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alt_2ooning
Feb-06-2008, 10:30am
My understanding is that the prized signed Lloyd Loar mandolins were constructed with a component known as the Verzi ….huh? …what’s that under there? …. my web search led me to discover (don’t know how factual) # that Mike Kemmitzer (Nugget Mandolins ) also builds his mandos with a verzi …….also .I stumbled across a photo documentation of a Lynn Dudenbostel’s #F5 for Chris Thile ….hence another newbie question to follow after viewing the link below …..

http://www.thefishnet.com/makemandolin/page5.htm

What enhanced tonal characteristics does the Verzi produce/emit???……. that is my question……. and I fail to understand why Roger Siminoff has not included the verzi in his manual simply because at the onset of his manual he makes reference that the plans contained in his book are based on the original Loar’s…….. I’m somewhat disillusioned by Roger’s neglect to address the verzi….not to mention being duped.

A close look at Lynn’s work and some searching of Loar’s plans reveal the location of the two inverted #landing pads (feet)to be pinpointed to coincide with the sharp inner point of the f-hole (lateral axis)…….which is theoretically #directly under the bearing points of the bridge…….. could the positioning be related to a static middle node of the fundamental if the top is acting as the fundamental and hence influencing partials surrounding the fundamental #to resonate more readily http://www.mandolincafe.net/iB_html/non-cgi/emoticons/rock.gif…. I don’t pretend to be a physicist ….I have no clue other than applying some of what I feel is #primitive physics 101 logic in my understanding of fundamentals and partials.

Also the C shaped holes are akin ( I believe/think) to the top F-hole…… #my guess here is that the removal of the wood alters tone ……deepens the tone of the partials as more wood is removed.

Loar’s plans indicate the verzi to be centered on the longitudinal axis …… it appears as though Lynn’s is offset towards the bass bar…….. my hope here is that I am not stepping on any toes in the sense of pushing to know the secrets of what produces optimum tone… …I understand those are personal and attained through years of trial and error ….nor would I expect them to be handed out …however #my quest is to attain an understanding of the engineering genius of Lloyd and try to employ some of his principles as made public through his plans.

Like I said in one of my prior posts the deeper I get into this mando build project the nuttier my questions appear….. they are nevertheless sincere and genuine.

Mike
************************************************** *********
...the thousand mile journey begins with (in my case) baby steps
http://www.mandolincafe.net/iB_html/non-cgi/emoticons/biggrin.gif

sunburst
Feb-06-2008, 10:46am
virzi thread (http://www.mandolincafe.net/cgi-bin/ikonboard.cgi?act=ST;f=7;t=36450;hl=virzi)

another virzi thread (http://www.mandolincafe.net/cgi-bin/ikonboard.cgi?act=ST;f=7;t=31238;hl=virzi)

and one more (http://www.mandolincafe.net/cgi-bin/ikonboard.cgi?act=ST;f=7;t=21440;hl=virzi)

Have fun! http://www.mandolincafe.net/iB_html/non-cgi/emoticons/biggrin.gif

alt_2ooning
Feb-06-2008, 10:55am
Thanks John ......along with the late Lloyd you're another genius #http://www.mandolincafe.net/iB_html/non-cgi/emoticons/rock.gif .....once I get this theory behind me I'll trudge ahead boldly ....... in the meantime this Northern boy is still takin' baby steps in finding his way.

Mike

Antlurz
Feb-07-2008, 3:37am
I've often wondered how he arrived at the size of it?? Seems like a bigger disk might be more definitive..

Stephanie Reiser
Feb-07-2008, 3:09pm
Chris has since had the Virzi removed.

MikeEdgerton
Feb-07-2008, 3:18pm
Actually there are several builders that offer their version of the Virzi. Jamie Wiens has his "Wienzi" among others.

JEStanek
Feb-07-2008, 3:22pm
Gail Hester too. I'm likely going to have Brian Dean do something like a Virzi in mine...
I'm a Virzi Fan.

Jamie

Bernie Daniel
Feb-07-2008, 3:37pm
alt_2ooning: What enhanced tonal characteristics does the Verzi produce/emit???……. that is my question……. and I fail to understand why Roger Siminoff has not included the verzi in his manual simply because at the onset of his manual he makes reference that the plans contained in his book are based on the original Loar’s…….. I’m somewhat disillusioned by Roger’s neglect to address the verzi….not to mention being duped.


