Intonation OFF with compensated nut - what is wrong?

[Stefanowitsch]

Hello!

I used to own several Music Man JP6 models but all send them back. I could not get one single chord to play in "tune". I have the feeling that the compensated nut is causing nothing but trouble.
Can you guys explain this to me?

To get things clear:
When I am setting up the guitar I use fresh strings, the action and the neck relief are set perfectly correct.
I intonate the guitar with the note at the 12th fret against the open string. Business as usual, right?

Now watch this:

When I am fretting a note at the first frets (1-3) it is FLAT (about -10/-20 cent). I think think this is because of the compensated nut. Usually on a normal guitar the notes on the first frets go slightly sharp.
However also the notes at the end of the fretboard are not correct aswell. Beyond the 12th fret they go flat, too. The note at the 24th fret is really off.

Another Problem:
What happens when I play for example an A-/D-/E-Powerchord on the first frets?
Here I use a combination of open strings (E/A/D) WITH the frettet notes below.
And now this happens:
The open string obviously goes slightly sharp because of the hard pick attack (we are playing metal) and the frettet notes go flat -> it sounds just horrible! Totaly out of tune.

This cant be so complicated. But since this happend on every JP6 guitar I tried I must seem to misunderstand a thing or too. I am playing guitar for almost 20 yeras and never ever had a problem like this on a "non-compensated-nut" guitar.

Can you help me out on this?

 

[DrKev]

Welcome to the forum!

First - what tuner are you using? If it has cool funky settings on it, is it set to equal temperament tuning?
Second - never tune or test/set intonation with the guitar lying on it's back. Always do it your normal playing position.

Resources... Search for Guild of American Luthiers Data sheet #45, and Jack Endino's blog posts called "Tuning Nightmares"

 

[Stefanowitsch]

TC Electronics Polytune or the build in tuner in my Kemper Amp. Set to 440 Hz.

 

[DrKev]

A quick search of the Kemper forums shows a few people with KPA tuner problems going back quite a few years (usually it doesn't agree well with other tuners). As of December 2017, there was a known issue and Kemper were working on it. I don;t know iof it ever was resolved.

The first TC polytune is a good tuner but at best is only accurate to +/1 cent. I wouldn't use it for intonation (alothough it will do you better than say a TU-2) but I would use PolyTune 2 or 3 in strobe mode, for setting intonation. I also use the Peterson Strobe Tuner App on my phone, which is excellent.

Anyway...

Let me think about your problem and see what I can come up with.

For most people Music Man guitars tune great and many of us on the forum will never go back to uncompensated nuts. (My old strat, the G# on the low E string would play so sharp I would wince in pain). For your guitars to all be as much as 10 cents flat would be very, very odd.

By the way, how are you getting that 10 cent figure?

 

[Stefanowitsch]

I wouldn't go so far an blame the tuners. I own few guitars, most of them with a floyd rose and they intonate better than the JP6 did.
I had to send the guitar back to the guitar store because of that. Which kinda sucks because playability and sound were great and I really wanted to keep it.

At the 12th fret the fretted (and harmonic) notes were picture perfect. But by moving down/up on the fretboard the notes began to get flatter. That's something I never experienced before. Even my cheaper guitars (with a normal nut) have most of the notes just spot-on.

 

[DrKev]

Please don't think I'm looking to direct the blame elsewhere. I'm trying to eliminate the obvious possibilities here.

The compensated nut has been on Music Man instruments since 2005. They are one of the top rated brands out there, for a good reason. If there was problem with how they spaced their frets or something design wise with the nut, they'd have figured it out a long time ago. And so would their signature artists and all the other top artists who ever played them, and us here on the forum.

The probability that this happens on every JP6 you tried but nobody else noticed this has got to be pretty slim.

I'm trying to help.

 

[Stefanowitsch]

I appreciate it! I tried two JP6 models to be honest. Both with the actual specs. And on both i (personally) had problems with the intonation (especially when playing these powerchords with open strings).

And what you describe is exactly the point: Why does everybody on earth gets along with this guitar but not me? ;-)

I'd love to order another one to give it a last try. There is no music store nearby that has them in stock so its kind of hard to try a different models.

 

[coolhandluc]

It's definitely a setup issue. My tech doesn't like compensated nuts, and when he set up my MM I struggle just like the OP with intonation. He setup my strat build with a regular nut and it's spot on perfect. I think there are tricks to the setup of a compensated nut that make it intonate better. I'm just not 100% sure what that is other than using true temperament tuning. So far when my luthier said there are "trade offs" when using any style nut, I have to agree with him.

 

[DrKev]

I just did a test with my Silhouette Special and the Peterson strobe tuner app. It is impossible to for me adjust the saddles, on either the low E string or high E string, in such a way as to make the frets 1 to 5 on the neck play 10 cents flat. (I could get to -8 cents on the low E string, but that was an extreme, obviously wrong place to set the saddle). 10 to 20 cents flat is out of the question.

Also, it is impossible to have both high and low frets measuring flat if the 12th fret measures correctly. It is not something a correctly behaving physically realistic string should ever do (speaking as a PhD physicist). Maybe of the pickups were set way way too high but that would be obvious too.

So, you see why I'm putting money on some other issue/s here?

Also, speaking from experience as scientists/engineer/guitar tech, when something clearly obviously seems weird, always eliminate all the silly, obvious possibilities first. 90% of the time, that's the answer, even for the most experienced people.

Also also, I have never seen any guitar ever play perfectly in tune up and down the neck. It's always a compromise between string stiffness and tension, nut neight, neck relief, theoretical fret positions, pickups magnet pull, finger palcement and pressure, it just can't happen. There are always a few cents drift here and there, sometimes from fret to fret.

And remember that pianos have some of the same issues too - a well tuned piano uses a stretched tuning or it will sound out of tune with itself. The low keys can be as much as 30 cents flat relative to middle C. (Doing that on guitars doesn't work because we have frets, not strings for each individual note).

And that before we even talk about temperament, i.e. how many different ways are there to divide the octave? What are the "correct" frequency for a given note?

 

[Stefanowitsch]

Yeah that makes absolutely sense. I have no explanation for this phenomenon.

I can't recall exactly how much cents the notes were off. I may have gone too far by saying 20 cent. But the notes WERE off more than they should be.

Let's close this topic for now. If I encounter this whole problem once more in the near future I will come back to it and maybe we can address it further. Thank you!

 

[DrKev]

Any time!

 

[jones4tone]

I did not know the origin of the Dr in DrKev's handle. Noted!

 

[Steve Nukather]

I'm having the same problem with my L3 and Peterson VS-1. When open string and 12th fret measure in tune, frets 1-7 all measure flat.