I was looking for pearls on the net and found this:
http://www.lutherie.net/afterlength-scale.html
So Dude calls the strings on the non-business side of the bridge "afterlength." He goes on to state that it matters on violins but speculates that it does NOT matter on banjoes. So I wondered about CBGs! Well, that sure puzzled me! I decided to put it before the nation.
Has anyone expressly experimented with the string length on the short side of the bridge? What lessons can you share?
Uh... I can see this migrating to a discussion of bridge position. I think bridge position is addressed in the CBN archives, so I hope to see a focus on the afterlength. Let's assume a fixed scale length and bridge position at "about a third of box length from end" or whatever you prefer. I think your only options are to either stretch the box or extend the tail piece (or long through-neck - same thing, right?).
What says the nation?
Replies
i've used long string afterlengths and short string afterlengths, but the thing that seemed to make the best difference (especially with sustain) was the metal string anchor pins on the tail of the through neck, are they the "pin bridges" as i think Keni referred to them..? i use pop rivets with the pin removed to slide the strings into, i adjust the bridge to the correct scale length (25.5" usually) which is resting on the solid part of the through neck below the box lid, and turn the bridge at a slight angle to improve the intonation. (-:
Steve..I'm assuming Kenny is talking about the conventional type of acoustic guitar bridge with a fixed glued-on bridge, a plastic or bone saddle, holes thru' the bridge and top and plastic/bone/wood pins to anchor the strings. I've made guitars this way with good results, but they are a lot more work than a simple floating bridge.
You actually bring up a very good topic. It is the string vibrational energy transferred to the bridge that vibrates the top (soundboard), and develops the tone inside the box and exits from the soundport(s). Building a CBG is a relatively easy project. Producing a superior tone acoustically is a whole other challenge. Many buiders place the bridge too far back toward the tail. Actually if you are not going to build the box, but use a actual cigar box, you are very restricted in regard to design. It is critical that the bridge is placed on the sweet spot on the box. (Were the top vibrates best to create a tone). Consideration of the length after the bridge creates the proper downward tension and the angle cuts the string so it vibrates strong. An angle that is too sharp or too gradual both create problema. I would encourge you to continue to work in this direction. Increasing your knowledge concerning acoustic consideration will only lead to a better sounding instrument. Thanks for sharing.
BTW: Tailpiece bridges are inferior to pin bridges for guitars. If you really want to develop sound, install pin bridges.
Kenni...that's the principle that I've always worked on, finding the sweet spot of the box, but boy have I been proved wrong! I've just been playing some guitars with the bridge set very close to the end of the box and It's caused me to re-think my ideas. These guitars have a strong acoustic sound and a very good amplified tone from their piezo pickup.
I'm definitely going to give this alternative approach a go on some of my next builds and see what happens...I'm sure it won't replace my regular way of building guitars, but I reckon it will add another flavour to what I'm doing. There's other differences in these particular guitars which are quite different to the way I do it...and it's re-awakened me to the idea of taking on board new ideas.
As regards pin bridges being inferior to tailpiece bridges, nobody told John D'Angelico and Jimmy D'Aquisto that, and they knocked out a few decent guitars in their time. Different strokes for different folks and vive la difference!
As long as you have a good downward string pressure from the bridge to the tailpiece, nothing else matters on the end.
Well... I did angle one neck a bit too much (as in box-to-neck scarf joint). It was not a deal killer, but the resulting bridge was a little taller than I preferred. When I set it for intonation, I was still at "about a third" from the end of the box, but the bridge-to-tail strings were rather steep. I think if accidentally bumped, that bridge would flop over!
(I haven't bumped the bridge (yet) and it plays OK. ...o-0 ... )
On the other hand, the guy at the link above may have it right. Maybe it doesn't matter per se, but only as a function of applying the downward pressure. Makes sense to me, Randy. Thanks!
Haven't really paid any attention to that stuff on my builds, just set the bridge for a scale length of 25.5" and let things fall where they may. Seems to work OK. I'm sure someone will have a different opinion, but I'm not looking at this stuff like it's rocket surgery, just having fun building my boxes and they seem to sound pretty good.