Siminoff's Thoughts On Accoustics

[Mark Gunter]

My current readings have been various articles from The Big Red Book Of American Lutherie, Vol. 2, 1988 - 1990 and The Ultimate Bluegrass Construction Manual by Roger Siminoff, 2004. I've been interested in both these volumes for separate reasons. I've long intended to purchase the Siminoff handbook for the construction methods; the American Lutherie volume contains articles written by Thomas D. Rossing that Dr. Cohen recommended in another thread here. I was unable as yet to purchase either of these volumes, but eager to study them, and so I have them for a short time thanks to inter-library loans.

I first tackled the Rossing articles, and found them very interesting. I'm learning a great deal about the behavior of soundboards, ribs, backplates and air volume of stringed instrument bodies, as well as test methods and models used in collecting data for those articles. Lacking an education in physics, much of what is covered in the presentation of data is "over my head" as they say, and requires some study of other texts along with them.

Finally today, I turned to the Siminoff book, and was immediately impressed with the imprecise and sloppy way he uses the terms "amplify" and "amplification" in his first chapter, which deals with acoustics. In short, he uses the terms in precisely the way that I used them here before, much to the chagrin of the physical scientists and even some of the more opinionated luthiers here. It was the realization of this that moved me to post this account of my current readings, because although I have decided to not use the terms in the way that I formerly have in order not to cause confusion in discussions that are likely to attract physicists, I do in some small way find satisfaction in knowing that there are folk like Roger Siminoff who hold to a similar understanding of acoustics. In one example, he mentions the difference between the sound that reaches the eardrums from a lone tuning fork, as opposed to a tuning fork that is coupled with a piece of wood or a hollow chamber. The difference in volume of the sound we hear is due to an increased amplitude of the sound wave that reaches our ear, and in that sense the sound has been amplified (though no energy has been added).

In Roger's words:

Sound energy can be amplified. The small vibrations of musical strings become loud components when the strings are connected to the soundboard.
. . .
When the soundboard vibrates, it moves masses of air in front of and behind it, causing layers of compression and rarefraction to propogate from the instrument. When we place a carefully constructed soundbox behind the soundboard and perforate the soundboard's surface with carefully sized and tuned apertures (f-holes), we not only amplify the strings' energy, but we can add "voicing" to it and can control the richness and "color" (timbre) of the sound.

Like the tuning fork in the earlier example, the strings generate sufficient energy, but lack the surface area to create sufficient masses of air movement for us to hear them, and thus we need to connect them to something larger such as a soundboard.

My point in sharing this is NOT to denigrate the objections of the scientists here who wish us to limit our use of amplify to a narrower meaning, nor to offer Roger Siminoff as an authority whose example we should follow. What is my point?

Well, in a recent thread, a couple posts went so far as to intimate that such a loose usage of the word is an inherently wrong usage of the word in the English language, and I am offering this published usage to refute that notion. In my own mind, and evidently in Roger's as well as other folk who post here, it can be legitimate usage when describing the enloudening of an object by any means whatsoever. If a sound is louder to the ear, the sound wave that reaches the ear has greater amplitude.

While I think it is reasonable to expect that we all use words in the same way in order to avoid confusion, I also believe it more important to try to understand what a person intends when he or she uses terminology in a way that differs from you.

[Mark Gunter]

My apologies, this was meant for the builder's forum

[Mandoplumb]

I still think if it gets louder it is amplified and I'm sure I'm not alone in that. I can also understand someone trying to make people use the correct word. I do plumbing work and my pet peeve is folks calling a water heater a hot water heater. I used to tell them hot water don't need heating, but I've realized that I'm fighting a losing battle, so if you call it a hot water heater I'll let that go and I'll call getting louder amplification how ever it's done. I think in both situations we'll understand each other.

[peter.coombe]

Roger Siminoff is not a scientist. Much of what he says about tap tuning has been described as "Star Trek science" by some on this forum. Nuff said.

[fscotte]

Roger does deserve a certain amount of respect for his quest to decipher why Loars sounded so good, and what process they used to get to that sound. Since none of us know, at least Roger sorta opened that door a bit for us. He did lose me though when he describes his experiment where he put his hand to the back of a Loar soundboard and felt it vibrate at 256 Hz, then proclaimed that Loar backboards were tuned to 256 Hz! It showed a complete lack of understanding of how mandolins work when assembled.

Roger is in what we call between a rock and a hard place. He's spent decades and wrote countless books on tap tuning and what not, so he simply cannot deny that it works at this point. He does make some fine mandoln parts however.

[Marvino]

It showed a complete lack of understanding of how mandolins work when assembled. ............................

Roger is in what we call between a rock and a hard place. He's spent decades and wrote countless books on tap tuning and what not, so he simply cannot deny that it works at this point.

I think Roger Siminoff deserves more then a certain amount of respect.
Do you need to agree with everything? No. But he has contributed more to the world of mandolin building then anyone else I know.
I think Roger has a pretty good understanding of how mandolins work when assembled.