I have no idea why you feel "duped". All you have to do is email or call Roger he is one of the easist persons to talk to I know. He answers the phone himself 9 times out of 10. In addition he sells ready to install Virzi's -- they are listed on his site for $30. http://www.mandolincafe.net/iB_html/non-cgi/emoticons/rock.gif

Hans
Feb-07-2008, 4:53pm
Just about any builder will stick one of those gizmos in...it's taking it out that will cost ya! #http://www.mandolincafe.net/iB_html/non-cgi/emoticons/smile.gif
BTB, don't know what genius Loar had with the Virzi...didn't one of the brothers have sort of a close relation to Lloyd?

evanreilly
Feb-07-2008, 5:00pm
Waaaayyyy back the rumor was that Lloyd received a kick-back from the Virzi Brothers for each Tone Enhancer installed in a Gibson instrument. Check Snopes.com for this one!

MikeEdgerton
Feb-07-2008, 5:38pm
I was looking for a piece on Roger Siminoff's web page where he addressed this rumor but I can't seem to find it. I did find this (http://www.siminoff.net/pages/virzi.background-2.html) page on the Virzi for anyone looking to find out more about the little disk.

TimPiazza
Feb-07-2008, 6:17pm
I know that a lot of people don't care for the sound of a mandolin with a Virzi installed inside. But that's generally because it makes the sound quality of the instruments less suitable for bluegrass. The only Virzi'ed mandolin that I've spent some time with was Peter Mix's Rigel R-100, and I was absolutely blown away by how beautifully complex the tone was.

Tim

JeffD
Feb-07-2008, 8:41pm
I know that a lot of people don't care for the sound of a mandolin with a Virzi installed inside. But that's generally because it makes the sound quality of the instruments less suitable for bluegrass.
The Siminoff article mentions this - that BGers look for bark, not something the Virzi enhances.

I have never played an instrument with a Virzi, but I would like to. Someone once described it to me as making the (F style) mandolin sound more like a bowlback. Hmmm.

Paul Hostetter
Feb-07-2008, 10:10pm
Virzis ended up in lots of mandolins that had nothing to do with Loar, including rank-and-file A-nothing models with oval holes, not to mention guitars, violins, and other things. I've played quite a few instruments with Virzis, and I don't think they did much of anything except excite the curiosity of some people, most of whom have never seen one or played an instrument with one in it, and certainly never observed the before and after. If an instrument was a good one, it was obvious, even with the weird thingie inside. People have taken them out in hopes of bringing a less-than-thrilling instrument to a better state, but not many people with actual direct experience have felt it really accomplished that. I personally buy the concept (it should do something!), but find the tangible evidence underwhelming.

If you read the links John presented above, you'll see that Frank Ford chimed in on one of them, saying, "In the 1970s, I had occasion to be present at two "Virzi-ectomies." Both were removed from decidedly weaker Loar F-5s, and in both instances, the resulting instruments were decidedly weaker Loar F-5s. The conclusion at the time was that removing the Virzi did not harm the instrument, but if doing so improved the sound, the removal didn't help enough to even justify the work of taking it out. . ."

Can you say "Emperor's New Clothes?" http://www.mandolincafe.net/iB_html/non-cgi/emoticons/wink.gif

Paul Hostetter
Feb-07-2008, 10:13pm
Waaaayyyy back the rumor was that Lloyd received a kick-back from the Virzi Brothers for each Tone Enhancer installed in a Gibson instrument. Check Snopes.com for this one!

I did. There's absolutely nothing there.

danb
Feb-08-2008, 4:38am
I've played quite a few instruments with Virzis, and I don't think they did much of anything except excite the curiosity of some people, most of whom have never seen one or played an instrument with one in it, and certainly never observed the before and after. If an instrument was a good one, it was obvious, even with the weird thingie inside.
I'm wearing the cafe's resident virzi apologist hat, so here are yet more updated observations.

My Wiens does indeed have one, a "wienzi tone bemuser", to be precise.

My playing style has evolved a bit since I first tried one of these gizmos, back when I had that wonderful Loar loan back in the early days of the archive. I used to primarily use a .72 clayton pick. Now what one of those picks will do, you'll notice, is emphasize a fair amount more treble and attack than you'll hear with a thicker one.. once you get into the 1mm wegens and up you start to have more traditional bluegrass tone.

