"Backset" AC saddle?

[Greg Smith]

Hello,

I'm a non-luthier looking for a DIY solution to an intonation problem with an older Godin Multiac nylon-string guitar.

As I understand it, some older models are known to have problems with bridge and/or slot placement.

The guitar's too sharp at the 12th fret on all strings, even with lower-tension strings than the recommended ones. I haven't been able to set the breakpoint on a normal 1/8" saddle far enough back, or the action low enough for my playing style, to compensate.

I know the "right" thing to do would be to take it in to have the slot filled and re-cut. But I'm poor as a churchmouse at the moment.

I have a hare-brained idea of fashioning a saddle with a "backset," as shown in the attached picture. That would allow me to set the breakpoint further back than the back edge of the slot.

Has anyone ever done this? I realize that it will make the break angle more acute, as well as increasing the mass of the saddle and maybe even the pressure against the bridge in front of the slot. But is it a totally mad idea?

Thanks.

Greg

[Michael Breid]

Hey Greg. I like your idea of a backset saddle. My Godin Multiac was a piece of crap so I got rid of it pronto.(no tone, high frets, bad intonation, etc.) I found out later that to get the proper tone for a nylon electric I had to buy an expensive synth to run it through. I'm not recommending you get rid of your guitar because all guitars are different and you may like the sound you are getting. If you've got the tools for working a material like bone or micarta I'd say try the backset saddle. In fact, I may try that on my Martin acoustic which has slight intonation problems. It takes time to do intonation correction which is trial and error, but bad intonation hurts more than stubbing your bare toe on a table leg. Good luck, and take it slow. You might have something there.

[Russell Vance]

The backset saddle may give you enough intonation range but I would dummy up the adjustment first - This particular Godin guitar can be credited with helping me become competent and informed regarding intonation - we went through two instruments and a lot of fingerpointing before I finally quit on attempting to intonate these instruments. Rather than carve a whole new unit you can glue on a strip of bone to the back of the saddle and relieve the front of the saddle and this will help 'flatten' the whole string series. But, I recall, the intonation problem is not linear and playing octaves up around the twelfth fret was very unrewarding regardless of what was done.. Good luck with this monster. Rusty.

[Greg Smith]

Russell,

After two thumbs-down for the Multiac I'm starting to realize why I've never seen one, or any Godin, hanging in the Gryphon shop down the road, where Frank Ford does his magic.

Shucks.

Dummying up the adjustment using the current saddle sounds like a great idea. Thanks!

Greg

[Greg Smith]

Michael,

Thanks. I'm not expecting the Multiac ever to sound like my handmade Contreras CG, but I need it to play in a noisy band where an occasional nylon-like sound is needed. I've got a body-modeling box to help mellow out the pickup quack. The only pleasure I get out of playing it unplugged at home is having the upper-fret access.

Greg

[Bob Webster]

You know, I think I saw that sort of thing demoed in a Stew-Mac tech tip. Just for a start, though, the saddle should be the same distance from the 12th fret as the 12th is from the nut + 2mm to get into the ballpark of the right intonation, So..., do the measurements and you'll be able to see if you have enough back-up room to do it.

You're right that it will sharpen the break angle but there may be a solution to it since you haven't been able to get the action low enough. If you're not against doing a little surgery on the bridge itself, you could lower the top of the slot at least on the back side where the additional bone will rest. As drawn, the backset saddle is ramped to the front. It's better to have a roll off on the back side of the saddle, Given enough room to go back and down, things should work out fine, though. As long as you don't have to lower the bridge too much in front of the slot to get the right action, there shouldn't be a structural issue. Share the measurements with us when you get them.

That said, Rusty's experience with these doesn't bode well for the outcome. Intonation for classical guitars has been a topic of great interest and tooth gnashing. Greg Byers has all the equations and know-how to really set one up to sound great, but he acknowleges that it all goes out the window when you change to a different brand or style of strings.

Cheers?,
Bob

[Greg Smith]

Bob,

My drawing is pretty rough. I did intend to have a rolloff on the back side of the saddle.

