Increase string tension by reversing headstock?

[pilotjones]

I wonder if the technology could be adapted to bass. Granted, a piano string only produces one fundamental ever, but I think if the longitudinal frequency were tuned to one of the upper transverse partials when the string is open, when you fret a note, since you're changing only the speaking length of string and not any of the other contributors to the longitudinal mode frequency, wouldn't the longitudinal frequency always change by the same amount as the transverse mode frequency?

Good question. The relation of transverse frequency being (linearly) inversely proportional to the speaking length is part of the "standard transverse" string equation. I don't know the equation for longitudinal vibration, but I expect the frequency is most likely inversely proportional to either the length, the square of the length, or maybe the square root of the length. It would be nice if it were also linear, as you suggest, so the relationship would remain constant with fretted notes. Then there could be some experimenting going on!

 

[thepontif]

Good question. The relation of transverse frequency being (linearly) inversely proportional to the speaking length is part of the "standard transverse" string equation. I don't know the equation for longitudinal vibration, but I expect the frequency is most likely inversely proportional to either the length, the square of the length, or maybe the square root of the length. It would be nice if it were also linear, as you suggest, so the relationship would remain constant with fretted notes. Then there could be some experimenting going on!

Well hopefully Conklin will get back to me and I can ask him. I imagine he'll know all of that first hand.

 

[thepontif]

Good question. The relation of transverse frequency being (linearly) inversely proportional to the speaking length is part of the "standard transverse" string equation. I don't know the equation for longitudinal vibration, but I expect the frequency is most likely inversely proportional to either the length, the square of the length, or maybe the square root of the length. It would be nice if it were also linear, as you suggest, so the relationship would remain constant with fretted notes. Then there could be some experimenting going on!

As I think about it, if the longitudinal mode frequncy of a 34 inch long string is 1kHz (for sake of easy math), then it takes the wave 1ms to get from the bridge to the nut and back again. So if you make the distance 17 inches, the wave will take half the time to make the journey. Hence, the period is 500uS and the frequency should double to 2kHz. The speed of the wave theoretically can't change as long as the material and temperature stay the same. That's how I understand it.

 

[pilotjones]

As I think about it, if the longitudinal mode frequncy of a 34 inch long string is 1kHz (for sake of easy math), then it takes the wave 1ms to get from the bridge to the nut and back again. So if you make the distance 17 inches, the wave will take half the time to make the journey. Hence, the period is 500uS and the frequency should double to 2kHz. The speed of the wave theoretically can't change as long as the material and temperature stay the same. That's how I understand it.

Yeah, that makes sense... still a one-dimensional problem, so still a first-order relationship.

 

[jcoopcoyote]

To Mike Pope and the other Pro's who have chimed in on this thread. I just want to take a minute to thank you. I guess I'm a little star struck.
I'm just a guy that plays in local weekend cover bands and likes to tinker with my short scale basses to get the most out of them. I had spotted that article in BP Magazine and knew it would be an interesting topic of conversation. I had no idea it would draw this kind of attention. This forum is truly awesome to bring all kinds of people together in this way. Thanks again!

 

[thepontif]

I for one enjoy these kinds of talks. It's really interesting when you start digging into it, actually. Belief often takes precedent over knowledge with these kinds of issues and often the facts can seem counterintuitive. When things appear so clearly counterintuitive (usually because you don't have all the facts), it's easy to want to attribute the unknowns to some kind of pie-in-the-sky magic sort of thing. It's kind of like what I mentioned earlier about the Piano Technician's Guild "believing" that octaves in a piano have to be stretched because the string has inharmonicity (I've been spelling that word wrong apparantly). It's totally wrong, both in theory and in practice. It's amazing, though, when both the physics/math AND the result support that it's not the right thing to do, they still tell you it is... purely based on belief from what they've been told. With stretched string instrument design there has been SO much research done over the years. High speed photography and spectral analysis and testing that only a very few people with LOTS of very specialized resources have done. The hard, fast facts are out there. Finding them is difficult because there aren't very many people who give a rats howyadoin' about it. Maybe someday, MIT will offer a class entitled "Superstition as a design criterion" and then I'll shoot myself. Or buy a faith based calculator....