So two observations- I noticed firstly that the thinner picks + virzi seem to result in more of a difference than thicker ones + virzi. They seem to do something in the high register, basically. The tone I like to hear has been evolving in the direction of the bluegrass note, but not quite all the way.. so now I'm driving a .94 clayton ultem on the Wiens, so I still have some of the treble but it's not quite all gone yet.

The second observation is that they work like a "monitor". My friend Craig was visiting with his brand-new Wiens over Christmas, and we did the blindfold tests etc. These two were very similar, built with similar woods, nearly the same time, same finish, etc.

The "listener" could not tell them apart on pure acoustics, but we both noticed that mine (virzi) had the "out front" sound in the player's position, wheras what you heard playing the non-virzi one would be different based on position. I find with this Wiens, I'm no longer always heading for the echoey room or french doors to use as a sound mirror because I don't need to.

I had a virzi a4 snakehead for a while too. In that oval-holed mando, it seemed to really add an awful lot of sustain and what I'd call "shimmer". I've never heard another oval hole mando that sounded like that, having had quite a few pass through in my horse-trading phase. I reckon that effect must be mostly due to the virzi.

A virzi in an oval hole mandolin (specifically a Gibson lateral braced A or F) seems to sound "ethereal" or even echoey.

So anyway, I think that a lot of the dramatic differences I heard at first were due in part to my thinner picks- which I think explains why my experience of them has been so dramatically different.

The "monitor" effect is quite nice though. Mine doesn't appear to have had a harmful effect on volume, I can peel paint with this mando when I lean into the pick.

Craig's (non-virzi) mando sounds almost exactly identical, though it's noteworthy that it wasn't louder or "sharper" or "edgier", all stuff I used to assume you'd see if you had a close pair of with/without to compare.

The only real difference we could notice was if you were playing it, you'd hear more of that "out front" sound from the virzi one.

Bernie Daniel
Feb-08-2008, 5:28am
Regarding the merits of the Virzi sound enhancer

I think one place a person can go to at least be able to compare what the device does to the a mandolin sound is Tony Williamson's "The Sound of the American Mandolin". #

In this amazing project Tony plays a number of early (bowlback L&H, Vega & Gibson) and later (Gibson and others) mandolins, mandolas and mandocellos.

But to this issue he plays back to back, the same tune, on a 1923 Loar (without a V) and a 1924 Loar (with a V) and two 1920's F4's one with and one without the Virzi.

Listen and judge for yourself.

This project is available on VHS and maybe on DVD now?

JEStanek
Feb-08-2008, 7:23am
Thanks Bernie,

For those interested, the "Sound of the American Mandolin" is for sale on Tony's site (http://www.mandolincentral.com/cgi-bin/mandolincentral/store01/perlshop.cgi) but only in VHS format.

Additionally, in the Vintage section DanB participated in this thread and posted sound clips (http://www.mandolincafe.net/cgi-bin/ikonboard.cgi?act=ST;f=27;t=32751;st=0)of mandos with and without Virzis. I can hear a difference.

Jamie

markishandsome
Feb-08-2008, 9:25am
Anyone know what gauge picks were popular in the 20s?

danb
Feb-08-2008, 9:29am
Yes, roughly same as today. Stuff from a .70 on up, more towards the thinner side than we tend to use on average. Gibson sold picks, they are analagous to stuff available now

Paul Hostetter
Feb-08-2008, 12:54pm
Dan, your take on the quality of that effect makes complete sense to me. Not unlike the internal resonator in Selmer guitars, another gizmo I'm familiar with from hands-on experience. They were rather ill-starred, however, because they tended to come loose and rattle, and people yanked them for that reason. Two of the finest Selmers I've ever played, a gut-strung one and a steel-strung one had them, BUT:


...he plays back to back, the same tune, on a 1923 Loar (without a V) and a 1924 Loar (with a V) and two 1920's F4's one with and one without the Virzi. Listen and judge for yourself.
This is the "logic" that to is NOT logic, or in any way compelling. One could play two vintage mandolins both which either did or didn't have Virzis and they could still sound that different. Perhaps comparing 100 of each might mean something. Tiny samplings and anecdotal citings just don't mean much, especially when you;re asked to listen to a recording.

