Double Bass Please Define String "Afterlength"

Bob Knebel said:

Is this the distance from the underside of the bridge to the tailpiece "fret" (if that is the right term .... i.e. the raised portion on the tailpiece that the string breaks over)?

My reason for asking is: My luthier replaced the old Kay tailpiece "coat hanger" wire with flex cable and now the tailpiece floats about 2.5" to 3" higher up towards the bridge than it did with the original Kay tailpiece wire. I've been reading threads about afterlength tuning, etc. and it seems like my afterlength is a fair piece shorter than the "1/6 of vibrating string length" rule-of-thumb. If I correctly defined afterlength in the first sentence, then my current afterlength is 6" (as opposed to a calculated 7.5" afterlength). The bass sounds OK but I do have problems with upper string silks (G & E) rolling over onto the tuning pegs without adding spacers to the tailpiece barrels of the strings. I'm about to re-string with guts so silks are not a issue but .... would it be advisable to shorten the tailpiece wire and lower the tailpiece while I've got the strings off? Thanks in advance.

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7" would be about right for a Kay (with a 42" SL) if you are going to use the 1/6 rule. It will definitely be advisable to shorten the tailgut/wire while you have the strings off.

You might also consider the modal tuning of the assembly below the bridge. I use a tap method on the tail piece, and then tap up on the lower bout by the bridge, try to get the sound of the thump (although octave apart) as close as possible by shortning or lengthening the cable.

dennis duvall said:

You might also consider the modal tuning of the assembly below the bridge. I use a tap method on the tail piece, and then tap up on the lower bout by the bridge, try to get the sound of the thump (although octave apart) as close as possible by shortning or lengthening the cable.

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….ooohhhh this is interesting. I have heard of tap tuning a banjo drum but not a bass. Can you explain more please (in novice language if possible)?

Yea that looks kinda close in the picture there.

Why do you suppose he did that?

Bob Knebel said:

Thanks a bunch Bob ... I appreciate the advice. I don't know if I will get heavily into trying to tune the afterlengths but at least I will know I'm in the right ballpark compared to where the tailpiece is now. Happy Holidays.

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I wouldn't worry about the "tuning" of the afterlength. One guy will tell you it should be this interval and six other people will tell you six different intervals. I remember one guy saying that it should be "any" interval. I've tried a bunch of different intervals over the years and found the old 1/6 rule worked as good as any. I've measured the afterlength of basses whose owners thought the afterlength tuning helped and they were usually pretty close to 1/6 of the string length. My personal opinion is that afterlength tuning is a waste of time. The only tuning that I've seen that seemed to work is that of actually matching the vibrating frequency of the tailpiece (wood) to half of the resonance frequency of the body and even then the difference is minuscule

We experimented with moving the tailpiece north on a bass that had a tight feel. It seemed that the strings felt less tense (pizz) as the TP got closer to the bridge. The sound didn't seem to change. Finally used a raised saddle to cure the "tightness" problem.

Bob

Other than the string length south of the bridge, the other issue you raised (and which doesn't seem to have been discussed yet here) is the effect of the tailpiece wire length.

From the picture and what you said, it seems this wire is now 2 or 3 inches.

I experimented a bit with this because my bass is a fairly large 3/4, and with the string length as it was set up by the luthier, I had a wolftone of the bass was resounding on the A string at about G.

So I did two things to avoid the wolftone. I went to a Pecanic "compensated" tailpiece that creates different stringlengths below the bridge, and I also lengthened the tailpiece wire. I still have the wolftone, but the A string does not resound very much anymore, not nearly as badly.

I read somewhere (Chuck Traeger's book) that lengthening the tailpiece wire gives a brighter sound with more punch and volume (better for jazz pizz) and a shorter wire gives a deeper darker arco sound. On my bass at least, that was the case. The longer tailpiece wire is also supposed to raise the wood note of the tailpiece (I cannot confirm that, and I am not trying to match modes -- you need electronic frequency measuring gear).

But I would be interested to know: Did you notice any change in the sound of your bass with the longer wire?

As Bob mentioned, even the most careful matching or tuning of components make only a slight change in the Bass.

Even with real good Basses change is change but they sound good no matter what you do to them. Only, you may like the new sound better or rather a different flavor of the week.

People do get bored with their Basses sometimes. Often it's the seasonal changes that require adjustments to the Bass or soundpost. It could also be the strings have internally stretched beyond the manufactures intended performance and need to be changed.

I just checked two Basses of mine in the rack. One is tuned with the G at 2 octaves and a 4th and the other strings a b5th. My other Bass is about 2 and a 5th all across. That Bass I recall letting the Tailwire up about a year or so ago. At that time I felt it loosened up the tension just a bit. I use Stark Flexocor 92s with a C-ext on that Bass.

I usually set my Basses once unless it feels way wrong. Then I make the necessary changes and leave it.

Since these changes only alter the sound or feel of the Bass slightly, I suggest that IF you keep fiddling with your Bass week to week looking for 'that' sound than maybe it's time to start shopping for a new and better Bass..