One way of adjusting the intonation of a guitar is to tune a given open string to the correct pitch, then press the 12th fret, pluck, and see if the pitch is exactly double. If it is a bit sharp or flat then the wedge or similar at the bridge end of the string is adjusted back or forth a little, then tune the open string to correct pitch again, then 12th fret and check for double pitch again... A lot of fiddling around retuning the open string every time.
What I would like to see is set the open string to nominally correct pitch then use that pitch as a reference to check for double because every time you adjust the bridge you also affect the open string. It would be good if you could pluck open, then pluck 12th, and if it is off then adjust the bridge and pluck open straight away again without having to first reset it. We are only looking for an exact 1:2 pitch ratio - not necessarily exact pitch at this stage. When it is finally adjusted right, if open string is right then 12th fret will also be right.
Is there an app that will do this - listen for a reference pitch, as well as have the normal absolute pitches built in? Maybe it's an idea for a new app?
What I would like to see is set the open string to nominally correct pitch then use that pitch as a reference to check for double because every time you adjust the bridge you also affect the open string. It would be good if you could pluck open, then pluck 12th, and if it is off then adjust the bridge and pluck open straight away again without having to first reset it. We are only looking for an exact 1:2 pitch ratio - not necessarily exact pitch at this stage. When it is finally adjusted right, if open string is right then 12th fret will also be right.
Is there an app that will do this - listen for a reference pitch, as well as have the normal absolute pitches built in? Maybe it's an idea for a new app?
app as in an app for your Android phone?
Maybe something like this..
BOSS Tuner - Apps on Google Play
edit: perhaps should add this one too.
10 best guitar tuner apps for Android! - Android Authority
Maybe something like this..
BOSS Tuner - Apps on Google Play
edit: perhaps should add this one too.
10 best guitar tuner apps for Android! - Android Authority
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Pluck the open string, then touch it at the 12th fret lightly, but don't press it down. Now it will sound one octave higher. Then press it down, pluck again and compare.
Master Guitar Tuner (from NETIGEN Music Tuners) is simple and accurate.
Master Guitar Tuner (from NETIGEN Music Tuners) is simple and accurate.
An ordinary tuner or tuning app does that. If you tune the open string to pitch, high E string for example, then your tuner will tell you when you are on pitch. Now pluck the 12th fret. It should also be on pitch. Nothing special about it, your octave up is still an E. Your tuner has no trouble tuning both low E and high E strings, does it?
Using the open string as the reference forgets that as you adjust the bridge, that changes the open string tuning as well. When you adjust your saddles, you are tuning the open string to match the fret pattern, you are not moving the frets. SO any saddle adjustment by its very nature will detune the open string. As soon as you change anything at the bridge, your reference no longer applies.
Just set the tuner to E, tune the open string, then check the intonation at the 12th fret. After any adjustment, a quick check of open string and continue.
Using the open string as the reference forgets that as you adjust the bridge, that changes the open string tuning as well. When you adjust your saddles, you are tuning the open string to match the fret pattern, you are not moving the frets. SO any saddle adjustment by its very nature will detune the open string. As soon as you change anything at the bridge, your reference no longer applies.
Just set the tuner to E, tune the open string, then check the intonation at the 12th fret. After any adjustment, a quick check of open string and continue.
I have seen guitars with a bone saddle, where each string has a different support point on the saddle, so that they are not in line. It is achived by filing the front or rear part of the saddle at each string, so that the support point gets closer or farther from the frets.
How it works? For example the rear side is filed so that the support point gets a wedge shape. The total length of the string will be n percent shorter l x (1-n). But if you press the string at the 12th fret, the vibrating half length will not be 1/2 x l x (1-n), but 1/2 x l - l x n, which gives more detuning at half length than at the original length. Called compensated saddle:
Guitar Saddles | Removal, Adjustment, Replacement | Compensated Saddles for Martin, Gibson, Taylor & others
How it works? For example the rear side is filed so that the support point gets a wedge shape. The total length of the string will be n percent shorter l x (1-n). But if you press the string at the 12th fret, the vibrating half length will not be 1/2 x l x (1-n), but 1/2 x l - l x n, which gives more detuning at half length than at the original length. Called compensated saddle:
Guitar Saddles | Removal, Adjustment, Replacement | Compensated Saddles for Martin, Gibson, Taylor & others
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Yes, but each string is supported at each end. At the nut and at the bridge saddle. ANY change you make at either place changes the length of the string and so detunes it. And that means the original string as a reference is no longer valid.
Since I first wrote this, in March 2021 I got myself a guitar. Adjusted the intonation by setting a function generator to the exact open string frequency and feeding it to a scope and syncing the scope to that channel. Feed the guitar signal to the second scope channel and adjust the open string pitch by noting when the second trace creeps neither left or right. Then press on 12th fret and see if the double frequency trace creeps left or right. Adjust bridge a little, reset open string pitch and try 12th fret again. Works great!
https://cdn.shopify.com/s/files/1/0...285c9ff5416582356b0656_2048x.png?v=1615572115
https://cdn.shopify.com/s/files/1/0...285c9ff5416582356b0656_2048x.png?v=1615572115
If you use a tuner with a faux or real needle readout or a pitch frequency you can match the position of the needle or the number until you get close to done with the string, then do it at the correct pitch. It will never be perfect because that needs an intonation adjustment at the nut as well as at the bridge..
You don' need to re-tune the string each time after moving it's bridge support. Using your ears, just do it as described in #3 and use the 1st harmonic as the reference. Intonation ist right if the 12th bar tone is the same as the 1st harmonic.
Best regards!
Best regards!
To set intonation precisely, I always seem to end up checking perfect intervals and octaves on nearby strings at or above the 12th fret. If any beat notes then some more fine tweaking of intonation can usually fix it. The other things is to only set intonation with new strings, as old strings tend to stretch nonuniformly (making intonation nonuniform along the neck).