Why the difference in nuts?

[Flamingo21]

not to sidetrack the thread, but now I wonder if violinists or other similar instrumentalists have the same discussions over round wounds vs flats etc??? Or do they all use the same type strings just different lengths?

I was a viola player for many years, and there was a lot of talk about string types and brands. Those discussions were never heated, and never philosophical. Nothing like what we're used to over here.

I think the explanation for this is the fact that classical instruments (except very cheap ones) are individual builds, they aren't built in series like most bass guitars. So every instrument is an individual, which is immediately apparent to anyone playing it, therefore individual string choices are a logical thing.

 

[alexclaber]

I wish more builders would use a zero fret or wood nut for fretless. It makes the open strings match the tone of the rest of the instrument better. Also a plus when you change string gauges or use a bead tuning for instance.

In my experience a zero fret makes open strings sound less like fretted strings than a more typical bone or synthetic bone nut. My hypothesis for this is that your finger adds significant damping when fretting the note and with a zero fret you don't have that damping. I had a custom bass made about 15 years ago which has an ebony nut and the open strings on that sound more like the fretted notes than on any other bass I've played, possibly because the ebony's relative softness gives a similar level of damping as a finger pressing down behind a fret.

 

[coy garcia]

In my experience a zero fret makes open strings sound less like fretted strings than a more typical bone or synthetic bone nut. My hypothesis for this is that your finger adds significant damping when fretting the note and with a zero fret you don't have that damping. I had a custom bass made about 15 years ago which has an ebony nut and the open strings on that sound more like the fretted notes than on any other bass I've played, possibly because the ebony's relative softness gives a similar level of damping as a finger pressing down behind a fret.

I respectfully disagree. I almost always play fretless and i really appreciate a ebony zero fret for tone balance to open strings. If my fretted basses had one it would be easier to change string gauges. I'm sure it's just a player preference thing.

 

[alexclaber]

I respectfully disagree. I almost always play fretless and i really appreciate a ebony zero fret for tone balance to open strings. If my fretted basses had one it would be easier to change string gauges. I'm sure it's just a player preference thing.

When you say an ebony zero fret, do you mean that the "fret" is made of ebony?

 

[RichterScale]

Yep, I think everyone is referring to different things and getting crossed up.
I'm building a fretted bass.
It will have a zero fret.
The strings will sit in a wood nut behind the zero fret to hold them in place.
I didn't do that for any tonal reason. Just as a cool design feature as it will be part of the FB. Plus, I don't have to fuss over nut slots being perfect. The speaking length ends at the zero fret and the slots in the nut just have to be the right width and hold the strings in place.
It's a good point about there being some damping by fingers on fretted notes. I hadn't considered that. So, my setup may actually turn out to sound pretty good, in terms of consistent sound, based on a zero fret and wood nut behind it.
Although, it wasn't planned and I wasn't concerned.
I've always noticed a difference in the sound of open strings on every bass I've ever played. I never gave it much thought other than I would use it to my advantage when I thought the open note sounded better than the same note fretted. But for the most part, the difference in the sound didn't influence my playing or now, my building.

 

[fhm555]

Acoustic guitars have a thin nut

When I was a wee lad my dad had an old flattop guitar with a wide nut rounded on the peg side. Strange what you remember from early childhood. I think it may have been because of the difference between the nut on his acoustic and the one on his Silvertone arch top electric. He played the electric more so I saw it more and while I recall much more about it I just remember the flattop was really beat up and had a strange looking piece at the end of the neck compared to his electric.

 

[coy garcia]

When you say an ebony zero fret, do you mean that the "fret" is made of ebony?

Yes like a violin. Here is my main player 1st and the one that is being built. Both by my favorite luthier @Bruce Johnson who commented on this post. They both have the zero fret made from the fretboard wood.

 

[mrperkolator]

I'm here for the pictures.

 

[vvvmmm]

Ball-ends use zero-fret nuts, of course.

 

[-Asdfgh-]

No, I wouldn't say it's more important on acoustic instruments. On both acoustic and electric instruments, it's about the transmission of vibration from the string into the neck and frame. That vibration then gets reflected back from the frame into the string, which may modify the sound on the string.

On an acoustic, that modified string vibration then pumps the bridge up and down, which pumps the top, and pumps out acoustic sound. The flexing of the frame by the string can affect the final acoustic sound.

