Sustain ?

[O. Apitius]

In order for loudness and sustain to both be increased, the efficiency of the system must be increased. That is, more string energy is converted to sound and less is lost to damping/friction. I don't remember what the numbers are, but I do know that the vast majority of string energy is lost to damping/friction, so we are only dealing with a small portion of the available energy from the strings when we tweak things to increase loudness or sustain, and even in a hypothetical system where we have improved efficiency as much as we reasonably can, there will still be a trade-off between loudness and sustain, but we can have more of both compared to a less efficient system.

The only way, even in principle, to increase BOTH the loudness and sustain, without violating the laws of physics, that is, would be to somehow convert the available vibrational string energy into acoustic radiation much more efficiently than the average mandolin does. Basically, that translates into finding a way to reduce the instrument's damping, which is where the available string energy is lost, if it doesn't go into sound production.

Bingo! I guess what I've been trying to say is that a statement along the lines of 'an increase in sustain can only be had at the expense of volume' assumes that the current design model has reached perfection.
I guess I'm one of those heretics who doesn't feel that the Loar signed instruments were the divine perfection of the arch top mandolin. Before I get burned at the steak, let me assure everyone that I have a tremendous amount of respect for those original F-5s. They got a phenomenal amount of details right in a relatively short time of about 20-25 years from first concept to final product. So here comes the but. I have seen graduation measurements of at least a dozen Loar signed instruments recorded by competent people and have had the opportunity to measure one personally, and I have to conclude that the graduations on these instruments were not particularily sophisticated.
On Loars own spec. sheet, he called for a thickness at the center of the top of "3/16'. Fin. 5/32" and a thickness at the re-curve of "1/8". Fin. 1/10" with little further instruction. From all of the data I have seen, this seems to have been roughly carried out but with no great regard for accuracy, smooth transitions or consistency. The area north of the bridge is especially noteworthy in this regard. Feel free to disagree and say this was all very deliberate but this is my take after having hand carved over well over 100 tops and backs.

Anyway, that is why I stated

"I'm not quite buying the idea that you can't have both above average volume and above average sustain in the same mandolin." (Italics added)

Yes, in a perfected system, volume and sustain would need to be balanced as part of a trade off but given as I believe we have not yet perfected all aspects of the arch top design, I believe that it is possible to give the customer a mandolin that is superior to most, in both of these aspects.

[Dagger Gordon]

I have to say that it came as a surprise to me several years ago in a thread here on MC that bluegrass mandolin players did not seem to particularly like sustain. I am the owner of a Stefan Sobell mandolin which has volume, tone and unbelievable sustain and I really did think that was what all good mandolins should have.

But it seemed not, judging from the responses made at the time. That discussion was so long ago that I doubt if I could find it now, so I would be interested to hear what people think about that, in case I am not quite remembering it correctly.

I can see that from this present discussion that there seems to be a trade-off between volume and sustain, and since bluegrass players don't necessarily want sustain anyway then it would follow that what a bluegrass player might consider a good mandolin (banjo killers etc) is not always what some of the rest of us might think.

Having said that, I also have a Collings MT which has volume, tone and pretty good sustain which I find to be very effective for Scottish music.

[Beanzy]

One unintended consequence of the mandolin build I had done by Phil Davidson has been a really good sustain when compared with other f hole Davidsons I’ve played. Very bell like & clear.
I had him build the neck with a 3mm carbon fibre block spliced through the centre of the neck before shaping, instead of having a truss rod. I assume the extra sustain comes largely from eficiency caused by removing damping that would normally occur in the neck by giving it a solid spar of carbon fibre from body to head, through the whole depth of the neck. The impression is getting something for nothing, but it’s really just not giving it away for no return. It did make me wonder if there could be a point where being too effecient would undermine the desired sound, or would we just head towards some lofty peak of tonal oerfection. So much of the ideal is in the taste & ear of the player though.

[Mandoplumb]

To me the difference in “modern” mandolins and traditional sound is sustain. Monroe, especially early on was by design very staccato Lawson on the other lets the notes ring longer. I think a lot mandolin makers have tried to make their instruments follow suit. I don’t see all bluegrassers wanting less sustain.

[DavidKOS]

edit....sorry

I had a bunch of comments and realized this thread is really about archtop mandolins only.

[Willie Poole]

I am a bluegrass picker and cannot understand why any one would want a mandolin with a lot of sustain, When I strike an open A string and then go to the next note say on the D strings I don`t want that A string note to still be ringing out...I always thought Ralph Stanley`s banjo did that. some notes were still ringing loud and clear when the went to a different chord...I know different people like different sounds and just thought I would express my thoughts on sustain...I have a Kentucky KM-956 that has great volume and very little sustain...Great for what I look for in bluegrass music...