 

[thepontif]

Ok. So here' s new twist. After talking to my partner, David Yates, an engineer with nearly 40 patents in his name, I have another factor we haven't touched on. According to Conklin, the speaking length of the string is the "length" term used to determine the longitudinal mode of vibration IN A PIANO. Now a piano string is hard terminated at the agraff (nut) and the bridge pins. Take a look at it. There is tremendous break angle upward at the pressure bar at the agraff end, and sideways at the bridge. Downbearing is handle independent of break angle in this case because it's such a critical part of piano soundboard vibration. On a bass, if the angle is shallow over the nut or bridge, the portion of the string beyond the breakpoint still carries the compressional longitudinal wave. There's nothing to stop it. It's probably affected by what break angle there is, but it isn't stopped. In particular, the fretting of a note won't stop it. It might interfere somehow, but it wouldn't stop it. I think a really interesting experiment would be to somehow put a piezo transducer in between the ball end of a string and the "tailpiece" it's anchored in. If my hypothesis is correct, the frequency of the electrical signal coming from the piezo should stay pretty much the same regardless of just about anything given the same string. I wonder if there's a way to do that? This scenario wouldn't make the Synchrotone string conept useable on a fretted instrument. And by the way, the big deal with it is that they control the distance between the wraps of the winding in order to tune the Long. mode of vibration. Also maybe not desireable in terms of feel on a bass. Maybe kind of rough feeling...

 

[pilotjones]

Ok. So here' s new twist. After talking to my partner, David Yates, an engineer with nearly 40 patents in his name, I have another factor we haven't touched on. According to Conklin, the speaking length of the string is the "length" term used to determine the longitudinal mode of vibration IN A PIANO. Now a piano string is hard terminated at the agraff (nut) and the bridge pins. Take a look at it. There is tremendous break angle upward at the pressure bar at the agraff end, and sideways at the bridge. Downbearing is handle independent of break angle in this case because it's such a critical part of piano soundboard vibration. On a bass, if the angle is shallow over the nut or bridge, the portion of the string beyond the breakpoint still carries the compressional longitudinal wave. There's nothing to stop it. It's probably affected by what break angle there is, but it isn't stopped. In particular, the fretting of a note won't stop it. It might interfere somehow, but it wouldn't stop it. I think a really interesting experiment would be to somehow put a piezo transducer in between the ball end of a string and the "tailpiece" it's anchored in. If my hypothesis is correct, the frequency of the electrical signal coming from the piezo should stay pretty much the same regardless of just about anything given the same string. I wonder if there's a way to do that? This scenario wouldn't make the Synchrotone string conept useable on a fretted instrument. And by the way, the big deal with it is that they control the distance between the wraps of the winding in order to tune the Long. mode of vibration. Also maybe not desireable in terms of feel on a bass. Maybe kind of rough feeling...

As is necessarily the case, there are a lot of assumptions here. You're assuming the witness breaks on a piano are sufficient to act as nodes for longitudinal vibration; I'd probably assume likewise. On a bass, depending on break angles, this might or might not be true. Or, influenced by factors such as the core never making contact with the nut (and often the bridge), the longitudinal vibration may never be fully stopped at the nut. I'd probably also make the same assumption that fretting would give no more than--maybe a 50% "node quality" (stopping/reflecting the axial vibration). AFA the Syncrotone strings, there's got to be some accounting for the significant bare core at both ends of a piano string, too.

 

[pilotjones]

I for one enjoy these kinds of talks. It's really interesting when you start digging into it, actually. Belief often takes precedent over knowledge with these kinds of issues and often the facts can seem counterintuitive. When things appear so clearly counterintuitive (usually because you don't have all the facts), it's easy to want to attribute the unknowns to some kind of pie-in-the-sky magic sort of thing. It's kind of like what I mentioned earlier about the Piano Technician's Guild "believing" that octaves in a piano have to be stretched because the string has inharmonicity (I've been spelling that word wrong apparantly). It's totally wrong, both in theory and in practice. It's amazing, though, when both the physics/math AND the result support that it's not the right thing to do, they still tell you it is... purely based on belief from what they've been told. With stretched string instrument design there has been SO much research done over the years. High speed photography and spectral analysis and testing that only a very few people with LOTS of very specialized resources have done. The hard, fast facts are out there. Finding them is difficult because there aren't very many people who give a rats howyadoin' about it. Maybe someday, MIT will offer a class entitled "Superstition as a design criterion" and then I'll shoot myself. Or buy a faith based calculator....

