DantheBanjoMan - Posted - 07/23/2011:  09:12:40

I've taken a few photographs to show why Steve's tests and my own might be very different.  I have two banjos which have very similar scale lengths, and old beater Gibson RB 100 and an Epiphone MB 250.  If I measure the distance between any of the frets the two instruments are nearly identical.  Here is the distance from the first fret to the second, but it's the same all the way up the neck. 

Epiphone Banjo-Distance from fret one to fret two

Gibson Banjo-Distance from fret one to fret two

rudy - Posted - 07/23/2011:  09:34:55

quote:

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Originally posted by steve davis



I'd be happy to send you one of my compensated bridges to try,Rudy.You might be surprised.

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 Steve, Thanks for the offer, that's very nice of you.  I've made a few compensated bridges of my own, but reverted back to a straight design as my personal preference.  I've been doing a "traditional" design with a thin layer of ebony sandwiched between two layers of quartersawn violin grade maple.  I'm pretty happy with them.

You COULD send me that Vibrolux for my Tele, though....

DantheBanjoMan - Posted - 07/23/2011:  09:41:18

However, the distance from the first fret to the nut is a different story.  The distance from the nut to the first fret is considerably shorter on the Gibson than it is on the Epiphone.  Clearly this will have an effect on intonation, and while bridge placement or a compensated bridge might help, a difference at the nut end of the banjo is best addressed at the nut.

So what is going on here?   Gibson shortened the distance from the first fret to the nut, and I know this because the distance from the first fret to the nut is nearly identical when, according to the mathematical formula, the distance from the first fret to the nut should be a tad longer.

I'm guessing that Steve did his tests on a high-end instrument and because it likely has some kind of compensation his bridge brings the banjo into pretty precise intonation.  I'm sure that if I put his bridge on my Gibson it would take care of all intonation problems. 

On the Epiphone his bridge would make things much better as would carefully positioning the bridge, but in addition to those fixes banjos like my Epiphone would benefit from a compensated nut.  Using a single string as a test so bridge compensation is not an issue, according to my electronic tuners it is impossible to position the bridge so it plays in perfect tune up and down the neck.

My my Martin gutiar (and probably all recent Martins) , my Gibson banjo (and probably many others), all Stelling banjos, all recently made Washburn guitars, and all instruments that have been retrofitted with the Buzz Feiten system have some kind of compensation at the nut, so perhaps it wise to think twice before dismissing the role of the nut in banjo intonation.

From the Stelling website:  "Since intonation has been an inherent problem on stringed instruments, Geoff has since devised a compensated nut that nearly perfects the intonation on all models of Stelling banjos. By selectively notching the nut slots to different lengths, relative string distance from the nut to each fret is adjusted. This adjustment to the nut is one of several final operations Geoff Stelling performs on every banjo."

Epiphone Banjo-Distance from Nut to First Fret

Gibson Banjo-Distance from nut to first fret

DantheBanjoMan - Posted - 07/23/2011:  10:01:52

Several months ago I did quite a bit of testing testing.  I made a secondary nut (from a piece of binding) that I could scoot back and forth on the fingerboard so  I could adjust both bridge and nut placement.  Rather than rely on my ear alone, I used a good electronic tuners and enlisted the help of a friend who is a has a very precise ear (she's a classically trained orchestral musician who is just finishing up her master's degree) and did some experiments, and it turned out the way you would expect it would.  Compensating the bridge helped, as did compensating the nut, but the most precise intonation was achieved by making compensations at both the bridge and the nut.

Testing the Concept

Frebazak - Posted - 07/23/2011:  15:42:03

I'll throw in my two cents... I bought a banjola from Dan a few months ago. He had put a compensated nut on it . It plays in tune up and down the neck...and,... it plays brighter. I played the same exact same model at Elderlys a few weeks ago and the difference was immediately noticeable....

JoeDownes - Posted - 07/23/2011:  17:45:02

Here's a great description of all kinds of compensation issues: guitarsetup.co.uk/nuts-about-i...ation.php

Here's another interesting article about building a compensated nut: mimf.com/nutcomp/

uncle.fogey - Posted - 07/24/2011:  12:54:03

quote:

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Originally posted by DantheBanjoMan

However, the distance from the first fret to the nut is a different story.  The distance from the nut to the first fret is considerably shorter on the Gibson than it is on the Epiphone.  Clearly this will have an effect on intonation, and while bridge placement or a compensated bridge might help, a difference at the nut end of the banjo is best addressed at the nut.

