String Break Angle

[bluedolphin]

I’ve often seen it mentioned that the string break angle (from bridge to tailpiece) is critical to a good tone on a resonator guitar. 15 degrees has been quoted for a single cone, but what should the angle be for a tricone?

[robn]

Hi bluedolphin,

You are right that break angle changes can increase or decrease the down-pressure on the cone and so effect the tone of the guitar.

However, from all the work we have done I have to say that the exact break angle is not critical and that there is quite a margin of "acceptable" down-pressure for each guitar and for each cone type. The degree of break angle does not have to be exact.

String gauge has a significant effect. Some guitars may "sing" with 13-56 strings but be a little choked with 16-59s. Some may be weak with 13-56 and sing with 16-59s. Most will sing fine with both! It is only when you are getting to the margins of acceptable down pressure that you will notice a significant detrimental difference that is not in the bounds of acceptable.

The key thing about a good break angle is that it gives you set-up options. And this comes from the neck set not the position of the the tailpiece. I have seen many cheap reso guitars that have too shallow a neck set, so the action has to be kept high to maintain a break angle. When the action is lowered on these instruments the down-pressure is lost and the guitar either rattles or is very weak in tone.

When I assess guitars I look at the set-up options that the neck set angle provides and this is easiest to read by looking over the tail of the guitar at the break angle in relation to the neck set and action height. A high action and shallow break angle will give limited set-up options - but if you are a pure slide player and are going to fit heavy strings or consistently up-tune then such a guitar may be fine for you.

I've seen some film footage of Bukka White playing an old Duolian tuned up to between F and F# minor. You can be pretty sure that guitar had a shallow break angle (probably due to a bowed neck) or that tuning would have crushed the cone (he is not light fingered!). But, boy, did that guitar sound good ;D

Robin

[andys]

What would be nice is if there were tailpieces that were designed so that if you did have a resonator with a shallow break angle, you could have a bit of adjustment so that the strings werent pushed up by the front rim of the tailpiece.

People who play set neck Gibsons(and their derivatives), often have trouble with break angles over tune-a-matic bridges, especially when necks are not that angled. Often their solution is to screw the rear stop bar as far down into the body as it can go, to give a good break angle over the saddles. I knew of someone with a SG who had to feed his strings under the stop bar to get the strings to stay in the saddles. I think a neck re-set was wel overdue in this case!

With a resonator, I guess the answer would be using a shorter tailpiece, but then that may affect the string tension somewhat.

[pete1951]

An ugly but simple way to make angle larger is to string `from the top` so the strings pass under the front of the tail/p. You will then have the ball ends on top. PT

[snakestretcher]

Apr 7, 2009 9:39:23 GMT andys said:

What would be nice is if there were tailpieces that were designed so that if you did have a resonator with a shallow break angle, you could have a bit of adjustment so that the strings werent pushed up by the front rim of the tailpiece.

People who play set neck Gibsons(and their derivatives), often have trouble with break angles over tune-a-matic bridges, especially when necks are not that angled. Often their solution is to screw the rear stop bar as far down into the body as it can go, to give a good break angle over the saddles. I knew of someone with a SG who had to feed his strings under the stop bar to get the strings to stay in the saddles. I think a neck re-set was wel overdue in this case!

With a resonator, I guess the answer would be using a shorter tailpiece, but then that may affect the string tension somewhat.

I'm sure an adjustable height tailpiece would be a fairly simple proposition. Regarding string tension; isn't the pitch of a string a function of its tension? To reach a given pitch the string has to reach a given tension; therefore less tension=lower pitch and vice-versa.

[andys]

Apr 8, 2009 10:58:05 GMT snakestretcher said:

I'm sure an adjustable height tailpiece would be a fairly simple proposition. Regarding string tension; isn't the pitch of a string a function of its tension? To reach a given pitch the string has to reach a given tension; therefore less tension=lower pitch and vice-versa.

Its marginal but if a string is brought to pitch over a longer length it will affect how taut or loose the string is under the fingers. Thats why on shorter scale guitars, sometimes you need thicker strings to get the same note, without the strings being too loose.