If Roger is in between a rock and a hard place, then so was Lloyd Loar. Last I noticed, Loar signed Master Models are the standard all modern mandolins strive/try to imitate.

Of course this is all IMHO

[Dave Cohen]

Roger Simiinoff certainly deserves some credit. His two editions on building a bluegrass mandolin were the first, and for a long time, the only references on building arch top mandolins.

My problem with Siminoff is that he doesn't know where to draw his own boundaries. His academic training was in industrial design. I am not sure from that just how much undergraduate physics and mathematics coursework he actually took. He certainly has not taken any graduate level courses in either physics or mathematics. He has never published any papers on acoustics in a peer-reviewed journal. Despite those limitations, his bio in his book on tap tuning describes him as "...one of the foremost authorities on musical acoustics." I have a copy of that book (In fact, he sent it to me). It is clear that the tap tuning about which he wrote is a collection of empirical lore on a ritualistic procedure for the final carving of plates, interspersed with some very incorrect and even nonphysical interpretations of what is going on. He does not, or at least he did not, understand the significant differences in the modes of motion of free plates and plates clamped at their edges, as in assembled instruments. He listed some classic references, including the famous Morse text on acoustics, but it is clear from his narrative that he either did not read the Morse text, or else he did not understand what he read. At the time he wrote his tap tuning book, he did not know if the frequencies of the free plate motions would be the same for the plates in an assembled instrument, or even if the motion would be the same for free plates as for plates clamped at their edges. But those things have been known for over a hundred years, dating back to Helmholtz' time or possibly even before that. Mind you, that is not some arcane detail; rather, it is fundamental to an understanding of how instruments move. Since a lot of people have read Siminoff's books, there are a lot of people who have been seriously misled by him, both about his qualifications and about the motions of plucked string instruments. It is clear to me that Roger Siminoff would not know how to solve a differential equation if one hit him in his hindquarters, yet he seems content to promote himself as someone who is an authority on musical acoustics. If he would stick to describing his processes as he executes them, and stay away from attaching bogus physical interpretations to them, I would have no problem with him whatsoever.

Archtop Guitar luthier Bob Benedetto said it well in his book. If a customer asks you something about how an instrument works, don't make something up, even if it sounds 'reasonable' to you. That is a disservice both to your customer and to yourself. If you don't know definitively how the thing works, say that you don't know. I will respect you for that, and I hope that your customer will as well.

[sunburst]

...If you don't know definitively how the thing works, say that you don't know...

That is one of my favorite things to do sometimes.
I remember once, a customer looking at the underside of a completed mandolin top that had not been glued to the rim asked: "What do those 'tone bars' do?". I thought for a few seconds and then I said: "I don't know". The look on the customer's face was quite amusing to me. Somewhere between shock and puzzlement that I didn't have a ready answer describing vibrations traveling along the braces and doing specific things to various parts of the top. Basically the customer expected me to make something up!
Anyway, after I said "I don't know", I said here's what I do know, and before I got too far into the static function as beams to support bridge pressure, the dynamic function of locally stiffening parts of the top to potentially modify mode frequencies, and being a means for the builder to conveniently adjust stiffness vs mass of the top, the customer moved on to another question. He didn't really want a real answer, he wanted something that sounded romantic, enigmatic and artistic. Perhaps I should have said; "They amplify the sound"!

[Mark Gunter]

I've read in several threads here details about the "tap tuning" of free plates, in which you have shed considerable light on the subject. I've learned a lot just by reading some of the old threads you and others have commented in. My interest in the Siminoff handbook is purely from a practical construction point of view. I posted this when I picked up the manual for the first time and noted his use of the word amplify on page three. He uses that word to express an increase of loudness when a sound chamber is used to enlouden a note, which is not a precise way of describing the physics, but (my point) not an incorrect use of English language. My understanding of sound was that loudness is a function of the amplitude of the sound wave that reaches the ear, and that is why I formerly used the term amplify loosely. I do not quote Mr. Siminoff as an authority, but as an example of a looser usage of the word amplify - because while I understand the need for agreeing on terms for clarity's sake, I do not believe it is inherently wrong English lexical usage of the word amplify to mean, "to make louder". A fine point, but sometimes it seems the scientists here can push too far.

[Oliver A.]

ooops.

[Mark Gunter]

Since a lot of people have read Siminoff's books, there are a lot of people who have been seriously misled by him, both about his qualifications and about the motions of plucked string instruments.

I've already encountered problems in his explanation, in this manual p. 5, of the forces brought to bear on the bridge by the plucked string. His explanation appears perfectly reasonable, but falls short compared to Rossing's explanation in An Introduction to Guitar Acoustics at figures 4 and 6 and accompanying text. Siminoff appears to underestimate the effects of the transverse forces and declares that "The soundboard of an acoustical guitar with a fixed bridge is driven almost entirely by longitudinal vibrations." If I hadn't read Rossing I would have taken him at his word on that.