On an electric bass, that modified vibration on the string is read by the pickup, tweaked a bit by the pickup's own internals, and sent on down the wire to the amp.

In both cases, this interaction on the frame is changing the "sound" on the string before it goes off and becomes real acoustic sound.

That secondary vibration is unlikely to be in phase with the string's vibration, I would have thought, and the phase differences would cause slight comb filtering, wouldn't they?

 

[-Asdfgh-]

Yep. It's all about how much of angle you need to bend the string through. You don't want to kink the string to too small of a radius.

But, adding more solid contact between the string and nut and neck will also help with high frequency clarity.

Here's one of my Scroll Basses, with a very high break angle, a zero fret, and a wide aluminum nut with curved radiused slots. Real good contact area, smooth tuning, and minimal kinking of the flatwounds.

View attachment 4565516

On a flat or lightly tilted headstock, with less than 10 degrees of break angle, a wide nut isn't necessary. So the manufacturers use narrow nuts, because they are cheaper.

That looks beautiful.

 

[Discount Bassy]

I am no luthier, but it seems to me that the crucial point of contact in the acoustic string family is the bridge and sound post, more so than the nut.

 

[TFM94]

It is somewhat paradox to find praise for both extra wide nuts and zero frets in the same thread, as they are generally opposite. A zero fret is technically the thinnest possible nut.

I know that most zero fret instruments have a nut guiding the strings behind the zero fret. As @Bruce Johnson pointed out, the benefit of a wide nut is the high break angle and secure guiding fo the string through the nut with strong downforce. Again a zero fret is the exact opposite, typically the break angel right over the fret is shallow and the string has a bit of give to either side to slide over the fret, at least if there is some distance between the zero fret and the nut behind it.

 

[Bruce Johnson]

However......everywhere else (the nut on all stringed instruments, and the bridge on a solid body), you want to transfer very little (ideally, none) of the strings' energy into the neck or body. Sustain (we obviously want a fair amount of that, or we wouldn't ever buy solid bodied instruments) comes from NOT transferring vibration into the instrument's body and neck - the nut, fret or bridge should present a solid platform that does not move (or does very little movement) so the energy stays in the string.

Yeah, I need to clarify that (so to speak). When you use a well-seated metal nut, it's making the contact between the string and the wood frame more rigid, less squishy. That reduces the energy drawn out of the string, leaving the sound and sustain as they were. Up in the high frequency range. The highs are clearer because the string isn't able to transfer vibration in that frequency range through the rigid nut. A softer, more squishy nut will make the high end softer, less clear, shorter sustain.

But meanwhile, the mid and low frequency vibration is still being transferred to the wood frame, through the nut (and the other anchor points). If the frame is soft and flexible enough, it will flex and vibrate, at those lower range frequencies. This is what fights back against the string, drawing down its energy and modifying the sound on the string. It adds background harmonics and a shaped attack profile. Character to the sound on the string.

If you build the entire frame really rigid, then you will transfer very little of the string's energy into the frame. And the sound on the steel string sounds like...a steel string. Bright, metallic, piercing, long sustain. Maybe that's what you want? But we Luthiers mess around with softening the wood frame specifically to modify that sound, to make it sound less like a steel string. To add character that can't be added by pickups and electronic circuits.

But we do different things to modify different parts of the frequency range. Nuts, bridges and tailpieces are made rigid to improve high end clarity. Bodies are made soft and flexible to increase mid-range background harmonics and coloration. Necks are made rigid along their back spine, but compressible along the front. Neck/body joints are made more rigid.

There are lots of structural things we do to play around with the sound of an electric bass. And they are all going on at the same time. They do different things.

 

[Bruce Johnson]

That secondary vibration is unlikely to be in phase with the string's vibration, I would have thought, and the phase differences would cause slight comb filtering, wouldn't they?

Yes, that's exactly it. If the vibration of the frame exactly matched the vibration of the string, it would just cancel out and kill it. But the frame's counter-vibration is slower, gets out of phase, and is more powerful in some frequency ranges than others. So the canceling is partial and uneven.

 

[micguy]

But meanwhile, the mid and low frequency vibration is still being transferred to the wood frame, through the nut (and the other anchor points). If the frame is soft and flexible enough, it will flex and vibrate, at those lower range frequencies. This is what fights back against the string, drawing down its energy and modifying the sound on the string. It adds background harmonics and a shaped attack profile. Character to the sound on the string.

