New mandolin setup to fix inconsistent intonation along a string

I just got my first mandolin in the mail, an Ibanez M510 (A-Style) bought at a moderate discount due to a supposed factory blemish (which I haven't even been able to find). Based on discussion I found of these and the seller's picture which still showed foam under the bridge, I was expecting to have to set it up completely myself and replace rusty strings, etc.

When it came, though, it was tuned quite low but it seems some setup was done before it left the shop. Strings look in decent shape yet too. Intonation on the middle strings is great, a tad flat on the E string octave — but the G string is a little bonkers!

With the open strings tuned up, a basic 0-0-2-3 G chord sounds alright… but when I play a D chord on 2-0-0-2 it's really gross.

According to the Cleartune app on my phone, the G course is about 15 cents flat at the twelfth fret. That's not great, but as used in that chord those same G strings are actually over 10 cents *sharp* at the second fret. This is an easy chord, and I'm fairly certain I'm not bending it. (Any less pressure and it mutes/buzzes — new to mandolin but been playing guitar/bass/uke much longer.)

What would cause this inconsistent intonation? It's gradually less sharp until about the 5th fret, and then starts going flat up to the 12th. Action is not crazy high especially back at the second fret, but looks like there's room to lower it if need be. The bridge is a compensated one, bit longer for the G and A than for the D and E. I've noticed it's not perfectly perpendicular to the strings either, a bit slanted so that the G course gets more length than the A. What should my next steps be?

Mandolins are fussier than guitars because the short scale exaggerates all issues. Leaving the thicker G strings high yields a strong tone when strummed open, probably a sales habit.

If the string height at the nut is high it will play sharp on the first few frets. (Bridge placement is more noticeable in the higher frets.) It would nice if it was perfect from the start but it's common, I think, for the slots to be on the high side, because too low is unplayable. A visual test is to hold the G strings down on the first fret and watch the deflection when you fret the 2nd. Then watch the deflection from open string to the first fret. It should be similar, perhaps just a bit greater than between frets.

You can pay for some slot filing at a shop or buy a sized nut file for a few bucks (StewMac). The risk is going too far but that can usually be fixed by filling the too-deep slot with crazy glue, and after letting it cure overnight file it again.

Another possible but less likely issue is the fingerboard may be a smidge too long, in which case lower nut height will not help. This can be tested if the slot is quite low, by using a good strobe tuner to compare the individual fret behavior. Shortening the fingerboard slightly allows a higher nut and stronger tone. I did this on my instruments, which really needed it. I leave the low string pair rather high and it sounds great and plays well in tune on all frets.

PM Rob Meldrum and get his setup book. Many answers to your questions.

Try some new strings, I have had bad strings intonate weird

Are the G strings riding dead on the front (fingerboard) side of the nut. If not you are in effect noting more than one fret at the first fret. As stated this would be more noticeable at the nut end and would sotr of even out by the 12 th fret.

Fret the G strings at the front side of the second fret and then look at the clearance over the 1st fret. It shouldn't be more than a few thousandths. If it is, it's too high. This will make it sharp when fretted near the nut. Check the other strings as well. The E strings should be real close to touching (you should not be able to see a gap). Once the nut is set correctly, then you adjust the relief in the neck, then the bridge height, and finally move the bridge for intonation. These last two go hand in hand. All of these will effect intonation.

Even with the setup perfect there will be some compromise.

You might try a new set of good quality strings before you freak over this issue. Even the best instruments usually come with strings that are, shall we say lacking (ususlly just good enough to show that you can actually put strings on it), and your mandolin probably came with a lesser grade set regardless of how shiny they are.

I agree with Roger, put on a new set of good quality strings. Even then I have had (rarely) a poorly wrapped G or D string that does what you describe. You could experiment with the G corse only if you wanted...

Billy

billypackardmandolin.com

The electric version was my first mandolin but I bought it used. It appeared "well played" and I used Rob's ebook to great advantage. However I did have decades of guitar setup experience so after you read it over and you do not feel up to it, check around your town for a shop that can do the setup. Along with a fresh set of strings. And it is ok to go a step lighter on strings if you are just starting mandolin. You can always move up when your fingies get stronger.

As the others noted, I happily provide my ebook for free. Please email me at rob.meldrum@gmail.com and put Mandolin Setup in the subject line. Please don't PM me here, it's so much easier to reply to an email request.

I think you'll find that after properly filing the nut slots (with the low-cost nut files I show you how to make) and adjusting the height of the bridge/saddle your mandolin will sound a lot better!

Rob

Thanks all! Per Tom's post, I think the nut height is a likely culprit as there is much more deflection to the first fret than when adding on subsequent fingers. I've bought a set of cheap needle files (which look exactly like the cheap sets of "nut files" that go for an extra few bucks) and emailed Rob for his book before I actually go at it. And while I'm getting all the strings out of the way anyway I'll go ahead put on the fresh strings I have in hand.

In the meantime it's been settling in a bit already, or at least my ear is getting more sympathetic to the "coloring". Been fun learning new chord shapes [well some of them anyway… you might see more posts from me on that!], almost a competition between me and my violinist wife as to who can make the most progress each day :-)

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Originally Posted by Rob Meldrum

As the others noted, I happily provide my ebook for free. Please email me at rob.meldrum@gmail.com and put Mandolin Setup in the subject line. Please don't PM me here, it's so much easier to reply to an email request.

I think you'll find that after properly filing the nut slots (with the low-cost nut files I show you how to make) and adjusting the height of the bridge/saddle your mandolin will sound a lot better!

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Rob, I greatly appreciate the PDF you sent me. It was very helpful and confidence-inspiring.

While I haven't fully finished dialing in the normal 12th-fret intonation [got sidetracked by a recalcitrant E string that I trimmed to "size" too early], the action is now much better. Somewhat surprisingly, the nut slot for the off-tune G course required the least depth adjustment of them all. It was the saddle that needed the most height reduction, both in terms of sanding and then lowering the thumbscrews from how it arrived.

You can be amazed at how high strings can be at the nut, how poorly a bridge can be fit, and how high frets can be at the neck joint on new instruments. But they cost what they do because the extra two hours labor is bypassed.