The neck's contribution to tone quality

[Ivan Kelsall]

From Peter Jenner - " What's brown and sticky ? -...a stick.". Oh Peter !,you are a one !!!!. You've lived upside down for too long mate !.
I'm not sure that i'd go so far as to say that the neck contributes 'directly' to the sound from any instrument,but they certainly do vibrate in concert with the main body of the instrument. Both my mandolins feel 'alive' when i play them & it's a great feeling, as though they really are responding fully to my efforts. My Stelling banjo neck has a life all it's own when i play it,it really does vibrate,& again,it's a nice feeling rather than having a totally inert instrument (as well as player !). I suppose if the neck of an instrument does vibrate (resonate),then it must have a resonant frequency.However,i think that it would be hard to measure this frequency, totally divorced from the resonance of the instrument as a whole. I suspect it would be sub-sonic,but nevertheless,it would have some influence on the resonance of the 'whole' & a such affect the sound of the 'whole',as has been stated above.
I understand what Shelby says as well. The strings & bow/bowhair must impart vibrations of their own to the 'whole' set of vibrations going on, which are then transferred to the body of the Violin (for example) via the bridge,which itself will have it's own resonant frequency to add to the mix. Change any one of these factors & you change the 'whole',otherwise all the experiments into 'acoustics' in instruments over centuries, would have been pointless - i think i'll buy a Trumpet !,
Ivan

[Dave Cohen]

From Peter Jenner - " What's brown and sticky ? -...a stick.". Oh Peter !,you are a one !!!!. You've lived upside down for too long mate !.
I'm not sure that i'd go so far as to say that the neck contributes 'directly' to the sound from any instrument,but they certainly do vibrate in concert with the main body of the instrument. Both my mandolins feel 'alive' when i play them & it's a great feeling, as though they really are responding fully to my efforts. My Stelling banjo neck has a life all it's own when i play it,it really does vibrate,& again,it's a nice feeling rather than having a totally inert instrument (as well as player !). I suppose if the neck of an instrument does vibrate (resonate),then it must have a resonant frequency.However,i think that it would be hard to measure this frequency, totally divorced from the resonance of the instrument as a whole. I suspect it would be sub-sonic,but nevertheless,it would have some influence on the resonance of the 'whole' & a such affect the sound of the 'whole',as has been stated above.
I understand what Shelby says as well. The strings & bow/bowhair must impart vibrations of their own to the 'whole' set of vibrations going on, which are then transferred to the body of the Violin (for example) via the bridge,which itself will have it's own resonant frequency to add to the mix. Change any one of these factors & you change the 'whole',otherwise all the experiments into 'acoustics' in instruments over centuries, would have been pointless - i think i'll buy a Trumpet !,
Ivan

Necks have not just one resonant frequency, but many resonant frequencies. My first post in this thread was about the first two resonant frequencies in a mandolin and a guitar. Not only did I already measure those frequencies, as well as others, but I also imaged the motions with interferometry. The term "subsonic", usually implies frquencies outside the limits of human hearing. 115 Hz and 400 Hz are well within the limits of human hearing; The low C on a manodcello or 'violoncello is 65 Hz. However, the amplitudes of the neck motions are frequently about an order of magnitude smaller than the amplitudes of plate motions in the instrument body. Also, the neck motions do not by themselves couple directly with an air resonance, At least not as far as I have observed.

I did the above experiments on a single mandolin body with two interchangeable necks. One was a conventional neck - w/ a conventional adjustable truss rod and no CF reinforcement, The other neck was a hollow CF shell, about 50% stiffer and 80 grams lighter than the conventional neck. There were observable physical differences between the two necks. Also a difference in sound that I think most listeners would be able to discern. It should be kept in mind that the two necks described are profoundly different physically. In the case of a true double blind test with two conventional interchangeable necks, say one made of walnut and one of maple, I would be very surprised if anyone were able to distinguish between the two at any level better than wild guessing. For one thing, maple and walnut have similar average densities and similar average Young's moduli.

http://www.Cohenmando.com/

[Willie Poole]

So I guess the final answer is that the necks can make a difference but most of us would not be able to hear it, is that about right? Not that I really care because I am no builder bit I do like to absorb as much info as I can about what makes mandolins sound like they do...

