Intonation Question

[TheShreddinHand]

Ok guys, before you tell me to call customer service , hear me out. I have one of my 7s in standard tuning with a 56 as my low B and my other seven string in Drop A. In order to match the tension on the B string by going down to A, I use a 62 gauge string (the tension matches the B with a 56). But, the intonation was definitely off (fretted note being sharp when matched with harmonic at the 12th fret). So, I moved the saddle back and kept moving it back until I've got them to match and now my chugging chords sound great! However, as you continue to fret that Low A up past the 12th fret it starts to go sharper. Now I don't really plan on playing chords on that low A much past the 12th fret so it's really not an issue, but I just feel like I moved the saddle really far back already at this point (especially compared to my standard tuned 7). Is there such a thing as moving it too far back? Should I keep going till my 19th fret harmonic and fretted note match?

For what it's worth all 6 other strings are perfect at the 12th and 19th fret respectively and yes, bridge is flush, neck straight, etc.

-Eric

 

[Roubster]

Adjust it until the whole string is intonated from the the first fret to the 24th. Dont forget to check the intonation on the 24th fret as well (harmonic as well). I'm sure you will be able to do this just fine with the compensated nut and as long as you can still go farther back with the saddle.

 

[TheShreddinHand]

Adjust it until the whole string is intonated from the the first fret to the 24th. Dont forget to check the intonation on the 24th fret as well (harmonic as well). I'm sure you will be able to do this just fine with the compensated nut and as long as you can still go farther back with the saddle.

Ok cool, there's plenty of room to keep going back, I just felt like I had already gone pretty far ya know! And when I eyeball to my other guitar I got worried. Oh well. And to answer everyone's question....Yes, the JP7 is BRUTAL in Drop A!!

-Eric

 

[RocketRalf]

Don't check the 19th fret. On an equal tempered instrument like the modern guitar (ideally), not every fretted note is meant to match the respective harmonic. Only check the 12th and the 24th frets for intonation.

 

[littlephil]

Don't check the 19th fret. On an equal tempered instrument like the modern guitar (ideally), not every fretted note is meant to match the respective harmonic. Only check the 12th and the 24th frets for intonation.

The 12th is probably the most important to get intonated correctly, but it isn't always the most accurate. Once you've got the 12th set, you should compare it at a few points across the neck (I use the 5th and 17th frets) as it helps to make sure the intonation is good across the whole neck, and its very possible that even if the 12th is good, the 24th still may not be perfect.

 

[RocketRalf]

This might prove interesting to someone: Here's a table showing the differences between just intervals (harmonics of an open string for example) and the equal tempered intervals (fretted notes). Look at the far right of the table, there you'll see the difference in cents of a half-step:

Equal temperament - Wikipedia, the free encyclopedia

 

[DrKev]

Yes, Ralf is indeed correct. What that scary lookin' table shows shows is the 19th fretted note and the 19th harmonic shouldn't match. The 19th fret harmonic (and the 7th fret harmonic) is an octave + perfect 5th above open string. That will be 2 cents sharp of the fretted note. You'll need an accurate tuner to see that (many tuners are only accurate to 3 cents, some really cheap ones maybe even worse).

Of course, it really matters to those of you with dog ears instead of human ears and who can fret every single note they ever play with exactly the same pressure and accuracy in finger placement. For the rest of us, we shouldn't lose any sleep over it.

Standard 12th fret vs it's harmonic will do just fine. In equal temperament tuning the only interval that is 'perfect' is the octave. So, you can also use any two fretted notes that are 12 frets apart (e.g. 3 and 15). If you have a 24th fret, you could also check that against it's harmonic.

I emailed customer service earlier today and suggested they remove the 19th fret stuff from the intonation FAQ.

The bottom line (three, actually) - if your guitar sounds good and you are happy with it, don't worry about it. It's all to easy to drive yerself crazy chasing things like this when you don't need to. There is a lot to be said for "close enough for rock'n'roll".

 

[TheShreddinHand]

Sweet, thanks for all the info guys! Good stuff!

-Eric

 

[Spudmurphy]

I seem to remember Dan Erlewine talking about setting intonation depending on the attack of the note. - in other words depending on how hard you play the note this is a link to some other useful info

 

[DrKev]

Yes spud, that seems perfectly sensible! And reminds me...

When setting intonation, do it in your normal playing position. Laying a guitar on a table makes some adjustments nice and easy but gravity makes a difference and most of us don't play the guitar laying on it's back.

The same applies when tuning. Try it! Using a tuner, tune the guitar lying on it's back. Now, sit down and hold the guitar in your normal playing position and check the tuning again. Obvious difference (particularly so with a floating trem)! Now re-tune the guitar, then put the guitar on your strap and stand up with the guitar. Check tuning now. Different again! Now re-tune again and put the guitar back on the table. (You know how this goes...)

I particularly like Jack Endino's article, which contains a nice blend of experience, common sense, and pragmatism where tuning is concerned but he looks at intonation too.