most experienced builders would agree that the length and width of a mandolin bridge will effect the tone, but I suspect that no-one has done enough, if any, experimental work to have any real conclusions. The bridge will add mass and cross-grain stiffness to the soundboard. This may, or may not be a good thing.

Cheers

[John Bertotti]

Might be a future experiment. I always wondered how we came upon the current adjustable bridge and why it is the size it is.

[Graham McDonald]

The Gibson adjustable bridge makes a lot of sense in a production environment such as Gibson in the early 20s. Mandolins, mandolas and guitars were always going to come off the production line with slightly different neck angles and different required bridge heights. Being able to adjust the bridge height with a few turns of a couple of knurled wheels is a lot easier than having to adjust the height of a one piece bridge by sanding or other non-reversible activities. One of the interesting outcomes is that the tonal qualities of the Gibson style adjustable bridge has become the expected standard of the carved top, f-hole mandolin rather than any other style of bridge.

[pops1]

While I am not sure about size comparison, weight comparison on the other hand does make a difference. So if larger size adds weight it may be a negative thing. Of course mandolins vary with what they need to sound good. Some may like a larger, heavier bridge. Some like a thicker pick, some a thinner one. It would be a complicated test.

[Marty Jacobson]

I think most builders would agree that you need these three things:

- Sufficient stiffness (whatever that means)
- Adequately fit bridge base (whatever that means)
- Minimal mass (whatever that means)
- Action which is not too high or too low
- Proper intonation

Everything else, like adjustability, are details which do not impact tone, as long as you have a "stiff, light bridge which is well fit, allows for good action, and plays in tune".

I made some faithful reproductions of the old Gibson aluminum bridge tops a few years ago. A few folks installed them and said they liked them. I haven't installed one myself. They are light, not as light as maple though, and exceedingly stiff.

A insufficiently stiff bridge, or a too-heavy bridge, or possibly a poorly-fit bridge will act like a low-pass filter (reducing high-frequency harmonic content).

A bridge cannot add anything which isn't already there in the wood/geometry/air/strings as system.

[John Bertotti]

I think most builders would agree that you need these three things:

- Sufficient stiffness (whatever that means)
- Adequately fit bridge base (whatever that means)
- Minimal mass (whatever that means)
- Action which is not too high or too low
- Proper intonation

Everything else, like adjustability, are details which do not impact tone, as long as you have a "stiff, light bridge which is well fit, allows for good action, and plays in tune".

I made some faithful reproductions of the old Gibson aluminum bridge tops a few years ago. A few folks installed them and said they liked them. I haven't installed one myself. They are light, not as light as maple though, and exceedingly stiff.

A insufficiently stiff bridge, or a too-heavy bridge, or possibly a poorly-fit bridge will act like a low-pass filter (reducing high-frequency harmonic content).

A bridge cannot add anything which isn't already there in the wood/geometry/air/strings as system.

Has anyone tried a bridge of CF? Stiff and light, I have considered going to a one piece bridge. I seem to have a good hold on the humirity of this mandolin and don't think that height adjustments will be needed. Actualy since getting it I think I have adjusted it once, that would cover a span of around 11 years.

[MontanaMatt]

Has anyone tried a bridge of CF? Stiff and light, I have considered going to a one piece bridge. I seem to have a good hold on the humirity of this mandolin and don't think that height adjustments will be needed. Actualy since getting it I think I have adjusted it once, that would cover a span of around 11 years.

I have to adjust my bridges twice a year...if I don't the action buzzes in the summer. Up in the spring, down in the fall.
Must be the altitude mixing with the cold winters?

[John Bertotti]

I have to adjust my bridges twice a year...if I don't the action buzzes in the summer. Up in the spring, down in the fall.
Must be the altitude mixing with the cold winters?

I keep an oasis in my case in the winter so I try to keep it humidified year round to eliminate that variation. In the case all the time as soon as the humidity gets below 40% here. This year I was down below 25% in my house, at its worse, even with a humidifier running, a big console humidifier that holds 5 gallons. I had to fill it every used about three gallons every 12 hours. All those weeks in single digits down to -35 + temps really takes its toll. I hope to have a cabinet built to keep all my instrumewnts in this winter so I can control the humidity in one spot only.

[Marty Jacobson]

Several of my mandolins have CF saddles. It doesn't sound any different from what I can tell. I'm pretty sure it'll never break, though!

CF is actually not particularly light, at twice the density of ebony. You can just make things a lot smaller, so you can get away with less mass if you design it correctly. A real, full-CF bridge of optimal thickness is so thin that you can't intonate it! It's thinner than a violin bridge. Mine are encased in wood so they have a traditional appearance.