Again, I'm not saying they have no effect - how could they not? - but if they have any, it's not what most people imagine it to be. It's much more nuanced, as Dan says.

Bernie Daniel
Feb-08-2008, 1:58pm
Paul Hostetter: This is the "logic" that to is NOT logic, or in any way compelling. One could play two vintage mandolins both which either did or didn't have Virzis and they could still sound that different. Perhaps comparing 100 of each might mean something. Tiny samplings and anecdotal citings just don't mean much, especially when you;re asked to listen to a recording.

Couple of points -- of course you are correct -- you can't do statistical analysis on two mandolins. The better mandolin might have the Virzi -- so flip a coin.

However, the standard you suggested -- listening to 100 examples of each -- wherein the Virzi is the only variable -- is of course, not likely to ever happen. For example, are there 100 Loars with a Virzi left in the world? #I doubt it.

So it reduces to a philosophical issue, or a matter of opinion, or a question of faith. #Believers believe --

However, in my personal opinion (and I have played the tape many times) both of the mandolins with the Virzi's played by Tony on that occasion sounded more "complex" with more sustain than the two without.

For what it is worth.

JeffD
Feb-08-2008, 2:07pm
So I don't hear anyone seeing enough advantage to have a virzi installed in a previously virzi-less mandolin.

evanreilly
Feb-08-2008, 2:29pm
Then there is the interesting idea/fact that Bobby Osborne supposedly put the Virzi back in his Loar. Fact or fiction?

danb
Feb-08-2008, 2:43pm
Again, I'm not saying they have no effect - how could they not? - but if they have any, it's not what most people imagine it to be. It's much more nuanced, as Dan says.
My previous virzi comments here on the cafe have been a lot more extreme in favor of, but I've now had the experience of hearing two from a really good builder on top of his game that sounded VERY close to identical.. one with and one without. It was such a similar sound that the we (the owners!) couldn't tell them apart with eyes closed and a buddy with a very similar style playing them to us.

We literally just covered our eyes and picked them up at random, our guesses were close to 50/50 right/wrong

Dave Cohen
Feb-08-2008, 2:59pm
I did an experiment in early 2005 in which I put different bracing patterns in a single mandolin with a removable back, and did holographic interferometry and took sound spectra for each pattern. The back was held on with small screws driven into a solid (i.e., not kerfed) lining. The mandolin started with conventional tone bars, then I installed a Virzi thingy built from the GAL drawing and specs. I also subsequently installed an X-brace, and my own wacky braces, but that is not important here. The whole point of that exercise was to eliminate variations in the mandolin's materials, construction, graduations, etc., from consideration, and obsserve differences which were due solely to the particular bracing pattern. Having done that, the obsserved differences between tone bars and tone bars plus Virzi thingy were small indeed.

To begin with, I couldn't tell any difference in the sound between tone bars and tone bars plus Virzi thingy. That in itself doesn't mean there weren't any differences. Had, say, Beimborn or Tony Williamson been there, they may well have been able to discern differences. It wouldn't have been easy, though, as the observations were 24 hrs apart. But they weren't there at the time. Maybe when I get a grant.

Differences in sound spectra and characteristic times (sustains) were insignificant. Modal analysis (holography) showed some small differences. The main body mode was pretty much unaltered. Next mode up in frequency is the sideways rocking motion. The Virzy thingy did lower the frequency of that one noticeably; could have been predicted with hindsight. Not sure what that means, as that mode does not result in strong sound radiation. But the mandolin generally likes that mode, so it does have some impact on the character of sound.

The presence of the Virzi thingy didn't alter either the shapes or frequencies of the first two air modes (Helmholtz resonance and longitudinal sloshing), but it did raise the frequency of the third air mode (sideways sloshing) from around 1.1 kHz to about 1.3 kHz. That mode is not a strong radiator, but it might account for the "hum" or whistle that some players associate with the Virzi thingy. At any rate, it certainly doesn't do what Loar thought it did. But then, I addressed that in one of the threads linked above.

danb
Feb-08-2008, 3:38pm
Dave- the main difference I could tell between very similar mandos (one with and one without) is that the virzi would affect the "out front" tone vs "player perspective" tone, on the virzi you didn't have to reflect the sound off a window or similar to get "The good stuff". virzi-less ones seem to have more of a difference in tone/directional aspect

sunburst
Feb-08-2008, 3:48pm
...could have been predicted with hindsight.
Now there's a technique I'd like to get a handle on, Dave. http://www.mandolincafe.net/iB_html/non-cgi/emoticons/biggrin.gif

Bernie Daniel
Feb-09-2008, 7:33am
Dave Cohen: ....predicted with hindsight.