So what is going on here?   Gibson shortened the distance from the first fret to the nut, and I know this because the distance from the first fret to the nut is nearly identical when, according to the mathematical formula, the distance from the first fret to the nut should be a tad longer.

I'm guessing that Steve did his tests on a high-end instrument and because it likely has some kind of compensation his bridge brings the banjo into pretty precise intonation.  I'm sure that if I put his bridge on my Gibson it would take care of all intonation problems. 

On the Epiphone his bridge would make things much better as would carefully positioning the bridge, but in addition to those fixes banjos like my Epiphone would benefit from a compensated nut.  Using a single string as a test so bridge compensation is not an issue, according to my electronic tuners it is impossible to position the bridge so it plays in perfect tune up and down the neck.

My my Martin gutiar (and probably all recent Martins) , my Gibson banjo (and probably many others), all Stelling banjos, all recently made Washburn guitars, and all instruments that have been retrofitted with the Buzz Feiten system have some kind of compensation at the nut, so perhaps it wise to think twice before dismissing the role of the nut in banjo intonation.

From the Stelling website:  "Since intonation has been an inherent problem on stringed instruments, Geoff has since devised a compensated nut that nearly perfects the intonation on all models of Stelling banjos. By selectively notching the nut slots to different lengths, relative string distance from the nut to each fret is adjusted. This adjustment to the nut is one of several final operations Geoff Stelling performs on every banjo."

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Very interesting, Dan,

Part of my cynicism about compensated bridges comes from the fact that I use a capo more often than not, and have 3 longnecks, hence my favoritism for the bridge end.

I am not familiar with anything Martin has done with nuts, but they make them from Micarta, so they could easily mold the bridge in some subtle way.

As for the difference in the first fret of Gibson vs Fender (assuming they are the same scale), it's VERY tough to get nut slots cut so that the strings bear exactly on what would be the center point of a fret, if there was one up there (never a problem with longneck capoed at the third fret) - I don't know how to do it, which is the salient arguement for a zero fret, and there waqs a VERY LONG thread about this recently, with a lot of emotional content.

My guess about Gibson vs Fender is that you're better to err on the side of having the first fret a little closer, which would slightly flatten the notes, but that would be mitigated when you fret or capo, which slightly sharpens the note, so you're even-Steven.  Also, that gives more leeway for improperly cut nut-slots.  The compensation of bridges and nuts always compensates for sharpness, not flatness.

Honestly, a zero fret ends all this misery and cuts through all the conjecture, but I know it will never happen with banjos.

DantheBanjoMan - Posted - 07/24/2011:  17:38:00

Uncle Fogey,

You said:  "Part of my cynicism about compensated bridges comes from the fact that I use a capo more often than not, and have 3 longnecks, hence my favoritism for the bridge end."  I think you meant "compensated nuts" but I totally get what you're saying.  Your remarks are very much in line with my own way of thinking.  I almost included thoughts nearly identical to yours in my earlier posts I was already pretty long-winded so I left them out. 

A zero fret would solve everything, and I have no idea why banjo players are so dead-set against it. 

What Martin has done with nuts is not the shape of the nut, but an adjustment in the nut-to-first fret distance.  I am using the word "compensated" to mean that they have compensated the position, not the shape, of the nut.  Other people have used the term in the say way I have, but I think the word "relocated" would be more accurate and that's really what I should have said. 

Yes, it far better to have the first fret short because you can put a back bevel on the nut to fine tune it and I don't understand why this isn't a more common practice.  It is an easy and elegant solution and it becomes much easier to locate the contact point of the nut so it ends up in the right place. 

As a long-neck player it much less of an issue for you, not only because you generally use a capo, but even without a capo the first fret is considerable longer on your banjos but the nut height probably about the same and therefore the nut-height-to-fret-length is less as is the intonation issue. 

Anyhow, sorry if I was unclear, because I am certain that you and I are in agreement in most regards, and perhaps in all regards.   

Edited by - DantheBanjoMan on 07/24/2011 17:45:04