Double Bass Wolf tone gone w/new bridge

[powerbass]

My Thompson RM200 had a nasty Ab wolf tone ever since I bought it 5 yrs ago. I put on a wolf tone eliminator (small weight on string), I changed the tailpiece from ebony to wire and tweaked the sound post, some improvement but not much. Yesterday I finally replaced the bridge, the original one was warping, the legs were splaying, it has delrin adjusters, the end was near. The new bridge has 2 piece aluminum adjusters, right now the adjusters are all the way down-no space, I'll probably need to re cut the string edge when the weather dries out and the string height changes. The wolf tone is gone! Arco the bass is more articulate, notes are crisp. For those struggling w/wolf tones you might try changing the bridge. This was my first attempt at fitting a bridge I'm thinking about making 2 more bridges without adjusters - a winter one and a summer one. Do any of you have non adjustable bridges and swap them out?

 

[Don Kasper]

My Thompson RM200 had a nasty Ab wolf tone ever since I bought it 5 yrs ago. I put on a wolf tone eliminator (small weight on string), I changed the tailpiece from ebony to wire and tweaked the sound post, some improvement but not much. Yesterday I finally replaced the bridge, the original one was warping, the legs were splaying, it has delrin adjusters, the end was near. The new bridge has 2 piece aluminum adjusters, right now the adjusters are all the way down-no space, I'll probably need to re cut the string edge when the weather dries out and the string height changes. The wolf tone is gone! Arco the bass is more articulate, notes are crisp. For those struggling w/wolf tones you might try changing the bridge. This was my first attempt at fitting a bridge I'm thinking about making 2 more bridges without adjusters - a winter one and a summer one. Do any of you have non adjustable bridges and swap them out?

Here is a variation of the old "summer/winter" bridges question - this was discussed in a prior thread in this Forum - adjustable bridge
It is more rigid that a typical adjustable bridge because BOTH ends of the stud are threaded, hence less "slop" - unlike a standard adjustable bridge, where one half (is non-threaded) and is inserted into a non-threaded (and some would say intentionally "sloppy") blind hole.
It was not well-received by the community, as I recall! It was on my bass for more that a few years and functioned beautifully. The tension on the strings needs to be released enough so that the feet can be turned to the desired position.
Good Luck.

 

[Ortsom]

OP: have you weighed your new bridge prior to mounting it? With all dimensions (like feet width, depth & position, height of bridge & location of strings) hardly changed, I suspect there is a difference in weight between the 2 bridges which causes a change in one of the instrument's resonance frequencies. Bridge balance & orientation can also contribute.

Do any of you have non adjustable bridges and swap them out?

Yes, one one of my instruments, a fully carved one, I have 2 bridges with a slightly different height, 1 French & 1 Belgian. Sound-wise I find it difficult to hear a difference between them, but the Belgian being slightly longer-legged & lighter seems a bit more powerful & brighter. Also, visually I prefer the Belgian looks. The Belgian is slightly lower in string height. Lately I don't change the bridges, when string height needs to come up I slide a 0.75mm wooden shim below each feet, and take those out as required. "a 0.75mm wooden shim" = a bit of veneer.

This very old type of height adjustment is essentially a comparable approach to Don's bridge above, though each full turn of his foot might be more than 0.75mm (I estimate that at about 1.1mm). And the other difference is that the steel adds a little bit more weight, and more flexibility. In a properly balanced bridge flexibility in the up-down direction is irrelevant (in the absence of load in that direction), but on a strongly curved top flexibility in the sideways direction is less desirable. In both cases you need to take the tension off for height adjustment; neither of them are suitable on a set.

I know there is an internet document somewhere of some student comparing the effects of various height adjusters, I remember having scanned it, but the results have not stuck in my mind, for one reason or another. The effect of the extra weight on the location of the adjuster is easily assessed if you make 2 small jigs (with a weight equal to the weight gain due to adjusters). Put them on to simulate with adjusters, take them off to simulate without (no, to be without).

In some cases such a localised weight difference can impact resonance modes, but I have not actually observed that. What I have seen are minor effects along the lines of the old adagio: less weight = louder. Also that low, the extra weight acts as a little bit as a mute, though obviously not nearly as strongly as high-up on the crest, where mutes are normally placed.

 

[powerbass]

If I as to guess as to what made the biggest difference is the new bridge is more stable and rigid-vibrations from the strings are transmitted more efficiently. Intuitively it makes sense that a non adjustable bridge creates a more solid linkage for vibration, figuring out exactly how much my bass moved seasonally and swapping the bridges out requires more work than just turning the adjusters.

 

[Ortsom]

Oh yes, turning adjusters is very easy & highly desirable for long sets too. You asked; choose whatever fits your priorities.