If you build the entire frame really rigid, then you will transfer very little of the string's energy into the frame. And the sound on the steel string sounds like...a steel string. Bright, metallic, piercing, long sustain. Maybe that's what you want? But we Luthiers mess around with softening the wood frame specifically to modify that sound, to make it sound less like a steel string. To add character that can't be added by pickups and electronic circuits.

But we do different things to modify different parts of the frequency range. Nuts, bridges and tailpieces are made rigid to improve high end clarity. Bodies are made soft and flexible to increase mid-range background harmonics and coloration. Necks are made rigid along their back spine, but compressible along the front. Neck/body joints are made more rigid.

There are lots of structural things we do to play around with the sound of an electric bass. And they are all going on at the same time. They do different things.

I hope your realize the nut is not really in the picture that much if you're playing a fretted note - open strings are where it makes (by far) the most difference.

Stiffness and mass are 2 of the 3 things you have in the impedance that the string sees at its ends - damping is the 3rd - which is important, but is also a mixed bag. Too much damping, and the whole instrument sounds lifeless (especially on an acoustic). Too little damping in the neck, and dead spots are much more likely to show up and be bothersome. The other thing about damping is it changes over time - as the lignin in the wood crystallizes, you get less damping, and the character and dead spots change. One really good reason for roasted wood (particularly in the neck of a solid bodied instrument) is that you essentially move ahead in time - you get to hear what the instrument will sound like in 20 years, because the wood is already "aged".

 

[Lowbrow]

 

[Bruce Johnson]

I hope your realize the nut is not really in the picture that much if you're playing a fretted note - open strings are where it makes (by far) the most difference.

That's not really true. When you press down a string at a fret, nothing really changes at the nut. The string back there still has the same tension, the break angle is the same, and the download on the nut is the same. The vibration is still transferred from the string down through the nut, as it was when it was played open. The only thing different is the vibration frequency of the string, because you've stopped its length at the fret. A little bit of vibration goes down through the fret into the fingerboard, but it's not much, because there isn't much download on the fret. Your finger pressure behind the fret is far less than the normal download on the nut.

 

[micguy]

That's not really true. When you press down a string at a fret, nothing really changes at the nut. The string back there still has the same tension, the break angle is the same, and the download on the nut is the same. The vibration is still transferred from the string down through the nut, as it was when it was played open. The only thing different is the vibration frequency of the string, because you've stopped its length at the fret. A little bit of vibration goes down through the fret into the fingerboard, but it's not much, because there isn't much download on the fret. Your finger pressure behind the fret is far less than the normal download on the nut.

When you fret a note, the frequency at which it vibrates changes, because only the part of the string between the fret and the bridge is vibrating. The string is not vibrating at the nut anymore - the place where any vibration enters the neck has changed. Yes, the static pressure on the nut hasn't changed much, but that has nothing to do with the acoustics/vibration of the situation.

If you fret your G string at, say the 6th fret, and it's a dead spot, it's a dead spot because there's an antinode there (at that one point on the neck) at that frequency - the vibration is definitely entering the neck system (too easily) at that point. If the energy always enters the neck at the nut, the neck would be dead for that frequency everywhere. But isn't - try the 11th fret on the D string (or the 16th on the A) - it won't be dead. It's a dead spot, not a dead frequency. Vibration is coupled to the neck at the fret, not the nut.

 

[Bruce Johnson]

When you fret a note, the frequency at which it vibrates changes, because only the part of the string between the fret and the bridge is vibrating. The string is not vibrating at the nut anymore - the place where any vibration enters the neck has changed. Yes, the static pressure on the nut hasn't changed much, but that has nothing to do with the acoustics/vibration of the situation.

You are misunderstanding how the vibration is being transferred to the frame. When the string is singing away, the center portion of it between the two fulcrum points is swinging back and forth in free air. It's not hitting anything (hopefully). The vibration is transferred to the frame by the two ends of the string pulling and releasing on the two anchor points. Cyclic pulses pulling the tuner post and the tailpiece toward each other. The majority of that pulsing load gets transferred to the frame through the tuner post and the tailpiece. But a portion of that pulsing goes down through the bridge saddle and the nut, because of the string being bent over them. The larger the break angle, in either place, the more of the pulsing is directed down vertically. Vectors of forces.

Not much of the vibration is transferred down through an intermediate fret, because there's hardly any break angle over it. The pulsing load at that point is all happening horizontally.