A good post and interesting to say the least....

[bratsche]

Just FWIW and for your info, here is a site that appears to "rate" various exotic hardwood species along a tonal spectrum from warm to bright, for use in guitar necks.

bratsche

[mandobassman]

The fact that many players attach their electronic tuners to the headstock tell us that the neck is indeed a moving part of the instrument and thus is involved in the total sound producing mechanism.

You can attach you electronic tuner to the strap and it will work just fine. Is that a "moving part of the instrument" as well?

[fscotte]

Anything that moves makes sound. Strap included. Even the legs of a spider makes sound.

[Hendrik Ahrend]

On a guitar at least, the maple fretboard gives a brighter snappier tone. Rosewood is warmer.

... and an ebony fretboard sounds again warmer, I found. I've never played a Martin D-21 (Brazilian rosewood fretboard and, well, bridge) that sounded like a D-28 (ebony fingerboard & bridge); played many of both.

[hank]

Thread wake up time. I'm back thinking about necks again and have some new thoughts to turn over among you. I look at the neck and its connection to the body more along the lines of vibration transmission between the the string ends I'm sure I'm over simplifying the reality of the mechanics at work here but wouldn't a tuning forks handle act in a similar way. The handle is vibrating as well as the prongs as they move alternately in a lateral motion. The low amplitude stronger vibration in the handle is not dampened by your hand while the the high amplitude weaker vibration of the prongs are easily dampened. This is why the transmission of vibration from the fork prongs is through the handle to a secondary sound radiator. The low impedance pathway between the alternating cycles of prongs in the handle increases the strength of the driving force that is available at it's base. Most of us think of reducing resistance in the vibration transmission from the bridge to the top plate but poor fitting connections between other parts with soft curing glues increases the impedance of the nut/fret neck circuit of vibrations back to the body of the instrument completing the low impedance path. Even though the top plate is the main radiator of sound with it's air coupling to the back plate it's best performance is dependent on the other parts staying in communication with it in a low impedance circuit.

[Tavy]

Anything that moves makes sound. Strap included. Even the legs of a spider makes sound.

I'm going to disagree with that somewhat, and with Hank in post #33:

I'm firmly in the camp that the only thing you want moving, are those parts that actually produce sound: and that means the top and to a lesser extent the back. Everything else would ideally be the proverbial "immovable object", if it transparently transmits vibrations to the top and back, that's fine and dandy, but ultimately vibration in all the other parts are really just creating waste heat.

Discuss

[kkmm]

but ultimately vibration in all the other parts are really just creating waste heat.

OK, that should nailed it. "vibration in all other parts" means some energy are wasted in these "immovable objects" instead of making the top & back vibrating. And this does reduce the sound volume (and the tone changes either for better or worst).

[Willie Poole]

Some years ago I read an article that said that Geoff Stelling and other builders would clamp different size pieces of wood on the head stock of banjos to find the best sound they would produce and then make the neck and head stock with that amount of wood because they believed that sound does travel out through the neck and to the peghead.....I had never given any thought to this since I don`t build any instruments but just thought I would throw this in and maybe add some insight to the OP`s question....As I said I read it somewhere and don`t know first hard if it is a fact...

Willie

[fscotte]

I'm going to disagree with that somewhat, and with Hank in post #33:

I'm firmly in the camp that the only thing you want moving, are those parts that actually produce sound: and that means the top and to a lesser extent the back. Everything else would ideally be the proverbial "immovable object", if it transparently transmits vibrations to the top and back, that's fine and dandy, but ultimately vibration in all the other parts are really just creating waste heat.

Discuss

If it moves, it moves air molecules, which creates pressure within the air. That creates sound, whether you can hear it or not is the question. If you feel any part of the mandolin vibrating, then it's creating sound. Every mandolin I've ever played vibrates as a whole, with no dead parts, so the whole thing is moving air molecules. Again, whether you can hear it or not is another issue.