Willie

[yankees1]

I am a bluegrass picker and cannot understand why any one would want a mandolin with a lot of sustain, When I strike an open A string and then go to the next note say on the D strings I don`t want that A string note to still be ringing out...I always thought Ralph Stanley`s banjo did that. some notes were still ringing loud and clear when the went to a different chord...I know different people like different sounds and just thought I would express my thoughts on sustain...I have a Kentucky KM-956 that has great volume and very little sustain...Great for what I look for in bluegrass music...

Willie

I have two Ellis's ( A and F5 ) for Bluegrass that I don't play much so wanting an Engelman top with more sustain for other types of music and style.

[JeffD]

Better tremolo = more sustain!

Hard to argue with that!!!

[JeffD]

edit....sorry

I had a bunch of comments and realized this thread is really about archtop mandolins only.

Yea, arch tops with ff holes. Oval hole arch tops seem to have more sustain, with volume, but less focus. At least in my experience.

[DavidKOS]

Yea, arch tops with ff holes. Oval hole arch tops seem to have more sustain, with volume, but less focus. At least in my experience.

I was going to comment about short-scale Italian style bowl or flat back mandolins with light gauge strings and the type of tone and sustain you get from them.

I realized I was not in the right thread!

[JeffD]

Well, to the point, the F5 is a design that has become popular because of its iconic sound, and over the decades even optimized a bit to better achieve that sound...

and the OP asks about modifying the F5 to get a different sound. Instead of looking into other types and styles of mandolin that may naturally produce the desired sound.

Its like asking for an Earl Grey tea that tastes more like coffee.

[yankees1]

Well, to the point, the F5 is a design that has become popular because of its iconic sound, and over the decades even optimized a bit to better achieve that sound...

and the OP asks about modifying the F5 to get a different sound. Instead of looking into other types and styles of mandolin that may naturally produce the desired sound.

Its like asking for an Earl Grey tea that tastes more like coffee.

Evidently, Northfield has become quite successful at producing a F5 Engelamn 5 bar top with sustain for those players that want more sustain and a mellow, quieter sound for other than Bluegrass !
I love the looks of a F5 but just want something a little different to play alongside my Ellis A and F5 red spruce mandolins ! Don't drink coffee but do drink green tea !

[Bertram Henze]

Its like asking for an Earl Grey tea that tastes more like coffee.

....or a vegetarian Black Angus Steak.

Can't beat reality.

[sblock]

Bingo! I guess what I've been trying to say is that a statement along the lines of 'an increase in sustain can only be had at the expense of volume' assumes that the current design model has reached perfection.

...Before I get burned at the steak...

Anyway, that is why I stated Yes, in a perfected system, volume and sustain would need to be balanced as part of a trade off but given as I believe we have not yet perfected all aspects of the arch top design, I believe that it is possible to give the customer a mandolin that is superior to most, in both of these aspects.

Burned at the steak (sic)? Burning at the stake is for witches! Burnt steak, on the other hand, is what our current president seems to prefer.

Anyway, I would have to agree that the archtop mandolin is by no means "perfected" -- nor, for that matter, has any musical instrument been perfected. However, after more than 300 years of development (Antonio Stradivari himself built a couple of mandolins that survive), we are not going to see mandolins get very much louder. A little bit? Maybe. After all, there is only so much you can do, provided that you stick to metal strings with a 13-14" scale length -- these are the things that provide the energy to drive the acoustics. Renowned luthier Joseph Curtin has been playing with lighter, stiffer woods to try to gain better volume (and better energy efficiency) in violins, and succeeded in making a violin top from balsa wood laminated top (!), with a thin veneer of spruce, that was louder than even the best available traditional violins. Maybe mandolin construction might benefit from his experiments? However, the far greater string tension on a mandolin would probably collapse any balsa laminate top, unless some way could be found to buttress it mechanically.

That said, the traditional archtop F5 design, first introduced in the Lloyd Loar era at Gibson, has probably reached very near its peak, in terms of the projected loudness and sustain, particularly with the latest generation of F5 instruments being produced by the top makers (and these cost $25,000 or thereabouts). In the latest top-end F5 models, the graduated tops are nearly as thin and stiff as spruce can be without risking structural collapse. And in such a situation, as we have discussed, there is an ineluctable trade-off between loudness and sustain because energy is conserved! Yes, you can have a bit more of one or the other, but not both. The only way to get both is to increase the acoustic efficiency. A different design -- something beyond the F5 -- will be required to do that, in all likelihood.

