Intonation advice

[CamdenRob]

Some more advice needed from you good people...

I've recently replaced the bridge saddles on one of my basses and I need to adjust the intonation slightly on a couple of strings but I'm not entirely sure what I'm doing... The note at the 12th is sharp from the harmonic so which way do I need to move the saddle to compensate? closer to the bridge (making the string longer) or further away from the bridge (making the string shorter).

Thanks guys.

[KiOgon]

Sharp is short & flat is long if the harmonic is sharp the string is too short - you need to move the saddle further away from the nut.

HTH

John

[CamdenRob]

[quote name='KiOgon' timestamp='1386749105' post='2303881']
Sharp is short & flat is long if the harmonic is sharp the string is too short - you need to move the saddle further away from the nut.

HTH

John
[/quote]

and there it is... basschat comes up with the goods again.

Thank you John, much appreciated.

[gary mac]

Sometimes Rob, it is necessary, whilst turning the screw, to also give the saddle a gentle nudge in the direction you want it to travel.

[CamdenRob]

[quote name='gary mac' timestamp='1386750448' post='2303901']
Sometimes Rob, it is necessary, whilst turning the screw, to also give the saddle a gentle nudge in the direction you want it to travel.
[/quote]

I'll give it a whirl tonight Thinking about it, I guess its pretty obvious that by moving the saddle back towards the bridge the distance between a fretted 12th fret and the saddle is longer so this will make the note lower...

[PlungerModerno]

I remember it as "Flat goes Forward" i.e. if the fretted 12th is flat when the open note is in tune, then the saddle should be moved forwards towards the nut, shortening the string. The definition of backwards is "back towards the bridge" - defining forwards as towards the nut.

That's how I remember it anyway. Try gently adjusting the G string each way and it'll be very apparent. The thicker strings tend to need a little help getting the kink over the saddle so I would recommend experimenting with a thinner string which tends to adjust itself.

[Count Bassy]

[quote name='KiOgon' timestamp='1386749105' post='2303881']
Sharp is short & flat is long if the harmonic is sharp the string is too short - you need to move the saddle further away from the nut.

HTH

John
[/quote][quote name='KiOgon' timestamp='1386749105' post='2303881']
Sharp is short & flat is long if the harmonic is sharp the string is too short - you need to move the saddle further away from the nut.

HTH

John
[/quote]

I'm pretty sure it's the other way round I.e. if the [i]fretted [/i]note is sharp then you move the saddle away from the nut.

The whole point is (I thought) that the harmonic at the 12th has to be an exact octave above the open string, irrespective of string length.

[booboo]

Is it best to tune intonation at the bridge to the harmonic or the fretted note at the 12th fret? For those of us more likely to be playing mustang sally than portrait of Tracy surely it's the fretted note?

[Count Bassy]

[quote name='booboo' timestamp='1387161894' post='2308920']
Is it best to tune intonation at the bridge to the harmonic or the fretted note at the 12th fret? For those of us more likely to be playing mustang sally than portrait of Tracy surely it's the fretted note?
[/quote]

The point is that you cannot tune the harmonic. The harmonic (at the 12th fret - at the mid point of the string) is always an exact octave above the open string!. If correctly intonated then fretting at the 12th fret is also an exact octave. If the intonation is wrong then the fretted note is out of tune with the harmonic, but it is always the harmonic which is the reference, to which the fretted note should be tuned using the bridge adjustment.

If the bridge is way out, say a 10mm, then the harmonic then you'd have to touch the string 5mm beyond the 12th fret to get the true harmonic, but it would still be an exact octave above the open string. If you tried touching the sting directly above the 12th fret in those circumstances then you wouldn't get much of a harmonic..
.