Intonation Advice

chrisoldroyd

i have a few questions on setting up intonation and looking for some advice from you guitar gurus.

1. What’s acceptable in cents between open string and fretted 12th for correct intonation?

2. Should I use harmonic at 12th rather than fretted to intonate?

3. After intonating why would it change and be a few cents out after completing other strings?

4. I am using the Peterson’s Istrobe app on my iPhone with the input cable, is this accurate enough or should I buy a better tuner?

As always advice appreciated 

Cheers

Chris

pintspiller

It's 12 fret note vs harmonic at 12 fret that you use to intimate and they need to be as spot on as you can get.

I can't see an app on a phone being accurate enough. But I stand to be corrected.

guitars4you

you can use the 12th fret harmonic or the open string - same note effectively - This is your correct note as such - Then play the 12th fret note and adjust accordingly until it is the same note as the harmonic/open string

Not sure what guitar you have - Some guitars like a Strat and you might need to lower the pick-ups, as pole pieces tend to have an impact on the 12th fret note, from magnet pull

I've never used a mobile app so can't comment, but any good tuner should be fine - I can get pretty close with my ear most of the time

I often then check the fretted note at the 19th fret as well - if it is there or nearly there at the 19th fret regarding intonation, then almost certainly in at the 12th

Other factors can have an input into the actual set-up and intonation - sensible relief, sensible action and a well cut nut plus as I mentioned the pick-ups can cause issues regarding intonation 

Corvus

I fret at the 12th with normal finger pressure, so it matches actual playing best as poss. Then check higher and lower frets.

Check relief first. Too much and fret around 5,7 etc can go sharp.

If you're using light pressure to adjust, chances are you press harder in playing, making it sharper.

ICBM

1. Ideally, zero.

2. It shouldn't make any difference - the harmonic should always be perfectly in tune with the open note - but pickup magnets (especially on a Strat) can do odd things if they're adjusted too close to the string.

3. It shouldn't, unless the whole bridge is moving.

4. A phone app is easily accurate enough. You can make more difference just by changing your fretting pressure.

I use the TC Polytune app on my phone just via the phone mic. (Although I also check by ear using harmonics vs. fretted notes at other positions than the 12th.)

guitars4you

valid point from both @ICBM and @Corvus regarding light touch on the 12th fret - squeeze the fretted note to much and it will instantly go sharp giving you a false note to tune against the open/harmonic

crunchman

guitars4you said:

valid point from both @ICBM and @Corvus regarding light touch on the 12th fret - squeeze the fretted note to much and it will instantly go sharp giving you a false note to tune against the open/harmonic

The problem is that most of us will probably fret the note with more pressure when playing it for real.

You need to try to fret the note with the same pressure you would use when playing.  If you are just using a light touch when doing intonation, I wonder whether you would be better setting it so the fretted note is fractionally flat.

guitars4you

crunchman said:

guitars4you said:

valid point from both @ICBM and @Corvus regarding light touch on the 12th fret - squeeze the fretted note to much and it will instantly go sharp giving you a false note to tune against the open/harmonic

The problem is that most of us will probably fret the note with more pressure when playing it for real.

You need to try to fret the note with the same pressure you would use when playing.  If you are just using a light touch when doing intonation, I wonder whether you would be better setting it so the fretted note is fractionally flat.

granted at times I've set it up so it is okay, yet found maybe a touch sharp to the player, so yes fine tune to suit (no pun intended)

flying_pie

I would always set up a guitar as I play. That means fretting and pick the strings relatively aggressively for the most part. 

I try to get no difference between 12 fret and open but don't worry if it's within a couple of cents as the human ear can't detect that little difference 

Funkfingers

chrisoldroyd said:

3. After intonating why would it change and be a few cents out after completing other strings?

Are you adjusting the intonation with the guitar held in your normal playing position or laid flat on a bench?

Does the guitar that you are adjusting have a vibrato bridge?

chrisoldroyd

No, I have been adjusting it in the playing position. Its an SG so has a tunamatic bridge. 

I think I am there now its definitely much better than it was so fingers crossed.

Cols

One final thing to add to all of the excellent advice above; when setting intonation, make sure you do it after putting on a fresh set of strings and allowing them to settle in.

Welcome to the forum!

guitars4you

Cols said:

One final thing to add to all of the excellent advice above; when setting intonation, make sure you do it after putting on a fresh set of strings and allowing them to settle in.

Welcome to the forum!

so true - just dawned on me that I do so many of these things all the time, by instinct, that you forget to pass on to others what is natural for you - so valid point from me on that

chrisoldroyd

Thanks everyone for the comments, great to know you all have my back in this great community

viz

Absolutely re. old strings - they suffer something called inharmonicity where the harmonic octave isn’t a true octave above the root. 

You may not need a tuner for checking intonation - your ear should be just as good if not better for detecting whether the fretted is flatter or sharper than the harmonic. 

bacchanalian

chrisoldroyd said:

Thanks everyone for the comments, great to know you all have my back in this great community

Welcome! It is the beginning of a voyage of discovery.

I recently bought a strobe tuner and am really liking having the intonation spot on and then using a sweetened tuning like James Taylor's.  Seems to sound more in tune but with the warm weather it does not last.