That is how I have made all of my prognostications for years now.

f5loar
Feb-10-2008, 6:23pm
Bobby Osborne indeed did remove it from his Dec. 1 '24 Loar because he couldn't hear it. He put it back in because Sonny couldn't hear it! Go figure.
Virzi Loars remain a myth but I can tell you my Virzi Fern Loar is one whooper of a Loar and I would never consider taking it out. I do agree with the Osbornes in that the listeners can hear it better then the actual picker.

alt_2ooning
Feb-10-2008, 10:08pm
Bernie (Mando 144 ) …>>>I have no idea why you feel "duped". All you have to do is email or call Roger he is one of the easist persons to talk to I know. He answers the phone himself 9 times out of 10. In addition he sells ready to install Virzi's -- they are listed on his site for $30. <<<

Wrong choice of words on my part Bernie….. I was trying to express the disappointment that he never included the Verzi in his manual ……. I was looking for direction and technical commentary on design from Roger in print form….anyway I’m taking my #foot out of my mouth ;-)…apologies Rog…any future questions relating to him I will direct there.
.

Hans >>>BTB, don't know what genius Loar had with the Virzi...didn't one of the brothers have sort of a close relation to Lloyd? <<<
Hans ….thanks for the correction ……it wasn’t until I had gone through all the threads that John posted #that I discovered the origin of the Verzi….. it was brothers Verzi and not Loar.

I’m still willing to go through the #experience (no hurry at this time) #of installing one #to determine for myself if a Verzi truly enhances tone ( additional partials) or if it simply has no effect….. #and if # warrants the additional work and Engleman/Adirondack/Sitka. ….I’m partial to gaining additional partials (pun intended) regardless of stringed instrument.

I pulled this off Rog’s site of #Loar’s experience with the Verzi ( hopefully I haven’t breached web protocol #by copy /paste) "Testing the tone of my viola, I find that: previously those notes having the most pleasing tone color of any possible to the instrument under the most favorable conditions had but twelve [audible] partials or overtones. I am now able to identify fifteen and find indications of three more which are apparently too high in pitch to register definitely [to the human]."

My next question is Directed to Dave Cohen

>>>>To begin with, I couldn't tell any difference in the sound between tone bars and tone bars plus Virzi thingy. That in itself doesn't mean there weren't any differences. Had, say, Beimborn or Tony Williamson been there, they may well have been able to discern differences. It wouldn't have been easy, though, as the observations were 24 hrs apart. But they weren't there at the time. Maybe when I get a grant.

Differences in sound spectra and characteristic times (sustains) were insignificant. Modal analysis (holography) showed some small differences. The main body mode was pretty much unaltered. Next mode up in frequency is the sideways rocking motion. The Virzy thingy did lower the frequency of that one noticeably; could have been predicted with hindsight. Not sure what that means, as that mode does not result in strong sound radiation. But the mandolin generally likes that mode, so it does have some impact on the character of sound. <<<<

Dave , in regards to the above content of your post and pardon my lack of knowledge regarding the analysis you presented ….however could you please comment on the preceding paragraph to yours pertaining to #what Loar himself was quoted regarding partials…… was there any evidence of substantiating or disproving #Loar’s belief/theory that in fact additional partials were revealed with the installation of the Virzi.


I’m open minded to the concept of the additional partials that the Verzi could produce ……..having worked/rebuilt grand pianos I would find it most interesting to actually perceive/see evidence of partials (with the dampers lifted then certain strings (notes) #throughout the keybed vibrating in sympathetic frequency in harmony with #the fundamental and it’s partials. ….key factor was a pure well tempered scale ……. #minute errors in tempering the scale #(+ or - a few cents) removed the visual evidence of partials as the string frequencies were out of sync…..hence color tone became somewhat single faceted rather than multi timbres of the fundamental ( in a well/absolute tempered scale) with it’s accompanying partials…….another point is the strike point of the hammer against the string …. #critical distance # striking the static 7th partial node point at 1/7 of the string length was critical …the key bed can be adjusted for the hammers to make contact at the critical node …… striking the string off the node would influence overall tone and subdue partials I found ….I know this is piano tech stuff however #I believe there might be a parallel in this thinking as applied to mando …i.e. nodal strike points and absolute true temperament .