I've shimmed my current saddle along the front to get it to sit up as straight as possible, to bring the breakpoint as far back as possible.

But I've read that a saddle for an under-saddle pickup should be a little thin and loose for the slot.

My current saddle was loose and tilting forward before I shimmed it (it's probably really a 3/32, not a 1/8).

I guess the backset saddle should be a little loose in the slot, too, which means it too will tilt -- so I'll have to factor that in.

Being a classical guitarist primarily, I don't gnash my teeth too much about intonation as long as it's OK below the 12th fret ;-) My main CG is pretty well intonated, to my ears.

Thanks.

Greg

[Mark Dobbins]

Greg if its playing sharp on all strings, why not pop the nut off put a shimm on the fretboard to move the nut back till the intonation is correct, you will have to sand whatever the shim is off the back of the nut,Seems easier than making a stepped saddle to me

[Bob Webster]

Mark, this is not the way to go with this problem because setting the nut back will blow the intonation of the first few frets clear out of the water. There are builders like Greg Byers who selectively set back certain strings like the G string but, even then, the setback is only on the order of ~0.15mm, or 0.6 gnat's asses.

Bob

[Greg Smith]

Mark,

Thanks for the suggestion. I've been reading about nut adjustments for intonation problems, but I don't quite follow the logic of it.

If I capo my Godin at the first fret and test the harmonics against the fretted notes at the 13th fret, the fretted notes are all sharp there, too. Ditto if I capo at the 2nd fret and test at the 14th fret.

Am I right in thinking that the capo'd fret serves as a virtual nut in a test like this? That would suggest that moving the actual nut back would only help with problems of intonation on the open strings.

Still new to this, though, so open to all suggestions.

Greg

[Bob Webster]

Greg, you have the situation figured just right. One of the subtler points, however, is that higher actions require more correction for intonation. Fretting a sky-high action introduces more incremental tension in the string, causing it to ring sharper than on a lower action where the net tension change on fretting is less. So, you might be able to kill two birds with one stone.

Could you send us a picture of the bridge? and some measurements, perhaps?

Bob

[Greg Smith]

Bob,

Can't post pictures right now, but here are some measurements:

25 3/8" string length

14/32" Eb from soundboard to bottom of string at saddle
13/32" Et " " "

3/32" Eb from 17th fret to bottom of string
~2.5/32" Et from 17th fret to bottom of string

< 1/32 from first fret to bottom of string, both strings.

No issues with fret buzz anywhere along the neck. Action feels good at this height.

Don't have a feeler gauge, just a rule with 1/32" marks. I see what looks like acceptable neck relief at both top and bottom strings.

Godin web site says Multiac Duet Nylon has a 16" radius, and I attempted to put a tiny bit of radius into the saddle when I lowered it.

Strings average about 5 cents sharp at the 12th fret.

One complicating factor: right now I've got the guitar strung with Thomastik-Infeld S-Series nickel/steel strings, .010 to .038, supposedly designed for "concert guitar". 16 lb tension on the Et string, 15 lbs on the Eb.

I put them on not only to cut through my noisy band, but also because they allowed me to lower the saddle without getting fret buzz.

I'd like to go back to the D'Addario Pro Arte hard-tension nylon strings the Godin was originally spec'd for, but I already know from trying to put some Pro Arte trebles back on that I get fret buzz with the current action.

When I first bought the Godin, used, the saddle was higher, and whoever had it before had strung it with the Thomastiks (that's how I learned they existed).

I tried restringing it with the Pro Arte hard-tensions, because that's what I was used to on my CG, but those were even sharper than the Thomastiks at the 12th fret. So I settled for some normal tension D'Addario nylon strings and lived with a slightly less noticeable sharpness at the 12th fret. I noodled around with it that way for years, but almost never "out".

I'm anticipating that when I carve a new, higher saddle, the sharpness with increase, even if I restring with the Pro Arte hard-tensions.

Thanks for your interest. Sorry for the long reply.

Greg

[Bob Webster]

Greg, can you give me the distance from the nut to the 12th fret and from the 12th fret to the saddle?

Thanks,
Bob