[hank]

I have noticed that better built mandolins seem to not only have better richer tone color but noticeably better sustain unless they have been set up with extreme break angles. Years back I had a mandolin improve in both volume and sustain after adding tension at the adjustment nut that had little to no tension on it. The real wasted energy is that absorbed into loose parts and bad connections of parts. This is where the resistance can be reduced from the pulses running through the circuit of vibration. As long as the amplitude of the vibration is low there is little effect on the air to produce much sound but the timbre and sustain of the existing tone chamber are sometimes improved unless there is a problem with the frequency causing unwanted harmonic or sympathetic vibrations in the circuit. The ideal situation is management of the vibration not suspension of it. My background in RotorWing systems and airframe taught me this a long time ago. Accelerometer study often revealed movement of known nodes after repair changed the mass and stiffness of the structure only in a small area. You had to look at the system of vibration as a whole and their effect on each other not the individual components working in isolation.

[Marty Jacobson]

I have noticed that better built mandolins seem to not only have better richer tone color but noticeably better sustain unless they have been set up with extreme break angles.

Does 21+ degrees count as extreme? :-)

[fscotte]

Marty, everyone I've seen with your mandolins appear to be playing effortlessly and enjoying the experience immensely.

[Marty Jacobson]

Marty, everyone I've seen with your mandolins appear to be playing effortlessly and enjoying the experience immensely.

Let's just say I made them an offer they can't refuse.

[hank]

Thank you Marty, I was hoping to hear from you in this discussion. I respect your opinion and thoughts about what you have learned taking a path less traveled. I am always pleasantly surprised by you artistry and unique approach to create a great mandolin. My observation of the effect of greater break angles is of F5 copies looking for more cutting power in a Bluegrass chest thumpathon. Your creations are pretty far from that mold. My desire is to not find fault with your designs, break angles or customer satisfaction but to get knowledgeable forward thinking luthiers like yourself to help us understand what truly is important about putting these parts into a unified whole. If you think your neck parts are void of this circuitry of vibration and are only active at the business end of the bridge, top and rear plate with the rest of the mandolin in a null without continuity. I'm listening.

[Marty Jacobson]

Thank you Marty, I was hoping to hear from you in this discussion. I respect your opinion and thoughts about what you have learned taking a path less traveled. I am always pleasantly surprised by you artistry and unique approach to create a great mandolin. My observation of the effect of greater break angles is of F5 copies looking for more cutting power in a Bluegrass chest thumpathon. Your creations are pretty far from that mold. My desire is to not find fault with your designs, break angles or customer satisfaction but to get knowledgeable forward thinking luthiers like yourself to help us understand what truly is important about putting these parts into a unified whole. If you think your neck parts are void of this circuitry of vibration and are only active at the business end of the bridge, top and rear plate with the rest of the mandolin in a null without continuity. I'm listening.

Hi Hank, I didn't take anything you said as disparaging. I have no idea what the neck does to the tone, but my feeling is that whatever it is, it's somewhere between negligible and subtle. I do change break angles to get different kinds of tonal properties, but I think that has to do more with the arching than the neck itself.
As far as my process goes, the neck is a handle - it has to perform an ergonomic function, not an acoustic one. I know that must be an oversimplification, but it's so far down the list of things to fiddle with that I suspect it'll stay that way for me.
The neck is actually one of the things I've spent the most time on, but it's all about manufacturing, stability, and ergonomics. It never even occured to me to change something about the neck in pursuit of a certain tonal trait (aside from break angle to allow a swoopier plate or less break angle for a flatter plate).

[Polecat]

I'm not a builder, but I've read this thread with great interest. How much the neck influences the perceived tone is, I suspect, impossible to quantify, and I believe that Marty's comment that

it's all about manufacturing, stability, and ergonomics

is pretty much right. On the other hand, what is beyond doubt for me is that the mass of the neck affects sustain to a very great extent. Fender markets a device called a fatfinger, which certainly works to increase sustain, which you can easily check without buying one - just clamp a G-cramp to the headstock and hit the open strings - the difference is quite surprising (it upsets the balance of the instrument pretty badly, too, so it's not very practical). I presume that it works by increasing the inertia of the whole neck, so that more energy stays in the vibrating strings. Consequently, it seems reasonable to me that a chunkier neck made of a denser, stiffer wood would have a similar effect.

