Cha, cha, changes, my intonation changes

[Bingo Player]

Thanks to Doctor Bass for this sample image of the Hofner bass.

Please, note the bass has a fret just after the nut. Then the normal "1st" fret. Is this very unusual or are there other brands that use that "0th" fret?

I've been trying for several days to get intonation for my Hofner Club bass with the floating bridge. So if I measure the distance (as I've read in other posts) do I start at the nut or the 0th fret?

I've noticed a few things I've never looked at before, like, the low F is way sharp. I mean if the open E and the octave and the harmonic at 12 are really close, I'd expect the F to be pretty close to, but it isn't.
My tuner's scale is -50 ...0...+50 and the F is reading around +20 or +25.

To many odd things and questions, but here is the one for this moment: while setting the open E and picking lightly versus hard, the intonation gets more sharp, same at the octave, but not as much.

Oh, an this one too: when I play the low F and press my finger down harder or not so hard, then intonation changes!

[ehque]

Originally Posted by Bingo Player

Thanks to Doctor Bass for this sample image of the Hofner bass.

Please, note the bass has a fret just after the nut. Then the normal "1st" fret. Is this very unusual or are there other brands that use that "0th" fret?

I've been trying for several days to get intonation for my Hofner Club bass with the floating bridge. So if I measure the distance (as I've read in other posts) do I start at the nut or the 0th fret?

I've noticed a few things I've never looked at before, like, the low F is way sharp. I mean if the open E and the octave and the harmonic at 12 are really close, I'd expect the F to be pretty close to, but it isn't.
My tuner's scale is -50 ...0...+50 and the F is reading around +20 or +25.

To many odd things and questions, but here is the one for this moment: while setting the open E and picking lightly versus hard, the intonation gets more sharp, same at the octave, but not as much.

Oh, an this one too: when I play the low F and press my finger down harder or not so hard, then intonation changes!

Zero frets are quite common, searching for "zero fret" should turn up quite a few threads.

To address the sharp F, is it the same for all the first fret notes on all strings? If it is your zero fret is too high, or your 13th fret is mispositioned. What tuner are you using? Many are not accurate enough to do intonation work on.

[joebar]

the way to set intonation is to have an electronic tuner. when your bass is intonated properly, for example, a harmonic on your A string (fifth fret ) should be the same as when you press down the octave on the 12 fret. when the tuner shows that your open string and a higher fretted note hit the same calibration, then the other notes will be very close.
if for examplem the open string registers in tune but the fretted octave is sharp (on the tuner's reading) then an adjustment would have to be made on the bridge saddle ( the saddle would need to be moved backwards to flatten the fretted note.) if the octave was flat, the saddle would have to be moved forwards. that is it in a nutshell.
if after many attempts and the guitar is getting strange readings allover the fretboard, then there might be a more serious problem; even the cheapest of guitars usually can be intonated accurately. since intonation is a measurement, it is basically distance. there is not much that can go wrong. the bridge saddle can be manipulated fore or back to reach the proper distance of a fretted note.
incidentally, once the saddles are set, they don't need to be adjusted again; the only time they need to be is if you change string gauge. if they never move then you should be good to go for some time.
i am not an expert- just a guy who figured out to do what the luthier would charge me for

[joebar]

also- if you were to raise or lower the action, this would require you to adjust the intonation as well. anytime you change the distance, reintonantion is needed.

[rumblethump]

With a compensated bridge like yours, I usually intonate the G and E strings and live with whatever the A and D strings end up.

[JTE]

The zero-fret is pretty common on many European instruments. It was looked down on in the US because other than Gretsch, no major US maker during the boom of the guitar (that is, neither Gibson, Fender, nor Martin) used a zero-fret so most people only saw them on cheap imports. Therefore the idea of the zero fret got associated with cheapness. However it does have some advantages.

The correct way to set your intonation is to have the bass in playing position because the weight of the headstock and the pressure you put on the neck can cause some necks to move enough to make a difference. Make sure your strings are in good shape because the whole idea of intonation for a fretted instrument is predicated on the assumption that the string is vibrating evenly along its length. Then play the open string (or any of the octave harmonics- that's the 12th fret and the 5th fret). The physics of a vibrating string make it so that the octave harmonics ARE exact octaves unless your string is bad.

Then fret the string at the 12th fret- you're comparing the fretted octave to the open string or its partials. If the fretted note is flat, that means the string is too long between the 12th fret and the bridge. So, you have to move the saddle closer to the nut. If the fretted note is sharp, the string is too short between the 12th fret and the saddle, so you move the saddle away from the nut.

The problems come in with two areas. First, is the string breaking over the saddle? It needs to have a good witness point at the saddle, and bigger strings are more likely to curve instead of bend there. Put some pressure down on the string right in front of the saddle and try again. The second problem is the accuracy of what you're using to compare the fretted note and the open string. Most peoples' ears get tired really fast and loose the ability to make very fine pitch discrimination after a short while. And many tuners while accurate enough to get in tune to play with other people, aren't accurate enough to do a good job of setting intonation. That's because a very slight variance in setting intonation gets amplified.

If my tuner is accurate to +/- 5 cents, then my open string could be as much as 10 cents away from the fretted note, yet still read as being the same pitch. If my tuner is accurate to +/- 0.5 cents, then the swing can only be off by 1 cent.

If after doing a careful and painstaking intonation adjustment and the fretted notes are still off enough to cause problems playing with others (there in no way a fretted instrument every is exactly in tune up and down the entire two octaves) then look at the zero fret being worn and not the right height. That bass looks like the saddles are not fully adjustable, but have slots maybe? That could be the problem too- you just can't get the saddle exactly where it needs to be.

John

[Bingo Player]

Thanks to all. I've spent an hour or so a day for the last 3 days tweaking, resetting, tweaking...and realizing I might need to adjust the neck to get better results, but I've never done that and it scares me to think I could get things even worse.

So, what tips, clues or outright warnings do you have about MY doing this?