Mike, have you got some material on stretch tuning being wrong? Because I think I have a good understanding of it, and I think it makes perfect sense. The first people to do it didn't do it because a theory told them to (and BTW theory on a "real string" as opposed to an "ideal string" does explain why the upper partials go sharp), or because they did a Fourier analysis and found the inharmonicity of the upper partials. They did it because they heard the inharmonicity, and the stretch tuning sounded better than a straight tuning.

 

[Munjibunga]

Stiffness and tension are 2 different parameters. I take care not to merge them, please don't do it.
The same string mounted on 2 different instruments at the same tension can have a completely different stiffness. One may feel loose while the other will feel tight.
The reason is usually a better assembly and a more rigid neck, as I'm sure you know. A much safer and simpler way.
String afterlength can also sometimes affect stiffness but it won't change tension.

More BS. The stiffness is a function of the construction of the string.

 

[Angus]

I put piezo cabling in an old bass a while back (and have 2 instruments coming using it as well), going all the way through the neck (running parallel to the truss; not attached to it). It works similar to transducers, though the way I have it set up I can get the signal from specific lengths of it or the entire bit. Sounds great.

It also has a piece running under the nut. Doesn't sound great, but does have some interesting effects.

What doesn't happen, though, is what you mentioned Mike. If I take just the section under the nut, you hear a combination of the vibration in the neck (the sounded pitch) and some inharmonic tones that are generated by the string length between the nut and tuner. If you turn off the section at the nut and turn on sections between the nut but before the fretted note, you get another set of inharmonic overtones that do change as the the fretted note changes. You still faintly hear the same set that occur a past the nut because of the sensitivity of the piezo cable I'm using.

It's an old P bass, so it has a very, very shallow break angle because of the straight peghead. This would imply that there is a significant enough amount of vibration present in the portion past the nut that you can't treat the speaking length quite the same as on a piano (or a headless bass). But I would argue that it still doesn't have enough of an effect on the issue of string tension; break angle over the nut would have more of an effect on the 'feel' of the string because of the different pressure gradient across the contact patch of the string on the nut.

It should be noted that the cabling I'm using to do this is extremely sensitive- a 1 inch piece buried 6 ft under ground can measure the vibrations of a child running around 200+ ft away. It's awesome.

None of this has much to do with the actual discussion though. I've talked to a number of different professors and musicians and piano tuners, and all of them have very different opinions on the Fourier/stretched tuning issue. I get to work with guys like Max Matthews and John Chowning and the like and they all have opinions on which is the 'right thing to do' versus 'what sounds right' so it's not something I'm going to get into!

 

[thepontif]

I put piezo cabling in an old bass a while back (and have 2 instruments coming using it as well), going all the way through the neck (running parallel to the truss; not attached to it). It works similar to transducers, though the way I have it set up I can get the signal from specific lengths of it or the entire bit. Sounds great.

It also has a piece running under the nut. Doesn't sound great, but does have some interesting effects.

What doesn't happen, though, is what you mentioned Mike. If I take just the section under the nut, you hear a combination of the vibration in the neck (the sounded pitch) and some inharmonic tones that are generated by the string length between the nut and tuner. If you turn off the section at the nut and turn on sections between the nut but before the fretted note, you get another set of inharmonic overtones that do change as the the fretted note changes. You still faintly hear the same set that occur a past the nut because of the sensitivity of the piezo cable I'm using.

It's an old P bass, so it has a very, very shallow break angle because of the straight peghead. This would imply that there is a significant enough amount of vibration present in the portion past the nut that you can't treat the speaking length quite the same as on a piano (or a headless bass). But I would argue that it still doesn't have enough of an effect on the issue of string tension; break angle over the nut would have more of an effect on the 'feel' of the string because of the different pressure gradient across the contact patch of the string on the nut.

It should be noted that the cabling I'm using to do this is extremely sensitive- a 1 inch piece buried 6 ft under ground can measure the vibrations of a child running around 200+ ft away. It's awesome.

None of this has much to do with the actual discussion though. I've talked to a number of different professors and musicians and piano tuners, and all of them have very different opinions on the Fourier/stretched tuning issue. I get to work with guys like Max Matthews and John Chowning and the like and they all have opinions on which is the 'right thing to do' versus 'what sounds right' so it's not something I'm going to get into!