The placement of the feet under the lateral axis (bridge bearing point) suggests to me that the Verzi is in itself a tuned component ( the f holes in the Verzi I feel must be related to tuning the Verzi which in turn would affect the overall tone of the top) …….therefore #the Verzi would appear as a #component vibrating in sympathy with the top ……some of the data collected from within the some of the links in John’s thread suggest the weight of Verzi to be 4% of the top ……I believe #a 4% weight increase to the top will raise the pitch of a tap toned tone #top with tone bars in place 4% of the number of cents in a chromatics scale…… hence 4% of the number of cents within a chromatis scale amounts to approximately 50 ….therefore a half tone raised pitch would be the result with one installed on the top ……. therefore thickness graduation of the top prior to installing a Verzi must be considered to attain a top tap tone of #a semi tone lower than the back…….therefore #prior to installing the Verzi would be a tap tone of the top #EQUAL to the back rather than a half tone lower at this point.

I’ve saved a 75 thou wafer from my Engleman top block and hope to employ what I have been able to theoretically deduce to discover whether this whole Verzi exercise is fact or folly ……. we each have an individual instrumental tone (mental visualization) #we strive to create/duplicate #….the appeal of additional partials interests me more than amplitude and projection .

I’d be remiss if I never thanked all the contributors to this post and the contributors to the #post/threads #contained in the series of links John posted. …thank you folks ….much appreciated.

I did ‘say’ at the onset of this thread that my questions and thoughts appear nuttier as I sink deeper into this discussion ……. as I stated before they are genuine no matter how far off the wall they appear.




http://www.mandolincafe.net/iB_html/non-cgi/emoticons/coffee.gif time for one of these and some #http://www.mandolincafe.net/iB_html/non-cgi/emoticons/rock.gif

Mike ..... alt_2ooning ...or maybe just for today loony tuning ...... #http://www.mandolincafe.net/iB_html/non-cgi/emoticons/biggrin.gif

Dave Cohen
Feb-10-2008, 11:30pm
Loar presented no experimental evidence of additional partials in any of the writings such as his letter to the Virzi brothers. Nor were there any peer-reviewed publications. If he actually did any experimental work, it was probably proprietary, owned by Gibson, and not for public consumption. I saw no spectral evidence for additional "partials" with the Virzi thingy installed in my mandolin. His terminology would have been better if he had referred to "greater amplitude of the higher [/I]harmonics[I]", but I saw no evidence of that either. There are so many other variables involved in harmonic amplitudes that there is just too much left out of Loar's story.

Since plates, boxes, enclosed air masses, etc., are not even close to harmonic, Loar had to be referring to strings. If you pluck a string near the middle, you will get relatively greater amplitudes of lower harmonics and relatively smaller amplitudes of higher harmonics. If you pluck the same string close to the bridge, you will get relatively greater amplitudes of the higher harmonics and relatively smaller amplitudes of the lower harmonics. If you pluck a string, say, 1/5 of its' length away from the bridge, every 5th harmonic will initially be weak or absent, but the missing harmonics will gradually grow in amplitude as the overall string amplitude decays. Pluck it 1/8th of its' length from the bridge, and every 8th harmonic will initially be weak or absent, and so on. Loar didn't specify anything about the conditions of his experiments, so we can only speculate about what he did or didn't do. However, nothing that he did should be confused with "theory". Classical analytical mechanics is a theory. Thermodynamics is a theory, An assertion that a string has more higher harmonics in the presence of a Virzi thingy is neither broad enough in scope, nor was it sufficiently experimentally tested to qualify as theory. Additionally, the number of harmonics of a struck or plucked string is limited far more by its' own stiffness than by a mass hung inside the instrument body. It is far more likely that motion of the Virzi thingy would steal energy from higher body modes, in turn stealing energy from higher string harmonics, than that it would somehow add harmonics. In fact, you could make a stronger case for it warming up the sound by inhibiting some of the more strident high frequency motions

