12-string bridge buzz

[Jim Chelsvig]

Hi all.  I'm new here so my apologies if this topic has already been discussed.  I have a 12-string with buzzing from the bridge on the B and G (primarily the octave) strings  High E's, D octave and all other wound strings are fine.  I've been through Frank's buzz diagnosis, looked at everything and made some corrections as needed.  Buzz occurs on open and fretted strings at all frets.  Action is still a little high on treble side but shouldn't be an issue.  Buzz happens when cleanly fretting single notes.  Strings are .012-.053 tuned down a step.  I raised it a half step thinking there might not be enough tension on the individual strings.  Still the same.  Could the paired strings be hitting each other?  String spacing at the nut is 5/64 in. and at the saddle 9/64 in.

 

Here's one I just thought of - in many cases the second string of the pair makes pretty solid contact with the pair's first string bridge pin.  Being behind the saddle I wouldn't expect this to be an issue but what do I know?  Any advice, suggestions, or even ridicule would be appreciated.  Thanks.  Oh yeah, I built this one so I have no one else to blame.

[Jeff Highland]

What is the break angle over the saddle on those strings like?
Does the saddle profile have a distinct break point or is it flat?

[Jim Chelsvig]

Hi Jeff,
Saddle is not flat. I've got well-defined break points and the strings are supported on the back side of the saddle with a rounded off slope. I ramped the slots for the octaves as per Frank's instructions so their break angles are more than adequate. The tonics were already fine. I printed out Frank's buzz diagnosis and all of the pertinent how-to articles focusing on noise from the bridge. I went through it step-by-step checking, and when necessary correcting, everything I could. Even checked some things that weren't included in the bridge section. That doesn't mean I did everything right but I think I did. As far as I know the only thing I haven't tried is a hammer. But I've thought about it. Thanks for checking in.

[Tim Mace]

Sounds can also be caused at the nut if a certain string has no break angle,,,sometimes this can be eliminated by making sure the string is started at the top of tuner post and sufficiently wound down to the bottom creating more angle.Tuners themselves can also create probs if any looseness from screws or buttons exist.Or action may be too low.Are you positive it's at the bridge?

[Jim Chelsvig]

Hi Tim,
Well, my left ear is the good one and I'm hearing all the noise in my right ear so I gotta believe it's at the bridge. I believe the break at the nut is good and that the tuners are tight but I'll double check to be sure. I have a couple other things I want to check and will include the nut and tuners. Can't do anything until tomorrow night but I'll report back on whatever I find even if it's nothing. Thanks for the suggestions. Keep'em coming...