I don't disagree with anything you said. I'm not suggesting puting a transducer under anything. I suggested putting a transducer between the ball and the tailpiece, perpendicular to the string. Up and down vibrations aren't the issue in this case. It's the way the string vibrates end to end. Although the transverse displacements in a string run from end to end, this is not the longitudinal mode.


As for the stretched tuning...have a piano tuned stretched and record it...then tuned beatless octaves and record it. The sustain, warmth, and synergy of the beatless tuning is better. It's night and day. Tuning a string to an out of tune harmonic in a lower string emphasizes the out of tune harmonic. It sounds bad. Play C0 and C3 together and listen to how obnoxious it sounds. By the time that distance is covered, the deviation from the exact multiple is significant and obvious. It's a bad idea, but no member of the PTG will ever agree with me. My tuner (Conklin's former assistant) tunes my piano with no stretch and it sounds gorgeous.

We're way off topic here...sorry to do that.

 

[JonathanD]

When he replaced the neck, he probably just made it have a little higher action. The strings feel stiffer because you have to press harder to fret.

 

[ehque]

When he replaced the neck, he probably just made it have a little higher action. The strings feel stiffer because you have to press harder to fret.

We've moved quite far from THAT discussion already, JohnD.

Tension as a concept is not enough to define a string in my opinion. The physics idea of tension being solely a function of mass/length (density), length and pitch requires that the string be only slightly deviated from the normal. Same as pendulums - they act less and less ideally as the distance from equilibrum increases.

Perhaps tension could be split up into static tension - the tension in a non-vibrating string - and dynamic tension - the force required to pull the string a certain distance off normal. Kind of like resistance and impedance. I'd be willing to bet that even though same strings at same lengths have the same static tension, as dictated by physics, the dynamic tension can vary wildly from bass to bass, due to things like neck rigidity (a flexible neck will flex forward when the string is pulled, reducing dynamic tension).

Secondly, the Longitudinal / Transverse theory is quite interesting. In my head, transverse vibrations are stopped quite effectively by things like the nut and fret, but i believe that the long waves will pass QUITE effectively past the fret or the nut. Vibrato works, you see.

 

[otis_thick]

Here guys argue about this...from a string NOT bass manufacturer

[Invalid or Expired Link Removed]

[Invalid or Expired Link Removed]

Here is one from a bass manufacturer
Quote from ESP:
String-Thru Bass Bridge
Whether you're seeking to increase overall string tension or just
"beef up" the response of your string attack, this feature is a
definite plus. If tighter string tension isn't your goal, these
bridges can also be strung through the top

 

[thepontif]

What part of it were you talking about?

 

[ehque]

Here guys argue about this...from a string NOT bass manufacturer

We've already shown that whatever a manufacturer says doesn't affect reality. There's enough marketing crap out there and i KNOW those guys are wrong if they are talking about static tension.

What part of it were you talking about?

I believe he's talking about this : "One advantage of this (2 piece bridge design) setup is the ability to have a longer total string length (which increases tension and clarity of fundamental)"

 

[thepontif]

D'Addario is obviously speaking subjectively. The static tension thing has been exhausted. Same string, same pitch, same SPEAKING length (transverse mode), same tension. Again, there can be a perceived difference in the resistance you feel from the string against your finger, but it's not necessarily a function of length, although it's been legitimately proposed that it could in a dynamic sense. But the static tension is the static tension at that pitch. If you want different tension for the same pitch and length you have to change the materials and hence the mass of the speaking portion of the string.

 

[Son of Magni]

...but no member of the PTG will ever agree with me...

There's a reason for that...

 

[thepontif]

What's that? Just because an "organization" subscribes to a theory certainly doesn't make it correct. On a large scale maybe it's a logical thing to do because it compensates for shortcomings on a lousy piano. But in a concert regulated and well maintained piano like mine, it doesn't work. The results don't lie. Having good ears is not a prerequisite for building or maintaining instruments. Or for joining organizations like the PTG. The only down side of this is that I only know one person who can put a good tuning on my piano and he doesn't live near by. In a good piano, stretching doesn't sound good. I'd suggest that people that believe it does believe it because they've never heard one that wasn't. The last PTG member who tuned my piano couldn't set a pin for cr@p. The unisons were out in a couple weeks. And, yes, it was rebuilt a year or so ago and all, including the pin block and strings, are pristine. I don't buy it...literally.