Neck Block

[Jeff Bollbach]

He means that as you raise the bridge the pitch goes sharp. Of course you would then tune down to compensate.

[wellspal]

Okay, thanks Jeff, helps a little, but now I'm really confused, more than the little monk-men going up and down the staircase at the same time.

You say try raising the saddle to decrease the tension on the top. I say how can any tension be decreased as one re-tunes back to the constant pitch. (I just learned this by the way, it's really elementary you know.)

Never mind all that, back to square one. If you were going to do an experiment where you raise the saddle a bit, how much would you raise it?

[anonymous0726]

Originally posted by Pete OLeary
...setting the neck further out from the top will increase the angle (towards 180 deg.)...

Except that the bridge is then raised to adjust string height in relation to the fingerboard so that the angle on the neck side then stays the same. Force from the saddle side would increase from the changed angle. Right?

[Pete OLeary]

Originally posted by wellspal
So Pete, just to be perfectly clear, what you are saying is as I raise the upper portion of my $175.00 wooden wheel bridge the tension or pitch as in pitch pipe is staying the same?

Of course not. The the tension on the string will increase and pitch will increase correspondingly. Also the force downward to the table will increase. Force on the table will also increase just by tuning the string to a higher pitch. You effectively did both with your test, because you did not "retune" the string to the same tension. You changed two variables, that is why I said your test is flawed.

Again, it is an application of elementary geometry and statics. Sometimes this is called mechanics.
This diagram shows the resultant force [R] upon the table with string tension [F] and break angle [ø] known.

[Pete OLeary]

Originally posted by Ray Parker


Except that the bridge is then raised to adjust string height in relation to the fingerboard so that the angle on the neck side then stays the same. Force from the saddle side would increase from the changed angle. Right?

This is correct, assuming the bridge is raised to compensate for the difference. Then the net break angle remains the same, hence the force to the table remains the same, though the line of force through the bridge will be altered slightly.
Assuming the saddle is at normal (low) height and equal tension strings are used, the only way to increase the force to the table is to reset the neck so that it tilts back. It's only geometry.
Seems like some basses like more force on the top, some less. To me, thicker and laminated tops seem to want more force. When these basses are strung with gut or other low tension strings, they seem to die out. Short of a neck reset, a slightly shorter soundpost seems to help with projection.

[sean p]

this may be a whole new can of worms, but

individual characteristics of various basses notwithstanding, is it generally the case that strings respond quicker under the bow at higher tensions?

sean p

[wellspal]

I learned a lot in the last few days. Sorry Sean, can't help you with the bow question. But here is what I learned.. I think. On some basses if you lessen the FORCE TO THE TOP, tone will improve. Some basses will sound better with more FORCE TO THE TOP. But do not get confused about FORCE TO THE TOP and STRING TENSION. String tension can only be governed by the strings themselves and scale length. And to Ray and Pete if your math is absolutely perfect, it still doesn't take in the FLEX of the top (where the hell does "table" come from btw) and if my son won't loan me his really expensive calculator and how to use it, well, how does the math help?

[anonymous0726]

If you measure the angles with he strings up to pitch, then the top has already flexed.

[Don Higdon]

Originally posted by Ray Parker
If you measure the angles with he strings up to pitch, then the top has already flexed.

The flex is limited by the soundpost, and is not enough to meaningfully alter the string/bridge angles. Lou DeLeone showed me his invention for measuring this.

[wellspal]

Invention? Please expound.

[Don Higdon]

Calipers connected to a sweep hand dial capable of measuring less than .001" movement.

[arnoldschnitzer]

IMHO Ray Parker has his thinking right. When you increase the breakover angle at the bridge you increase the pressure that the bridge exerts on the top. It's pretty standard in my shop to change the neck angle when bringing it up out of the mortise. Otherwise the bridge gets real high and you do indeed have an increase in breakover angle, and therefore tension on the top. Of course, sometimes you want a higher bridge. If the top is weak or old (or both, like me) it often helps the feel and wolfiness to raise the saddle up a bit. I like Bollbach's raised saddle method. Of course, I taught it to him. I pretty much taught him everything he knows. LOL!

[wellspal]

Just what is the reason one of you guys hasn't written a book on db fundamentals. That is set-up and how to get the best sound from your particular bass? Is the number of db players/buyers so low it's just not worth it? How many db players are there? Statistics anyone? It seems every other instrument has its own modern day book of what's what.

[arnoldschnitzer]

My book is actually in the works. I'm hoping to finish it after I paint the house...which I'll be getting to after I put up the new fence...and I'm going to start on that after Little League season...oh wait; I forgot, I promised my wife I would dig up the dead azaleas...estimated year of publication: 2036

[wellspal]

what if i paint your house for you and mend the fence and in return you share what you know into a tape recorder and i'll write the damn book?

[Marcus Johnson]

Sounds like a plan; what say we all meet up at Arnold's house, one week from today?