Moveable wolftone

[frankhond]

Hi all, I have a funny thing with my A25 which i would greatly appreciate to have explained by someone who understands guitar physics.

When putting on a capo on the 4th fret in DADGAD there appears a dead spot on the 6th (low) string 5 frets up from the capo. This is a fretted note that is fine without the capo, but becomes dead (sustain decreases dramatically) when I put on the capo. When I move capo to 5th fret, dead note disappears, instead it seems to relocate to 5th string 7 frets from capo.

Now how can a fretted dead note appear and move like this with the capo? I am fretting it at the same place irregardless of capo position (the absolute position on fretboard doesnt change), it is not an open note, but the capo seems to affect it anyway.

[singlereed]

Might just be a dodgy string - it can happen.

[Jimbo]

Make sure the capo is nice and tight on the problem string. If you're using a capo with the wrong curve or not tight enough this can happen.

[frankhond]

Actually I'm using a shubb. And it seems a little "short", the A25 seems to have a wide neck. I tried a shubb 12 string capo which is "long enough " but doesn't fit optimally. Any recommendations on a good capo?

[Jimbo]

I use a shubb too, and I've never had a problem with it. I've also got a G7th capo that lots of people like - I find it a bit heavy and bulky but I think it is fractionally longer. Try moving the capo as far over the bass strings as it will go, leaving the top e uncapoed if necessary and see if that solves your problem.

EDIT: you mention that it happens when you tune to DADGAD. Does it happen in other tunings as well?

[singlereed]

Yeah, Shubb capos are essential kit. Make sure you have the right one as they come in 3 or 4 different profiles for 12 string, std steel string etc.

[frankhond]

Ok, I have changed strings and fiddled around a bit. I get mixed results, with some capo positions the dead spot disappears, with other it comes back. The shubb is the regular 6 steel string version (with a slight rounded profile) and should be correct (or is the classical version more appropriate for A25?). I tried a few other tunings (standard, dgdgcd) as well. My conclusion is that the capo alters the neck response somehow, perhaps by adding weight - the capo is solid steel. Would be interesting to try a lightweight capo.

The guitar had another problem when I got it - the b string was much louder than the rest - but I tightened the truss rod, and the problem went away (it came with a totally loose truss rod, the guy probably didnt know there was one behind that brace). So maybe it's just that the guitar is very responsive to any irregularities, including a capo in some positions. Actually I have no idea what I'm talking about at this point. I guess I'll avoid 4th fret capo for certain songs that require a certain note...the guitar plays great otherwise and guitars are living things after all.

Are there other "optimizations" besides tightening the truss? Would the shims under the bridge affect response? I could remove them and have a a new saddle made by a pro...

[Jimbo]

I wouldn't have thought the shim under the bridge would cause this problem, nor a heavy capo actually. You could try and get someone to fret the strings where you would normally put the capo and then try the dodgy note to see if it is an issue with the capo. You're certainly using the right capo profile as it is.

The only other thing I can recommend is to have your guitar set up by a luthier that knows what they're doing. Could there be a high fret that's just touching the string and deadening it fractionally without causing a buzz?

[frankhond]

You are right, I will have someone look at the guitar. It's not that it is unplayable or anything, but "night fishing" by Simon Fox happens to sound just lovely with the capo on 4th fret. Unfortunately the tune keeps coming back to that dead note on the 6th string... I'll use 5th fret capo in the meanwhile