The stuff in Loar's 1922 letter to the Virzi Bros. about the Virzi thingy inhibiting wolf notes in violas by allowing the air column to vibrate at many different frequencies was way off. Never mind that it showed a complete lack of knowledge of normal modes of motion. The origin of wolf notes in bowed stringed instruments had been correctly explained in two papers by C.V. Raman in 1916 and 1918, and had nothing to do with frequencies of air modes. I alluded to that in my post above, and iirc gave the references in one of the earlier threads to which John Hamlett provided a link to above. If you are interested in the actual normal modes of mandolin bodies and enclosed air, you will find references and abstracts to the Cohen & Rossing papers in the Acoustics section of my website, http://www.Cohenmando.com.

The Virzi thingy as built from the GAl drawings and specs has a mass of about 15 g, making it about 10% to 15% of the mass of a top plate. Hanging a mass like that from a plate will not raise its' modal frequencies, but rather will lower them by about the square root of 1.10 to 1.15.

alt_2ooning
Feb-12-2008, 2:03pm
Thanks ever so much Dave for addressing #my question to you and for clarifying erroneous deductions/calculations #I was making from interpreting the threads that were listed ……. you have made it very plain then that the Verzi is a ‘thingy’ from an acoustical standpoint that DOES NOT increase partials #as Loar in his quote would have one believe. #

Dave your invaluable #input regarding this issue has relieved the unnecessary mental strain in my first attempt to get everything ‘just right’ ….after the data you presented through your personal experience/testing #therefore #the idea of installing a Verzi now goes to the back burner…..at some time down the road after a few mando builds I might resurrect #the interest to install one if nothing more than for the folly of having conducted an experiment I have been advised that #produces no noticeable partial tonal difference……. for now with the direction both you and John have provided I feel pretty much assured a mando sans Verzi is without any question of doubt the #best route to follow.

The fact that some threads discuss the #removal of the Verzi on the old Loar’s validates #the ineffectiveness of tonal enhancement of the Verzi….which reflects pretty much what you outlined.

Thanks again #for your contribution and accessibility to your time and expertise ….also the link to your web site.

Mike

Mario Proulx
Feb-12-2008, 9:28pm
Ya know, first time I saw a picture of a Virzi, I assumed it was attached to the back, and worked as a sympathetic soundboard of sorts.

Has anyone ever tried that?

Michael Lewis
Feb-13-2008, 1:43am
Mario, that makes as much sense as attaching one to the top. How about a double Virzi? Or how about 2 Virzis , one attached to the top and one attached to the back, and set at a critical distance from each other? ( Let your minds wallow in that!)

http://www.mandolincafe.net/iB_html/non-cgi/emoticons/biggrin.gif http://www.mandolincafe.net/iB_html/non-cgi/emoticons/laugh.gif

MikeEdgerton
Feb-13-2008, 7:33am
Would the plural of Virzi be Virzi? http://www.mandolincafe.net/iB_html/non-cgi/emoticons/smile.gif

Mario Proulx
Feb-13-2008, 9:19am
Virzii?

Michael, the reason I assumed it was attached to the back was that the mass wouldn't be an issue then, yet it would still work as a sympathetic soundboard.

oldwave maker
Feb-13-2008, 9:35am
I prefer to install the virzi on bolo tie hardware, with a couple of tuner buttons at the ends of the braided leather string, like the one Spruce was modelling at wintergrass a few years ago.....

Hans
Feb-13-2008, 9:41am
Virzi'z!
I heard 'ole Lloyd spent most of his time adjusting the CC-holes on the treble side of the Virzi'z to tune the disc. B-flat I heard...

Paul Hostetter
Feb-13-2008, 12:07pm
Peter Zaret is a violin hustler in Ohio who, for a small (ahem) charge, does a bassbar amendment that puts him squarely in the camp with the Virzis and a host of other people who all did the same thing: add a resonating mass to the top of an instrument. (Why would anyone think attaching one to the back would do much of anything more than hanging one around your neck would?)

http://www.lutherie.net/zaret.gif

Here's something to ponder: the general feeling among violin folks, notably those who hang out at the Oberlin workshops, is that Zaret's allegedly patented gizma (plural of gizmo), which on close inspection are famously slapdash with no two alike) actually do help warm up and fatten the sound of the violins. This is from people who have done fairly extensive before-and-after examinations with them. And who were quite loathe to concede they were more than a shuck. Whether they're worth the extraordinary amount of money he charges ($1500 and way up) is a side issue I'm not interested in pursuing, but there is something to the basic concept that amending the mass of the top has an effect (duh) and that maybe it can be beneficial.

