• TalkBass has been independent since 1998. Add your voice.
    Create a free account to reply to discussions, view embedded media, and browse with fewer display ads.
    Join freeLog in
    Want zero display ads or expanded classifieds tools? Compare plans.

Double Bass bridge adjustment

I bought a new Thomann bass a year ago and the string heights seem too high. Because of current Covid situation I have decided not to visit a luthier in my nearest city (Granada, Spain) for the foreseeable future unless absolutely necessary, so I want to adjust the height myself. The factory set up when I assembled the bridge and strings gave me the following string heights (end of fingerboard to underside of string): E 10mm, A 12mm, D 11, G 8mm. I really want 6-7mm across the board. I'm a beginner, I play mostly jazz style and I rarely bow.
It's a non-adjustable bridge. Any tips or advice for shaving or sanding the feet of the bridge? Thanks, Antony.
 
from the description it sounds like a double bass.

220 grit sandpaper on the body under the bridge feet grit side up, slide the bridge side to side until the desired height is achieved.

you can always remove more you can't add less.
 
Can you show us a photo of the bridge?

image.png Here's a photo of the bridge.
 
No? No what?? Please explain. Thanks.

Do not sand the body to fit the bridge! You should get bridge adjusters installed by a pro. Then you can experiment. I would recommend string heights of 5,6,7,8mm, G-E. You can also go lower, depending on fingerboard dressing and possible buzzing. The crown of the bridge may need to be adjusted, too. It all has to be in balance for the best playing experience.
 
Slide the bridge slightly back towards the tailpiece and try a few different settings. That will drop the string height so you can see if those are your desired numbers. Don't obsess about any other details, the point is to test the string height, not to be afraid of your own shadow. Once you find a height that you like, you can move it back into the proper position and deepen the slots with a $5 chainsaw file. You can always move the bridge around, but once you remove material, you cannot add it to the bridge...

Adjusters and spending money at your local luthier are nice, but if you already have a decent working bridge, don't be afraid. Worst case scenario- you have to visit your local luthier ....
 
You might edit your post then, because your words literally say that.

No; WW does not say that. I see place the sandpaper on the body grit side up and move the bridge side to side. I personally would have said back and forth (in the same longtudinal plane as the bass itself), and use the grit to remove wood from the bridge feet. No one is suggesting having the grit side down on the body. I'm sure many of us have done this to shape bridge feet: tape sandpaper to the body, grit side up, placed the bridge on the grit and move backward and forward to shape the feet. The tape can even be dispensed with if there is another way to keep the paper stable.

I will say that on this bass those bridge feet do look too thick. Can't fault the slotting though.
 
First I would leave the E at 10 mm.
The bridge now has a nice curvature that gives a larger angle for the inner strings to avoid touching a neighbor string with the bow.
The G could be lower, I would take 6 mm for it. Not lower, at least not now, maybe later.

If you make the inner strings a lot lower, the bowing angle decreases. And don‘t forget, you cannot put material back.
So I would recommend to leave the inner strings a bit higher than a increasing string height progression like Eric recommended. I would do 6/8/11/10 mm from G to E.

The bridge feet are only roughly shaped to match the top if at all. The feet are too thick. Usually the feet get progressively thinner towards the outer edges ending in about a mm or less in thickness. The wood doesn’t need to be but from the bottom, it could also be taken from the top of the feet to reshape the feet.

I have reshaped my 5-string DB bridge for a larger bowing angle for each string and didn‘t got enough clearance on the highest one so I often touched the top with the bow. Just a little thing I didn‘t had on my radar when reshaping the bridge.
So the luthier has to change the adjustable bridge for a new pickup anyway and put some wood under the fingerboard to move the angles more towards the E side. Happy now, but that would not have been solvable with a bridge reshaping alone.

It‘s much less of a problem with a 4- string. But I think it would be a good idea to let a luthier correct the bridge, simply because I’m rather sure that the bridge feet are not well shaped to meet the top. Changing a well fitted bridge in string height is not so much of a problem. But progress slowly. Mount the bridge, tune up, check playing with the bow (even if you are not good at it).

If you start with the inner strings (A first by a mm down to 11), you can see what happens with the bowing angle for the A. It gets better again if you lower the D and for the D better when you lower the G. If you want to do this yourself do it that way. You still have room to go lower later or if the bridge feet needs fitting to the top which bridge the string heights a bit down.

Don’t lower perpendicular to the tangent at the bridge crown or you bring the strings closer together. Do it in parallel to the ribs. First make slot deeper (and wide enough that the string doesn’t get clamped), try and when you are happy file the wood away that is not needed.

It can help if you transfer the original shape on paper first, cut the paper and transfer that, a bit angled so that it fits the new files down string position for G and E. Then transfer that curve to the bridge. You might want to correct for D and A a bit but it is easier that way than doing it all by yourself and gets close to how it was before.

Good luck.
 
  • Like
Reactions: unbrokenchain
Many thanks for all the advice. I've ordered some various sized needle files and am going to start by filing down the string grooves, bit by bit.
BTW being English I don't understand the association between grit and food. In England, and here in Spain grit is something we just stick on sandpaper, or put on the road!
 
  • Like
Reactions: unbrokenchain