[sblock]

It seems to me that many of the responses in this thread may be barking up the wrong tree. Of course, virtually every single part of the mandolin contributes to its overall tone quality, to some degree or other. All parts add some mass, and perhaps also a bit of stiffness and damping. And the mass, stiffness, and damping -- along with physical coupling among the separate parts -- are what give rise to mechanical vibrations, and therefore to the sound and timbre. The proper question to ask is HOW MUCH does the neck contribute, relative to the other major wooden parts, like the top, back, sides, and bridge. And the answer, which I really can't imagine is very controversial among luthiers, is that the neck contributes very little to the projected sound, especially compared to the top, back, sides or bridge. The qualities of the top, back, sides and bridge matter a whole lot more, in fact.

Will a more massive neck affect sustain? Yeah, a bit. But the sustain mostly comes from how the string energy gets shared with the body, and with the damping associated with its various resonances. So, does the neck participate in that energy sharing? Yeah, quite a bit (since it holds the string taught!), but that part of its function is similar from one neck to the next. There is just not a lot of "room for maneuver" in neck acoustical properties. What matters much more for the mandolin neck are its ergonomic properties (size and shape under the hand), as others have already expressed so well.

Put another way, if you want to improve the sound of a mandolin, there are other, much better ways to go about doing it than adjusting the neck wood/shape, or neck-body joint, or fingerboard. There is just not much gain to be had there. Not so for the other wooden parts: the top, back, sides, and bridge. These things exert a much more dramatic effect.

[chris storz]

^^That. Like just about any other stringed instrument the ergonomics of the neck have a far larger affect on the sound than the actual "acoustical properties" of the wood that the neck is made of, because the biggest determiner of sound is in your fingers. How the neck requires you to angle your fingers or how much force you have to exert to get a good tone. These factors are what matter.

[Larry Simonson]

Most everyone who has had a string break knows that the instrument's other strings will go sharp. I believe this result is due to the relaxing of the entire instrument and the extent to this sharpening is related to the overall flexibility of the instrument. Perhaps the stiffness of the neck is a major player. The extent of sharpening is a objective measurement of a given instrument and I think it would be interesting to get a data base on many instruments and see if there is any correlation to tone quality as perceived by an experienced listener and the flexibility of the instrument. One can get somewhat of a measure of flexibility using a decent tuner to measure how much sharpening occurs when one takes the tension off a string or two, starting with an in-tune instrument.

[hank]

Maybe the reason necks seem so boring to many builders is that standard practices for successful construction of them and body connections have been worked out for a very long time. Why mess around with something if it isn't broken? As sblock and Marty point out the effect to the instrument is small if you follow the successful methods standardized today from great luthiers from the past. Following commonly used practices, wood choice and eccentricities of shape on necks are more structural/ergonomically prioritized than sound shaping. I understand this and am not suggesting anything other than contemplation of why tight neck connections and particular glues are desirable in a build no matter what wood choice is made.
As an example of departure from stereotypical thinking is Nigel Forster's cantilever neck arch top guitars. His bold departure from standard guitar construction in this model is a good visual representation of high energy low amplitude vibration transferred to the secondary high amplitude radiating acoustic moving plate. Nigels method of driving his bridge/top plate is very similar to holding the ball at the base of a tuning fork to a tabletop to hear the low amplitude vibration. The neck like a complete solid body electric guitar bolted to an acoustic guitar with a single point of vibrational energy transfer.

[theCOOP]

A response to the original post:

Imagine if balsa wood cod stand up to the stress of the strings...how do think the instrument would sound?

I'm forming my opinion as I type this. I don't think the sound would be as complex as with a hardwood neck. Imagine if tin foil was a suitable medium for your work truck's frame, how it would sound and feel coming down the road.

I just think there's something to be said for mass-damping

[Tavy]

A response to the original post:

Imagine if balsa wood cod stand up to the stress of the strings...how do think the instrument would sound?

Neapolitan bowlbacks and many early flatbacks have necks made from laminated spruce with a hardwood veneer wrapped around. They're as light as a feather and don't sound noticeably better/worse than similar later instruments with heavier hardwood necks. As others have said, don't over-think it, it's a handle guys