I recently put a fretless neck on my homemade P bass copy...my question is, should the neck be straight as an arrow from nut to bridge, or should there be a bit of a bend up near the nut? Also, when filing the string grooves in the nut, how much space should there be between the bottom of the string and the fingerboard? I currently have about 1/8", and I suspect that I should file the grooves down a bit more, because it's tough after a night of playing to do those E flats, B flats and Fs....I'm just afraid of "going too far" and winding up with buzzes where I don't want 'em (on the open strings).

The amount of relief will depend on the type of strings and the nature of the fretless sound you want. If you are aiming for that 'singing' tone, with lots of fingerboard interaction, then you will want the board to be nearly or completely flat.

Getting to just the right sound is a matter of interplay between neck relief, strings, and bridge height. I'd recommending taking your time and letting the truss rod adjustments settle in after each minor change.

I would approach it by slowly moving the neck to nearly flat, with just a touch of relief, again, waiting until it has truly settled. And I think I'd pick just one string to work with, say, the D or A.

For the time being, forget about the nut.

Bring the bridge adjustment down, bit by bit, until you get the type of sound desired, say at the fifth position, and confirm that you don't have a problem with buzz by playing an Eb or Bb. If you do get undesired fingerboard interaction, you may need to either raise the bridge or add a tiny tweak (and I mean tiny) of relief, or both. After making that adjustment, see how it affected the sound at the fifth and higher positions. And etc., etc., etc. -- patience is key.

If you get good tone at the upper positions but none at the lower, adjust for less relief (less bend); if you get good sound at the 5th position and above, but too much buzz at the first position, add a tweak of relief (more bend).

As you get closer to the right point, you should begin to change the bridge height of the other strings, to see how they all sound, and adjust to taste, as well as see the effect they might have on the neck.

Also, IME, the E can be a challenge at the lower positions and the sound may not be achievable at the lower end of the neck while getting the desired sound on the other strings. But you probably won't be "singing" down there anyway.

If you get to a happy place, let it sit there for a day, and go back for any further adjustments. Then intonate the bass by adjusting string lengths at the bridge.

As far as the nut, 1/8" is high; you can file to go lower, but again, string type and their tautness will determine how low you can go. I wouldn't go so low to cause you to start to worry about fingerboard interaction-- you shouldn't be playing open strings much or at all on a fretless, anyway, because it will sound different from all the stopped notes.

Good luck in your quest.

String bass luthiers generally say the string clearance above the fingerboard at the nut should be the thickness of a business card. I just checked my Carvin 6 and a 3x5 file card will slip under but a Fender Medium pick will not. How's that for a scientific measurement?

As far as relief, I've heard no less than Michael Tobias himself (I think, when he actually owned Tobias) say they used to get their fretless necks dead straight. I have a pretty low action for maximum "mwah", so I've set my neck with a slight relief because I do tend to play hard and a straight board would rattle quite a bit at the lower positions.

I would be relieved if this thread was over in setup where it belongs.:)

Originally posted by reedo35
I would be relieved if this thread was over in setup where it belongs.:)

Now this is the kind of humor...that gives TalkBass a bad name....:D

reedo35,

Thanks for the reminder.

I usually wait a while before moving a thread to a different forum due to the fact that the thread can no longer be preserved simultaneously in the forum from which it started originally.

My girlfriend saw me reading this topic and I said that it was something that I was very interested in and useful to know about, so she asked me to explain it. I said something like, "it's about adjusting your truss rod to get different types of relief" and she gave me a knowing smile and said - are you sure this is about bass? ;)

Got caught timewasting at TalkBasstard again!

For me, it's a compromise between my left hand and my right hand - my left hand wants low relief/action, my right hand wants high. After over a year of experimentation, I've settled on .015" relief at the 7th fret and an action of 1/8" over the 24th fret. Carvin sets the action at 3/32", and although my left hand loves it, my right hand style is just too aggressive and I get too much fret buzz with the action that low. So, I raised the action 1/32", and even that small amount of change made a world of difference. I raised the pickups 1/32" as well, so I'd keep the same approximate tone (and reintonated, of course). I wish I could play with a lighter touch, but it just isn't me. Oh well.

LUMP, ol' buddy!

Welcome back from the other heavy-handed Carvin fan.

Bruce --

sounds like you might be in for some multi-finger technique despite a slack G string. Play light but play long...and maybe you'll get a request for overtime.

WHAT was this thread originally about...?

[Edited by Eli on 09-05-2000 at 07:49 PM]

[QUOTE]Originally posted by lump
After over a year of experimentation, I've settled on .015" relief at the 7th fret and an action of 1/8" over the 24th fret. Carvin sets the action at 3/32", and although my left hand loves it, my right hand style is just too aggressive and I get too much fret buzz with the action that low. So, I raised the action 1/32", and even that small amount of change made a world of difference. I raised the pickups 1/32" as well, so I'd keep the same approximate tone (and reintonated, of course). [/QUOTE

lump,

Like you, I've experimented with the setup on my Carvin (1999 LB70 4-string) for over a year. It was shipped with rather high action; coupled with the bass's light weight, it felt like a cheap instrument.

I set out to get the action ridiculously low, but this eventually got...ridiculous. I'm still experimenting, using Carvin's tolerances as a starting point.

Some observations I've made along the way:

1 Tiny adjustments DO make a difference
2 Some of my height measurements were off because I didn't look "really close".
3 Relief measured with the bass lying flat is not the same as in playing position. Using a 24" straightedge doesn't give you the exact same reading as holding down a string at first and last frets. Carvin's "two stacked business cards" is considerably thicker than .015".
4 An unplugged setup can sound a lot different through an amp - this is what tweaking is all about.

I know that the total setup is affected by lots of factors (even-ness of frets, guage of strings, playing style, etc). Still, I'd be interested in hearing the accurate measurements of any Carvin owners (others too).

Thanks,

Bob

All the posts so far have opted for a flat neck, but there is another option. If you want to have a nice clean sound down low on the neck for grooving, and a nice "mwah" up high for solos and fills, then have some relief (not you Bruce!)similar to the average fretted neck. As stated above, the best way to measure this is by holding down the first and seventeenth "frets", and eyeballing the gap at the ninth "fret". This should be around .014" or, I think, a Fender medium pick. Some fretless players find this is a more useable setup, because the damn bass is'nt growling at you all the time!

But it's SUPPOSED to growl at you all the time!