Precisely intonating an unlined 4003FL: My experience.

[cassius987]

Hi all. I had put my 4003FL away for a while in favor of my 4003S, but got it back out today for a upright-y song needed at church.

(FYI, it was this: https://www.youtube.com/watch?v=VgYRUwN5WWk)

The 4003FL sounded so great (TI JF344 strings, running a 4002 bridge pickup sold to me by good friend Scott Pope), I decided I'm bringing it back as my "main" for a while. So I had a characteristic spell of OCD and decided to precisely check the intonation. (Of course, the final 20-30% of the intonation is really coming from your ears, not your eyes... So my aim here was just to get things precise and consistent across the strings, not achieve the impossible.)

I measured the 12th "fret" inlays centered at 16'' from the nut, and they were 1/4'' in diameter. So 5/8'' closer to the bridge from a center point of either inlay = the "12th fret" position. This turned out to be dead center with the side dot marker that was closer to the bridge, of the two. To help me out while intonating, I put some masking tape down across the fingerboard just behind this marker. (I know... like I said, OCD.)

Before I intonated, my string scales were as follows (to the best of my ability to measure): G - 33.25'', D - 33.31'', A - 33.38'', E - 33.44''. When I was finished, the only string I changed was E, which moved to 33.41''. So it turns out I didn't need to change much at all. However, I thought I'd share my experience in case it could help someone.

For reference, the setup is 3/32'' action for the E string, 1/16'' for the G string, and 1/64'' clearance when measuring the relief off of the 9th position using the string-as-straightedge method.

[jps]

When I had my 4003FL I set intonation by matching up strings at the 12th 'fret" position when stopped with their harmonics in the same position. What i found was the saddles (springs removed) had to be set all the way back (flat) but the strings were still fairly sharp relative to their harmonics. I did my usual mod to the posts of the saddles to gain a bit more travel in their range but that did not help enough; that is why I got the Hipshot bridge that I had put on that bass. That bridge offered a greater range of backwards (flat) movement to the saddles which got the intonation where I wanted it to be. Of course, given how we each hear, and play, fretless instruments, you may find the adjustment range just fine on the stock bridge. Mine was fairly close but I seemed to be getting cursed ,more and more, with pitch sensitivity as I get older!

[cassius987]

Interesting experience, Jeff. Based on my scale measurements, I think the stock bridge would have worked, but I also am using a Hipshot bridge.

Like you, I think my pitch sensitivity has gone up with age (even as I have undergone some hearing loss) -- I chalked it up to increased experience, but who knows.

[jps]

In my case, all the saddles ended up fully towards the rear of the saddle range and I still could not get any string intonated correctly. The tailpiece on that bass must have been mounted a bit forward on the body as there was no more rearward adjustment left to allow getting the intonation any further flat, where as the Hipshot allowed for more rearward adjustability.

[iiipopes]

Glad to see you are playing the 4003FL again.

[cassius987]

Glad to see you are playing the 4003FL again.

Hey Scott! Me too! The 4001FL with three Toasters as well. It's an interesting creature though, the setup is basically "locked" in a dead flat configuration, so higher tension strings are a must. TIs just buzz out on it. Makes for a nice contrast, having LaBella DTFs on that bass.

[Isaac]

In my case, all the saddles ended up fully towards the rear of the saddle range and I still could not get any string intonated correctly. The tailpiece on that bass must have been mounted a bit forward on the body as there was no more rearward adjustment left to allow getting the intonation any further flat, where as the Hipshot allowed for more rearward adjustability.

Back when I was playing guitar, I noticed that heavier strings required moving the saddles back. So maybe lighter strings would give you a little more range of motion.

[jps]

In my case, all the saddles ended up fully towards the rear of the saddle range and I still could not get any string intonated correctly. The tailpiece on that bass must have been mounted a bit forward on the body as there was no more rearward adjustment left to allow getting the intonation any further flat, where as the Hipshot allowed for more rearward adjustability.

Back when I was playing guitar, I noticed that heavier strings required moving the saddles back. So maybe lighter strings would give you a little more range of motion.

I was using the lightest, lowest tension set of Chromes. I even replaced the .060 D string with a .055 string to balance, and lower, the tension even more. That set felt just a bit tighter than TI Jazz Flats.

[Isaac]

It was just a thought.

[jps]

I am pretty certain the tailpiece just needed to be moved back about 1/4", or so, but I did not want to drill new holes.

[lumgimfong]

I am guessing that for fretless one must measure from the inside of the nut, up the fingerboard to the measurement point that equals 1/2 whatever the scale length is to find the correct spot to play the reference harmonic on the string. Is this correct?

[jps]

I am guessing that for fretless one must measure from the inside of the nut, up the fingerboard to the measurement point that equals 1/2 whatever the scale length is to find the correct spot to play the reference harmonic on the string. Is this correct?

I don't make any measurements with tools, I just use my ears, my fingers and an electronic tuner. Different strings require different real world saddle placement so measuring the nominal scale length of the neck is only a rough, at best, starting point. Also, with fretless in particular, finger placement, finger dimensions, and finger "pliability factor" (technical term), makes for a big difference in one's personal intonation settings.

As to finding the 12th "fret" position harmonic, that is pretty easy and does not require precise measuring tools, either. We all know where to place our fingers to find it jut from the references already provided on the fingerboard or side of the neck.