Adjusting intonation with string weight

[kww]

My tenor has a slight intonation problem on the C string. It sharps as you fret, generally between 5 and 10 cents. If I tune that string to C#, the intonation becomes nearly perfect, within a couple cents on all frets.

If I understand the theory correctly, that means that my bridge is properly intonated for a higher tension string, and if I increase my string weight from .032 phosphor bronze to .034 phosphor bronze, I should be able to improve the intonation. Right? Or is there a better or different possibility? Strings are always international orders away, so if I need to experiment, I'd like to order a complete set of likely candidates.

Looking at a pin-bridge design really makes me wish that tenor guitars came with a floating bridge. I guess that they would call that a 4-string mandola.

[mandolooter]

Looking at a pin-bridge design really makes me wish that tenor guitars came with a floating bridge. I guess that they would call that a 4-string mandola.

nope...here's my Regal tenor from the early half of 1900.

[Nick Triesch]

The thing is no string instrument is perfect. Some of the tuner manuals even will tell you that. One of our high end guitar shop repairman here in San Diego told me once that mandolins are really a strange little beast and they will be off a bit most of the time. You can buy some of the best mandolins in the world and when you fret open notes and then play the same note up the neck on a different string, most of the time it will be a little off. Fiddle players make up for it buy playing the note a little up or down. Just the way it is. It could just drive you crazy!!!!!!! Nick

[kww]

I know not to expect perfection. I would love to hear from someone able to confirm my basic understanding that thicker string == higher tension == less tension differential when fretted == less sharping.

[Fretbear]

You could (or have someone else) intonate the saddle a little by filing an angled ramp under the C string. If you need more or less than that would give you, you could add a small piece of auxiliary saddle material for that string just behind or in front of the existing saddle. It doesn't have to be slotted into the bridge, it can just sit on top of the bridge wood, tight against the original saddle. You can use a headless nail or knitting needle or something similar to experiment with. The new piece has to be a tiny bit higher than the existing saddle so that the string clears the old saddle.
Considering that your C is fretting sharp and using the FLAT rule (Fretted (note) Low, Away from Tailpiece) you need your C string's saddle contact point to be further away from the peghead, so you could try putting the new saddle segment behind the existing saddle, towards the endpin.
I have effectively tweaked the intonation on flattop guitars using this method.

[clarksavage]

What Fretbear said. I've done my own custom intonation on several guitars and mandolins with bone saddles. I pick up some sort of saddle blank and use my favorite carving knife to work the top edges to adjust the intonation to my preferred strings. The radius is the hard part, I have to adjust that with special care. As has been said, it still isn't perfect by any means, but I get it about "good enough" for my ears and playing style. If you're driving through the central coast of California, stop by and we'll whittle one up on my back porch!

Clark

[epicentre]

The A string on my IV F5 conversion was intonating just a tad sharp with J75's. Put on .017's on the A,(after moving the bridge around, etc.) and it's maybe just half a tad now.... , if that makes sense. (Sounds better also) But, as I go up the neck, it's right on D on #5 fret and so on up. go figure............you might be on to something, KWW.

Loud and barky after the conversion. Gotta love it.

Working on a new maple adjustable bridge and will get the A "in" first, then worry about the rest of the slots.

[Phil Goodson]

All good advice for the problem at hand, ....

but back to the original question (for the sake of intellectual stimulation): Will heavier strings make the unwanted "sharping" of fretted notes better?

I would have predicted the opposite. That a lower tension would mean less force to push the string down to the fret and therefore less stretching (actually, less increase in tension) of the string, (whew), and therefore less tendency to produce poorly intoned (too sharp) notes.

Am I thinking backwards? Or backing thinkwards?

[John Flynn]

Here is a quote from Roger Simonoff's "The Luthier's Handbook."

Heavier gauges of strings note sharper (higher pitch) than lighter gauges at the same fret. The difference is the result of the heavier guages not stretching as easily as the lighter gauges.

So it would seem that a lighter, not a heavier, string would help in your situation. Also, as has been mentioned, it would not be that hard to take a small file and notch the saddle at about a 45 degree angle on the front (playing) side at the contact point of that string. This will simultaneously do two things: It will move the contact point slightly away from the nut, and it will lower the string slightly. Both will cause the string to note at a lower pitch. Be careful and go a little at a time, though or you might get buzzing.

[kww]

I guess I'll go in armed with a few light strings first. One of the problems with living in an isolated area is that there isn't any help available if I muck it up. Tends to make me want to fix things with string tensions as opposed to files and saws if I can. Cutting a new saddle isn't beyond my capabilities, though, so if I have to, I have to.

[dave17120]

"If I understand the theory correctly, that means that my bridge is properly intonated for a higher tension string"

As far as I understand it, a piece of wire vibrates at a given frequency, at a given tension, over a given distance.
The thickness of the wire allows us to get a variety of notes over that given distance.

If you use a thicker string, you will just need more tension to bring it up to your C, which should make it harder to play. If you use a light er string, you will need less tension, but this would only fix the problem if it was caused by fretting pressure.

The problem apparently with strings, is that the thickness tends to inhibit vibration, so when we have a perfect length and tension, the thickness throws the note out a shade. Of course with all the strings being of different thicknesses, they all get thrown out a little differently.......... hence the need for compensated saddles, which go some way to resolving the length issue.

You could spend hours and loads of money trying different sets of strings, and not solve the problem, for the reasons above. Have fun and learn a lot more about adapting the sound of the instrument.... buy a few saddle blanks and try out some saddle compensation. That is of course if the saddle can be removed..... a photo would help.

There are lots of folk here who know about compensation and can support your efforts. If it doesn't work, you still have your old saddle! Dave

[jharr]

You might try lower action at the nut. If your strings are much over E.006, A.008, D.010, G.012 over the first fret you may get some sharpness at the first few frets due to string stretch. Make sure your bridge and relief is set correct before you setup that low.
#J
I reread your first post and saw you were refering to a Tenor instead of a Mandolin. You may not go that low on a Tenor, but high setup can still cause sharpness on any freted instrument,on the first few frets.
J

[Paul Hostetter]

Strings don't cost very much. Rather than speculating about it and pondering various cockeyed and well-meant theories online, why not just try some different gauges and see what happens? Waiting for someone to confirm an idea in words seems like such a waste of time when all you want is an instrument that plays in tune.

You can have any string gauge you want and have it play in tune with not much effort. Moving a saddle in a pin bridge is not exactly rocket science.

[kww]

The order for a set of .030, .032, and .034 strings in various materials is going in today. The strings aren't much. It's the shipping and import duties that kill.

[kww]

My care package from juststrings.com arrived, and the answer is that moving from a .032PB to a .034SS fixed it, and the extra tension helps with playability as well.