Replies to This Discussion

Permalink Reply by Phil Delpierre on September 8, 2009 at 3:13pm

I'm definitely picking up signals/vibrations from the headstock side ... I'm sure of that. My Piezo's are on the bass side of the bridge, and not touching the headstock. I hear the sound when it's purely acoustic, or hooked up to the amp, so it's not the piezo pickup.

Based on your suggestion, I tried muting the strings behind the slide, and the problem seems to disappear which makes sense. CRAP ... that means I need to change how I play the slide! Easier said than done! Still seems odd that it happens on some of the guitars, and not others. I'd love to find a fix.

Thanks for the Thoughts/Advice
Phil

Ted Crocker said:

Phil, I noticed on a couple of your builds the piezo looks like it's in contact with the neck. It could be that it's picking up the tones from the headstock side of of the strings vibrating the nut. Are you muting the strings behind the slide?

Try setting the slide on the strings and tapping on the nut to see if it is picking up anything.

You can try encasing the piezo in wood or hot glue and see if it's not as sensitive to direct vibrations.

Anybody else have an idea?

Ted

• ▶ Reply

Permalink Reply by Old Lowe on September 8, 2009 at 3:42pm

Yes Phil I make steels and around the 12 fret I get the exact same thing and I have been asking experts and pickers and hove got no solid answers.
But they all think it is real cool!
My theory is that the sound is going back thru the wood body and coming down the strings and making new sounds.
I can make it do it around the 9th fret and slide up the the 12th real slow ans there it is one note goes down kinda spooky!

• ▶ Reply

Permalink Reply by Roosterman on September 8, 2009 at 9:33pm

Phil, you are not alone!
The very first cbg I built suffered this same problem - to such a degree it was un-playable. If anything, the 'down' tone was over-powering the 'normal' tone.
If you play slide there is an easy solution - play with a finger muting the nut side of the strings. This should dampen that undertone.
In my case, I broke the guitar up and started again. Im not suggesting you do that, but the changes I made might help you in your next build.
Initially I built a 3 string with piezo, using an old acoustic neck sliced in half. Of course this was a bolt on job. The scale meant that the bridge was hanging over the back of the box. I thought this was the cause of the problem, as, like you, the piezo was not touching the neck. It wasnt.
So... no real answer as to what causes it, but as a solution, I swapped the neck for an thru neck with an angled headstock, corrected the scale so the bridge sat on the box, replaced the piezo with a magnetic pickup and added a tone pot - and guess what? No double tones!
I see you already use a thru neck so all I can deduce from that is.... junk the piezo!!

Sorry I cant be of more help!

• ▶ Reply

Permalink Reply by J. K. on September 8, 2009 at 10:09pm

I had the same problem on my first build. But i solved it by moving the bridge back more and it got a lot better. Then I started fiddling a little with the angle of the grooves on the nut. Don't know really what happened but the back tones disappeared.

• ▶ Reply

Permalink Reply by Will Carter on September 8, 2009 at 10:21pm

Dunno if this helps but I used to put something around the nut to lightly dampen the strings at the nut. This was only for tapping etc tho so I dont know if it will work. Rubber bands or felt etc.
Hope this helps mate

• ▶ Reply

Permalink Reply by StarGeezers on September 9, 2009 at 1:32am

Been playing lap steel for almost 50 years now ... since I was ten ... My first teacher taught me the value of muting the strings behind the slide and using palm muting at the bridge ... good muting technique can eliminate all those odd sounds/noises that plague those that don't mute ... Works Great on CBGs too... takes a little practice, feels odd at first , but WORKS !!! Well worth the time spent refining this technique...

• ▶ Reply

Permalink Reply by Phil Delpierre on September 9, 2009 at 2:42pm

As I thought about this, there are some distinct differences between the 2 CBG's with a clean sound, and the 2 with this dual tone.

The 2 clean tone CBG's both have a straight headstock with no angle. The headstock is thinner as well because I used Grover Uke Tuners with a shorter post. These CBG's also use a thinner Corian nut. The necks go through the box, and are glued all the way down the box (no gap to help the top vibrate). Both these CBG's have 1 sound hole.

For the 2 CBG's with this annoying dual tone, I did scarf joint necks. The angled headstock (10-15 degree) has wings, and is not thinned down. Used Stew Mac economy Guitar tuners. The necks also have the steel bar reinforcement that is epoxied in place. I also dadoed the neck inside the boxes so that it contacts the lid at both ends for glueing, but not in the middle. Both these CBG's have 2 sound holes.


No differences noted between chrome slide, and glass bottle slide.

Seems like all the things I did to make a higher quality CBG, didn't do much for the sound! The one thing that does work, is to mute the strings behind the slide ( I really need to practice this).

Any other thoughts would be appreciated. Thanks everyone for the ideas to date. This is perplexing!

Phil



Ted Crocker said:

Is there a difference in the nut material on the ones where it happens and those that don't? Nut slots? String angle over the nut? Headstock cap? tuning? Tuners? String gauge?

What is your slide made out of? Maybe try a different material.


Funny, but I've thought about ways to find and experiment with exactly the tones you have...

• ▶ Reply

Permalink Reply by Tres Seaver on September 10, 2009 at 3:51am

Phil Delpierre said:

Seems like all the things I did to make a higher quality CBG, didn't do much for the sound! The one thing that does work, is to mute the strings behind the slide ( I really need to practice this).

Any other thoughts would be appreciated. Thanks everyone for the ideas to date. This is perplexing!

I hear the extra tones near the "harmonic" frets when playing slide on my
Martin flattop: I think the "duller" acoustic qualities of the glued-down
necks may be suppressing them a bit.

For some songs, the doubled effect is actually desirable (e.g., it sounds
pretty good when making a "long" slide up to the octave); for others, I just
mute behind.

• ▶ Reply