# Ratio between the top part and the legs of a bridge

Discussion in 'Setup & Repair [DB]' started by Don C, Jan 7, 2012.

1. ### Don C

Jan 13, 2007
Victoria BC
I was reading on David Gage's website, the part about the set up of the soundpost, and bridge.
He says, the ratio of bridge top to legs should be 1 to 2.
In other words, the legs should be twice as high as the solid part of the bridge is.
I don't think I've ever seen a bridge cut in this manner, with the exception of a picture of Ron Carters bridge. In fact most I've seen tend to be a ratio of 1 to 1., and on some bridges the solid top part is more that 50% of the height.
So my question is, what does it do for the sound of the Bass ??

If I have a bridge that is a 1 to 1 ratio, and I have a bridge made that is a 1 to 2 ratio, what change in sound should I expect ?
I am very curious.

2. ### Matthew TuckerCommercial User

Aug 21, 2002
Sydney, Australia
Owner: Bresque Basses, Sydney Basses and Cellos
David's words on the subject are sufficiently vague to allow a number of interpretations. It depends where you measure the leg height from - the bottom of the arch? or the bottom of the heart? or some other measurement? And where do you measure bridge top? From the top of the heart to the crown? Bottom of the heart to the crown?

There is no formula, as it depends on the bass and the bridge blank, but generally, what you want to avoid is something like this where too much wood is taken off the top of the bridge:

(this is a picture of a reject bridge from Upton repair website - it was taken off a bass in for restoration ... they were NOT responsible for cutting this one!)

I often see this, after an inexperienced person installs a bridge with adjusters - the inexperienced installer then wonders why the bridge is now too tall and trims the crown rather then further down the legs and feet.

So there is an important structural aspect to it, and then there's the "fine tuning" aspect, as the bridge is a HF filter. The audible effects of bridge shaping can be subtle and depend on the model of the bass, the model of the bridge, and the budget of the owner. And I don't dare start to generalise about it here