We know that it's possible to get louder with other designs, because we have all heard mandolin banjos (banjolins). But the tone of these things is awful, in my opinion -- and also the opinion of a great many folks here on the MC. The Holy Grail would be a wholly new mandolin design that maintains a "woody" tone and that has the equivalent acoustic efficiency of a banjolin (or even more). That instrument could be louder and have more sustain. But I would argue that the F5 design is more or less tapped out at this point. There are F5s being made these days that sound just about as good as -- and maybe a bit better than -- Loar-signed Gibson F5's from 1922-24, but they are not remarkably louder instruments, nor do they exhibit remarkably more sustain. Therefore, I do not anticipate significant advances along these lines. Other lines might be more promising, however, so experimentation continues. But in the end, you still have only so much energy in a plucked string.

[fscotte]

I see no mention of how the top and back work together as a possible reason for sustain, or lack thereof. I do know that Peter Coombe has done some testing and found that sustain can be increased, to the point of unplayability, by adjusting its stiffness to certain chladni intervals of the top.

Perhaps he'll jump in as well.

[yankees1]

....or a vegetarian Black Angus Steak.

Can't beat reality.

Ever tried a black bean burger ? Healthy and great tasting !

[Loubrava]

I see no mention of how the top and back work together as a possible reason for sustain, or lack thereof. I do know that Peter Coombe has done some testing and found that sustain can be increased, to the point of unplayability, by adjusting its stiffness to certain chladni intervals of the top.

Perhaps he'll jump in as well.

I was wondering what effect back & side woods have on the sound & was going to post a thread on it or do search but since you brought it up I'll ask it here. I've always payed more attention to the back thinking a nice tight book match maple back was better for tone than some loose grain backs or a mahogany back. I played 2 different Webers both had same spruce top one had maple sides and back the other had mahogany and they sounded different I wasn't comparing sustain just the overall sound. I thought it was the difference in the woods but after reading this thread maybe it wasn't. Or is sustain & tone a completely separate thing ?
Lou

[sblock]

I was wondering what effect back & side woods have on the sound & was going to post a thread on it or do search but since you brought it up I'll ask it here. I've always payed more attention to the back thinking a nice tight book match maple back was better for tone than some loose grain backs or a mahogany back. I played 2 different Webers both had same spruce top one had maple sides and back the other had mahogany and they sounded different I wasn't comparing sustain just the overall sound. I thought it was the difference in the woods but after reading this thread maybe it wasn't. Or is sustain & tone a completely separate thing ?
Lou

When a mandolin string is plucked and released, the string is set into motion and the instrument responds by mechanically vibrating, transmitting a portion of that vibratory energy to the air around it, which emerges as the sound we hear. After a short time (less than a few seconds), due to damping effects in the instrument -- but also, to a lesser extent, in the string itself and in the surrounding air -- the initial energy in the string is dissipated in the form of heat, and the sound stops. The frequency content of the sound that emerges into the air gives rise to "tone." The duration of the sound that emerges gives rise to "sustain." The amplitude and direction of the sound field that emerges give rise to a perceived "loudness." So these are all different attributes of the same thing, and they are all intimately coupled.

The back, sides, and top of the instrument (including any bracing), plus the the bridge and, to a lesser extent, the neck and other parts, are all part of a resonant system that helps to generate and project the sound in air from the string energy. Put another way, the job of the instrument is to couple the string energy to the radiant sound field as efficiently as possible. The volume and shape of the instrument's air cavity, and also the size, area, and location of any ports (sound holes) form an integral part of that system, too. And finally, properties like string tension, the downbearing force on the bridge (neck angle), the acoustical impedance of the bridge, and so on, also exert their effects. Because these things all work together, it is not very meaningful to assign "tone," "sustain," or "loudness" to any single component, nor to any pair of components.

That said, it is possible to perturb a given instrument's sound significantly by making fairly minor adjustments to some of the major contributors. These types of adjustments include, among other things: different wood selections, different types and sizes of bracing, different air cavity sizes, different necks, different sound holes, different bridges, different carving graduations, etc. That last one is especially important. Remember, it's all about (1) mass, (2) stiffness, and (3) damping.

So yes, the top and back work jointly to produce many of the major "woody" resonances of the instrument. And additional resonances come from the air cavity itself (Helmholtz resonance), the ports, and from interactions of the top and/or back and the air. If the top and back happen to be closely matched in their characteristic frequencies, this can sometimes lead to a sharper resonance peak for the entire instrument at a particular sound frequency. This outcome is usually considered to be undesirable, because this same resonance robs all the other frequencies of energy (remember: there is only so much energy available, and it has to go somewhere!), and produces a louder "woof" near a single note. That same "woofy" note will also ring out for longer, giving additional sustain. Anyone seeking to produce an instrument that responds well over a wider range of frequencies will therefore try to avoid loud resonances of this type! One popular way to do this is to "tune" the top and back to slightly different notes before assembly, but even this is no iron-clad guarantee (!), because the resonances of the assembled instrument, where the top and back are joined to the sides, are NOT simply related to the resonances of the unattached top and back! Regardless, the general aim is to spread the string energy out over an entire midrange of notes. But this is a fairly simplistic way of thinking about things. The body and wood produce an entire SPECTRUM of frequencies when excited, and this spectrum pretty much defines the tone (timbre) of the instrument, as well as the loudness.

