I Think I Messed Up--Intonation

[blowingrocknc]

Yesterday, I changed the strings on my new National tenor guitar. It is new, as opposed to vintage but new for me. I lowered the gauge a little, and the new strings sound and play much better. But, I might have changed the strings wrong. I removed all the strings, then put the news ones on. I now have a small, but somewhat noticeable intonation issue with the two base strings (tuned D and G). They go sharp around the second fret, then seem to get back towards normal by the 12th (but still a tad sharp). Anyway, what is my best course of action? Should I loosen all the strings and then see if I can slightly turn the base side of the bridge towards the tailpiece. then tighten and see if things improved. Then keep doing this until I get it right? I thought the bridge was the biscuit, which was glued to the top of the cone. Does it actually move? If so, how much can I move it around without doing damage to something? I'm totally new to resonator guitars. It is hard to get anything to reach the bridge in order to move it, as the tenor is much smaller than a regular resonator guitar, thus the metal shield over the biscuit is much smaller too. Can I just push one side of it with my little finger or with an eraser on a pencil? The intonation isn't terrible as it is right now, but it was virtually perfect when I got it from National Help! Thanks.

[snakehips]

Hi there !

Best to always change strings one at a time so the other strings keep everything in place.
If taking off all the strings, put on the middle strings first, tuning most of the way up, then the others either side.
When all syrings on, tune all up correctly.
NB. If the nut isn't glued in place, it can also shift out of position - so check that is OK too.

If you lowered the saddle slots, it may have had some degree of compensation built in to the slot - and you might have lost it - but might be able to give it back by temoving some wood under either the neck or tailpiece side of the slot.

If you can improve the intonation by turning the biscuit a little, then cool. If it needs more, I'd send it to a luthier that knows resonator guitars well.

[blowingrocknc]

Thanks for the response. I've been messing and playing this morning. It's really odd, because the strings seem to slip in and out of proper intonation. Sometimes, the intonation is very good, not excellent, but very good. Other times, it's off enough to be bothersome, then I mess around some, and it's back to being good to very good, but not excellent like it was before I changed the strings. I've got a feeling that this is just one of those ghosts that live in all musical instruments, playing games whenever they like. What the heck. I'm enjoying playing, so I should just leave it at that. The same types of things happen with my banjos and my other tenor guitar, so I guess I might be too picky sometimes rather than others. Bill.

[blowingrocknc]

Well, I guess I'm mostly just talking with myself right now, but I've spent the last hour loosening the strings, then nudging the biscuit, then tightening, then testing. Over and over again. I can see results, but it just wasn't right, until just now. I hope it sticks. For now, the intonation looks good at the 12th and at the lower and mid-fret levels as well. I really hope it stays this way. I took all the strings off when I changed strings, and I knew it wasn't a good idea, but I read something from National about taking all the strings off in order to avoid crushing a corner of the biscuit. I think they meant to just loosen them some, then alternate replacing and tightening. Whatever, I'm learning, and that's what matters. I hope Michael has a chance to comment, but I'm sure he's busy much of the time, so I don't mind waiting. Bill.

[blowingrocknc]

Ok, now that a couple of days have passed, I can say that turning the bridge/biscuit works to return proper intonation. I have also found that it only lasts for a few hours at most of playing, then I have to turn the bridge again. It seems to be slipping back to it's former orientation. This morning, I decided to get the intonation proper, then loosen the strings some, then tighten the base string first, then the high treble, then the other base, then the other treble, then fine tune them all. After doing this, intonation was just fine. I'm hoping that by tightening the bases string first will cause the entire cone to stay in place, since turning the biscuit also apparently turns the cone. I'm only talking about a slight turning, but slight is all it seems to take. I just need to get it to stay in place. Since I know nothing about resonator guitars, I'm flying by the seat of my pants here. I did read one of Michael's very old messages from several years ago, where he discussed intonation and nudging the biscuit. Using his comments, I think what I'm doing might be the right way to go about it. Fingers crossed for now.

[Michael Messer]

Hi blowingrocknc

I really think you should call the people at National and have a chat with them.

The intonation should stay in tune for decades.

With a brand new instrument from a company with a reputation as fine as theirs, they would not want you to be messing with something that could cause damage to the instrument.

Give them a call and they will sort you out.

Shine On
Michael

[blowingrocknc]

Mike, thanks for the advice. Will do. Bill.