Double Bass How much bridge curvature for arco?

[AndersLasson]

Hi,

I have a carved chinese bass that I really like. I play both pizz and arco, and I start to realize that the curvature of my bridge is rather large. This means that it is difficult to bow the tqo middle strings (A & D) without hitting the adjacent strings. It is doable if I sit and play, but it is somewhat hindering my playing.

I think I have a rather flat curvature of my bridge, which is good in a way, but I would like to have a little better bowability.

How to measure fingerboard and bridge curvature?
How much curvature/radius is needed for playing arco?
If I adjust the bridge, will I have to adjust the curvature of the fingerboard as well?

And yes, I have read the newbie links on setup, specifically the one on "String Height & Bridge Curvature -- Jazz & Orchestral" (http://www.talkbass.com/forum/f3/one-string-lower-action-volume-than-others-123782/)

Best regards, Anders

 

[Greg Clinkingbeard]

Anders,
Measuring my 3/4 bridge template shows a few things that may help you. First, I dress every fingerboard for easiest bowing which is about a 73mm radius, more or less. The template I use for bridge curvature is also on a 73mm radius. When drawing a line from the top of the E string to the top of the G the center of the bridge is about 11mm above that line. Although this may be confusing, I've done my best to be clear.
Occasionally, I'll see a bass with a thin, flat fingerboard which has to stay that way. Unless I know the bass will never be bowed it still gets a similar bridge. I may flatten it a bit but this curvature is best for bowing.
YMMV.

 

[Greg Clinkingbeard]

When I say the top of the E and G strings I really mean the point at which the top of the template where I have lines which mark the location of the string notches. Once the bridge is cut, those marks are closer to the center of each string.

This is the method I use and it is similar to the method used by other setup people in our shop. No doubt, others who frequent this place may use other methods or have different ideas as to what the final result should be.

 

[robobass]

...
If I adjust the bridge, will I have to adjust the curvature of the fingerboard as well?...

That's often the problem. If the fingerboard radius is not optimal, then it will limit how much you can alter the bridge curvature alone. And, if the board is thin and flat, it may not be possible to dress it with the desired radius. This can be a can of worms!

 

[Fran Diaz]

Anders,
Measuring my 3/4 bridge template shows a few things that may help you. First, I dress every fingerboard for easiest bowing which is about a 73mm radius, more or less. The template I use for bridge curvature is also on a 73mm radius. When drawing a line from the top of the E string to the top of the G the center of the bridge is about 11mm above that line. Although this may be confusing, I've done my best to be clear.
Occasionally, I'll see a bass with a thin, flat fingerboard which has to stay that way. Unless I know the bass will never be bowed it still gets a similar bridge. I may flatten it a bit but this curvature is best for bowing.
YMMV.

I measured my bridge and it's exactly like that.