[Hendrik Ahrend]

That is one of my favorite things to do sometimes.
I remember once, a customer looking at the underside of a completed mandolin top that had not been glued to the rim asked: "What do those 'tone bars' do?". I thought for a few seconds and then I said: "I don't know". The look on the customer's face was quite amusing to me. Somewhere between shock and puzzlement that I didn't have a ready answer describing vibrations traveling along the braces and doing specific things to various parts of the top. Basically the customer expected me to make something up!
Anyway, after I said "I don't know", I said here's what I do know, and before I got too far into the static function as beams to support bridge pressure, the dynamic function of locally stiffening parts of the top to potentially modify mode frequencies, and being a means for the builder to conveniently adjust stiffness vs mass of the top, the customer moved on to another question. He didn't really want a real answer, he wanted something that sounded romantic, enigmatic and artistic. Perhaps I should have said; "They amplify the sound"!

Good post John, thanks.
All those with a tendency to demand a perfect analytical, rational explanation may be interested in this:

http://hbr.org/2014/06/instinct-can-...tical-thinking

[Bertram Henze]

...discussions that are likely to attract physicists...

[Jim Hilburn]

Has anyone ever seen or heard a Siminoff mandolin?

[David L]

I still think if it gets louder it is amplified and I'm sure I'm not alone in that. I can also understand someone trying to make people use the correct word. I do plumbing work and my pet peeve is folks calling a water heater a hot water heater. I used to tell them hot water don't need heating, but I've realized that I'm fighting a losing battle, so if you call it a hot water heater I'll let that go and I'll call getting louder amplification how ever it's done. I think in both situations we'll understand each other.

If you have a tank-style heater, most of the time you ARE heating hot water. We have a tankless water heater, which DOES heat cold water.

[David L]

Touching a tuning fork to a hard surface does not amplify the energy of the vibration of the fork. It does amplify the volume of the sound waves in the air. Since the energy is not amplified, the energy dissipates faster. So the sound is louder, but lasts a shorter period of time.

[DataNick]

Has anyone ever seen or heard a Siminoff mandolin?

I'll comment here before this roast Roger thread gets shut down: I have both played and listened up close & personal to Roger Siminoff's personal F5. It was easily one of the 5 best bluegrass mandolins I've ever heard...it just had it all in spades, a real monster!

[Jim Hilburn]

I respect Roger and I also don't belive building mandolins has to be a science project.
If his mandolins are killer then there's some strong evidence as to his method. I just have never seen or heard one.

[DataNick]

I respect Roger and I also don't belive building mandolins has to be a science project.
If his mandolins are killer then there's some strong evidence as to his method. I just have never seen or heard one.

Hey Jim!

My "roast" comment wasn't aimed at you partner! Have appreciated your insight for quite some time on numerous threads...FWIW Roger's F5 to me sounds like a cross between the best of a Gibson F5 and a Gil...

[Marc Berman]

Frank Solivan plays a mandolin he made at one of Roger's camps.

[Mark Gunter]

I don't really think this will turn into a roast Roger thread, only a couple of truly disparaging or dismissive comments have been made and no one as yet has gotten ugly. I'm interested in studying Roger's book for building mandolins and also interested in the science of sound. I don't think there's any problem with critical discussion if people can be respectful about it.

[DataNick]

I don't really think this will turn into a roast Roger thread, only a couple of truly disparaging or dismissive comments have been made and no one as yet has gotten ugly. I'm interested in studying Roger's book for building mandolins and also interested in the science of sound. I don't think there's any problem with critical discussion if people can be respectful about it.

We shall see my young Padawan....

I've seen lesser pointed barbs than those in this thread that ended up banished to the cornfield...carry on!

[Dave Cohen]

I respect Roger and I also don't belive building mandolins has to be a science project.
If his mandolins are killer then there's some strong evidence as to his method. I just have never seen or heard one.

I don't approach building mandolin family instruments "as a science project". I do, however, approach the description of mandolin and guitar motions as science. If Siminoff's mandolins are "killer", that supports that he is making his method work for his objective of building mandolins. But it does not make his assertions about the science of mandolins true. For that, you need experiments that are repeatable by someone else following your description, and you also need an interpretation of the results that is consistent with the laws and formalisms of Newton, Hamilton, and LaGrange. Unless, that is, you are planning on overturning classical mechanics and you are prepared to provide the extraordinary evidence to do so.

[Mandoplumb]

Some times we know what works without knowing why it works, and as has been said we have a tendency to make up the "science" to explain our observation. I think of the natives telling the Pilgrims to plant a fish with their crops to feed the gods, what they said to do worked not for the reason they gave.

[fscotte]

Two points:

Roger is in bounds to be criticized for his methods, because he has put himself out there in many ways, books, classes, making money off his methods. There is no reason to tap dance around Roger's ego. He is a big boy who is fully capable of defending himself. No need to step in and defend him. He reads this forum and has defended his methods, right or wrong, many times.

Secondly, he's a wealth of information about musical instruments and design. He's one of the finest resources for luthiery.