The bottom line: sustain, loudness, and tone are not separate quantities. In fact, they are very intimately linked. And yes, the top and back work jointly to contribute to the sound, but they are not the only determinants.

[Loubrava]

Thanks sblock, nice explanation even I can grasp that ! No wonder the guy who’s building my mandolin tells me “no matter what I do I won’t get 2 mandolins to sound exactly alike even if built from the same piece of wood” I never had much interest the physical make up of an instrument until I commissioned the one I’m getting interesting stuff.
Lou

[peter.coombe]

A big sustain means the Q of the system is high, i.e. damping is low. As already pointed out, the mandolin system is complex. What will give you a big sustain or a short sustain I don't really know, but much of what has been said here is over simplistic. Thin top and backs or thick tops and backs don't seem to make any difference. Stiffness and mass are separate properties from Q. My latest smaller bodied oval hole mandolins are carved thinner but they seem to sustain more. Different woods don't seem to make a great deal of difference either. I think it may be the way the various body and air modes couple, hence my observation that if the main air mode and the longitudinal neck mode correspond, then you tend to get a huge sustain. It is really mostly speculation, we don't really know. All I know is that all my oval hole mandolins have a big sustain, the A5 models tend to have less, but more than most other builders. My flat top mandolins can have massive sustain, so that blows away the theory that thinner tops will have less sustain. You can increase volume by decreasing mass, which is what happens in flat top mandolins. The top is usually lighter than a carved top so you get more volume. Using carbon fibre can get you into another world in terms of efficiency because of the high stiffness to weight ratio, but it is a balancing act. Make the top too stiff and light with carbon fibre lattice bracing and the mandolin will sound very loud and obnoxious.

[Larry Simonson]

this is one of the finest discussions of mandolin mechanics I have read in many years of reading this forum. Thanks to all.

I have a question- Can Q, mass, and stiffness be independently measured on existing instruments?

[Dagger Gordon]

Make the top too stiff and light with carbon fibre lattice bracing and the mandolin will sound very loud and obnoxious.

'Very loud and obnoxious.' I will remember that.

Thanks for a fascinating and very concise contribution, Peter.

But volume is important too, as anyone who has tried to play Scottish or Irish music in a noisy pub on a mandolin will tell you, and indeed I have always been a bit surprised at the ability of bluegrass pickers to cut through in a bluegrass band, or for that matter a soloist like Avi Avital to project in front of an orchestra.

[Ivan Kelsall]

Refering back to Oliver Apitius's post - i read on here a while back in another thread re. 'Loar graduations',that the tops on some of them were pretty rough. The same thread also mentioned that the graduations seemed to be a bit hit & miss - possibly due to individual piece of wood differing one from another ?. However,there seemed to be nothing 'immaculate' about the carving.

Regarding sustain/volume - the one Oval hole mandolin that i once owned,a Weber "Beartooth" "A" style,had tremendous volume & sustain. My Weber "Fern" has volume,but it's sustain is pretty minimal. However,for Bluegrass music,it fits the bill regarding what i want 100%. So,going off my own experience,a mandolin can have both volume & sustain,but maybe only within limits ?.

David - If you visited my local Foilk club,you might also be amazed at the total inability of a mandolin to cut through - a Tenor banjo / a Piano Accordion / 2 Fiddles & a Bodhran !!,
Ivan

[Dagger Gordon]

David - If you visited my local Foilk club,you might also be amazed at the total inability of a mandolin to cut through - a Tenor banjo / a Piano Accordion / 2 Fiddles & a Bodhran !!,
Ivan

I'm afraid I wouldn't be amazed at all, Ivan - I see it all the time. There is a reason mandolinists play tenor banjo at a session.

[fscotte]

Regarding the rough carving on Loar plates.

What evidence is there to suggest that a smoothly transitioned graduation is any better than one that is rough carved? The plate will move based on its overall mass and stiffness. It does not seem to matter if it is a bit thicker here or a bit thinner there. Any extra thickness simply adds to the stiffness and vice versa.

I guess what I am saying is that we seem to be forcing physics to fit our idea of what an ideally carved plate should be, when the reality is that the plates don't care. They will still move in their normal modes of motion based on their current mass and stiffness.

Putting braces in asymmetrical positions would be an example of asymmetrical mass and stiffness. The plate doesn't care, or should I say, physics, doesn't care how they are arranged. The plate still acts based on its overall mass and stiffness.