setting the intonation on a fretless

[Woodfield_Bass]

[/indent]Alright, I just installed a new bridge on my fender jazz fretless. I set the saddle length the same all across the board so I could more accurately set the string height and curvature using stewmacs under string radial gauges. Then, I went to set the intonation assuming that it would all be way off. I first tuned all of the open strings perfectly, then went to play the harmonic on the 12th fret thinking this would give a precise reading, but when I played the harmonic on all the strings, it's still in tune! Is this even possible? I'm using a small korg tuner, which has worked great for everything else. Also, when I play, the strings SEEM to be in tune all the way up the neck, or at least not too badly off above the 12th fret. Do I need to use a different technique to check the tuning at the 12th fret? This is puzzling to me...

[Rockman]

The harmonic damn well better be in tune with the open pitch. If not you are doing some serious violations of physics. The technique you use to adjust intonation on a fretless bass is called adjusting your positioning while playing.

[Radio]

Yes, it does make sense, and it's why a pedal steel guitar is intonated properly with the roller nut and "bridge" straight across. Now that's not to say that someone might want to tune the psg to a just tuning, but the harmonics should be good to go. Do you have fret markers on your bass? Their placement could throw you off, since on a fretless, you can tune the notes as you play.

[mat b]

Originally Posted by Rockman

The harmonic damn well better be in tune with the open pitch. If not you are doing some serious violations of physics. The technique you use to adjust intonation on a fretless bass is called adjusting your positioning while playing.

The 12th fret harmonic is half of your string length, producing a harmonic one octave above your open string, these will always be in tune, but a stringed instrument is not a fixed pitch instrument and as you play different harmonics along the string they will become flat, it's called just intonation, Its a (natural) harmonic.

But if your fretless has lines then drop your action to what you like, and then intonate each string by placing a credit card on that string exactly on the line of the 12th fret and then adjust your saddles accordingly. You will always have to shift your fingers slightly while playing but in order to develop better muscle memory you definately want the the e, a, d, and g on the 12th frets to be in the same place

[Woodfield_Bass]

alright, so what I'm hearing is to place a straight edge on the 12th fret line, then adjust the intonation? I guess that makes sense.

[JTE]

Comparing the harmonic to the open string is pointless. It does NOT tell you whether the positions are correct or not. It only tells you that your strings are in good shape and vibrating evenly along their entire speaking length. One sets intonation by comparing the open string (and a harmonic IS the open string) to a stopped note. On a fretless you can set it by stopping the string at the 12 "fret" and adjusting the bridge or you can set it by stopping the string where it sounds right. Both are valid. Instruments in the violin family (including the double bass) have the bridge set so it's pretty accurate, but the actual intonation is up to the player.

FRETTED instruments need the intonation set for two reasons. First, there's some deflection of the string that stretches it when you push it down to the fingerboard. This is inherent in most string instruments where the string is shortened by pushing the string down to the fingerboard (that's why a pedal steel is in tune with a straight bridge- you're not deflecting the strings appreciably). Second, the fret doesn't allow you to make small corrections to the pitch to account for the different deflections caused by different string sizes.

John

[Woodfield_Bass]

ah, i see, thanks for the explanation!