Bridge north/south placement in relation to f hole markings

There are so many factors with so many different basses, that I think it really depends on your instrument.

To me, it’s not worth the hassle of moving/resetting the soundpost and I think any small changes would probably be almost imperceptible.

There’s so many factors involved in a setup from the tailgut to the pegbox that it’s already sort of like hitting a moving target.

If anything, I’d reposition the soundpost and see how it responds before I tried actually moving the bridge.
Just my humble opinion.

 

The only real reason to move the bridge I can think of is to cheat it up a bit to “shorten” a long mensure. Of course, then you also have to move the soundpost and start from scratch in figuring out where to place it in relation to the bridge foot.

You also have to worry about how the new bridge placement will affect the fitting of the feet.

 

Move the bridge and answer your own question in five minutes......

 

Well, in five minutes any bass player can move the bridge but many of us are not qualified to also move the sound post. If you move the bridge without bringing the post along with it, you're basically making two changes at once.

 

Something else occurred to me:

Is it possible to simulate the effect of moving the soundpost north/south with respect to the bridge, by moving the bridge south/north and leaving the post where it is? Is the effect of changing the relative position of bridge foot/soundpost greater than the effect of moving the bridge and post up and down on the top plate? Is the answer to all these questions "it depends"?

 

If you move the bridge ½ - 1 cm upwards, in my opinion, you get a sense of how the bass would work with the sound post ½-1 cm downwards. I used to have the bridge positioned a bit higher than the "correct" place. Ofcourse it also gives other effects: slightly shorter scale length (lower tension). And at least on my bass, string height increased at bit, which was almost nescessary with my old bridge, which had been shortened through different adjustments and experiments. After a major repair, my new bridge is set up the "correct" place.

 

I moved my bridge up 1/2" on one of my basses with no noticeable effect on the sound or feel. I'm sure my luthier adjusted the SP accordingly.

 

I am a bit surprised that moving the bridge slightly upwards should make the feel stiffer. That was not my experience. And I can't help thinking, that the "stiffer" feeling is in fact just the effect of the strings being slightly higher from the fingerboard. But that is just my idea/theory.

 

But how can moving the bridge north raise the strings? If the default bridge position is at the peak of the belly arch, would not moving it forward put it on a downslope and thereby have the strings nearer the fingerboard?

 

Every bass responds different; there is no one definite answer. Your bass is not going to explode or forever sound like a sitar from a simple bridge or soundpost movement. Make a few small changes, see if you notice anything; make a few more. If there are no luthiers in your area, then invest in or make a set of soundpost tools, educate yourself, and then become the go to guy for your area. That is how most luthiers get started and learn.

We are talking about simple small adjustments, not major modifications. A search on talkbass will give you all the information you need to proceed. Soundpost adjustment is not semiconductor physics. It should be basic life skills for all bass players, like changing a car tire when you get a flat. I have confidence that you and everyone here can do it. Time to leave the nest grasshopper...

 

Every bass I've ever owned has maintained the same arching for some distance above and below the 'ideal' bridge location. Around 8" or so below the bridge and considerably more above. Put another way, the arching at the centre seam is pretty consistent for almost 2/3rds of the total belly length. If you move the bridge a 1/2" north, the bridge feet should not be any lower on the belly arching than they would be when lined up with the F hole nicks. The only thing that changes is the angle of the strings coming off the bridge. Because the bridge is now closer to the top nut, the angle of the strings coming off the bridge increases on the fingerboard side and raises the string height. I really didn't get it until a luthier showed me on my bass, but it's probably easier to just draw the two scenarios on paper.

 

In short because the plane of the belly around its middle/apex is not parallel to the fingerboard.

 

I made an experiment just a moment ago. I recently purchased a new bridge blank. I fitted the feet carefully and made the crown and the string slots so that the bridge is totally centered and stands correctly right in the center of the f hole notches. Currently there are no adjusters, I left them off in purpose in order to find out if a solid bridge would sound better. I was happy with the string height too, which I also left a bit higher than what I have used to.

The bass has now been very loud with the Spiro mittels, but also sounds a little twangy and there is a little bit too much high end in the sound than I desire. Due to higher strings it has also felt that there is more tension that I would need or want. Generally typical symptons of a too tight sound post, if I can caracterise it somehow.

Instead of tweaking the sound post I desided to move the bridge a little. I just moved it a couple of mm to the south, and a couple of mm to the bass bar side.

As the result the G string is now a bit lower than previously, and the E is a bit higher accordingly. Moving the foot towards the bass bar seems to have added more bass to the sound, and the E string is really roaring, especially with the bow.

Moving the bridge to the south also took a lot of the extra tension off, and the bass feels a lot easier to play.

I’m quite surprised how huge difference such minor adjustments made to the sound and overall playability. The bridge is such little bit off-centered that you must look really carefully to even notice it. I think I just leave it as it is and enjoy.