I still marvel at how people delight in dumping on and explaining away the Virzis (in mandolins, only) based on vague anecdotes and sciencebabble, yet the people who own them, really play them, have deep experience with them, never seem to diss them. What's up here?

danb
Feb-13-2008, 1:55pm
I still marvel at how people delight in dumping on and explaining away the Virzis (in mandolins, only) based on vague anecdotes and sciencebabble, yet the people who own them, really play them, have deep experience with them, never seem to diss them. What's up here?
Well the summary is they sure seem to do something. I've tried to show folks what I'm hearing with sound clips etc.. and lately I've noticed just how much of a difference it makes with picks, especially if you use heavy ones.. they do less..

Mario Proulx
Feb-13-2008, 3:54pm
Why would anyone think attaching one to the back would do much of anything more than hanging one around your neck would?

Because the back on a good mandolin moves nearly as much, if not more at times, than the top, and attaching it to the back wouldn't hamper or change the top's response. That's why....

Paul Hostetter
Feb-13-2008, 6:20pm
Oh. Well. Do you put the bridges of your mandolins on the back? Most people put them on the front, and use a more resonant top material than what backs are usually made of as well. http://www.mandolincafe.net/iB_html/non-cgi/emoticons/smile.gif

Moreover, the point of the Virzis and the dozens of other similar things is that they are always attached to the tops, I assume for a reason!

This is Matteo Casserino.

http://www.lutherie.net/matteo..sm.jpg

He always told people he made this mandolin himself, even though it still said Gibson on the headstock. In fact all he'd really done was replace the back with a 1/4" piece of fir plywood and painted it a strange color. It sounded superb, not just because of how he played, but because of how it really sounded. Of course, jammed up against his tummy, as most mandolins are, the matter of back resonance is somewhat moot.

I don't dispute that a mandolin's back radiates some sound, but to think a Virzi would do much mounted to it is perhaps stretching things a bit, non? Especially since what it does to tops is so ineffable, even for its biggest fans.

So anyway, when ya gonna make a mandolin with Dueling (removable) Virzis?

Mario Proulx
Feb-13-2008, 7:37pm
Of course, jammed up against his tummy, as most mandolins are, the matter of back resonance is somewhat moot.

Many/most of us play with the mandolin angled slightly so that the back isn't choked off by being completely held against our bellies, or simply use a Toneguard. I guess everyone should throw away their Toneguards now that you've spoken and made us realize we've not been hearing a difference after all. And all those holographs or whatever that Dave Cohen carries with him to demonstrate modes is all BS too, I suppose?

Think for a minute.... or two.

Dave Cohen
Feb-13-2008, 7:42pm
Ironic that Paul used the term "anecdote" and the phrase "sciencebabble". What makes an anecdote an anecdote is that it is an isolated account of something, and thus not repeatable. My experiments were described such that they could be repeated by anyone willing to take the effort and time, which is why the reviewers approved them for publication. The observations about strings were not babble, but rather were properties well known since the time of Bernoulli (ca 1725). Today, anyone with a computer and a copy of Wavesurfer or Audacity software can pluck the strings of their favorite guitar or mandolin and see exactly the results which I described in an earlier post.

What is more important is that in no way did I diss the Virzi thingy. To the contrary, I said that while I did not hear any differences between a mandolin and the same mandolin with a Virzi thingy installed, someone like Beimborn or Tony Williamson may well have been able to hear a difference. Hardly dissing. What I did say is that the Virzi thingy doesn't behave anywhere near the way that Loar described. Needless to say, the experiments which led me to those conclusions are also repeatable.

Dale Ludewig
Feb-13-2008, 7:48pm
Mario,

now you have screwed it all up. Shush!

Mario Proulx
Feb-13-2008, 10:22pm
Okee dokey. I be shushing....

alt_2ooning
Feb-13-2008, 11:07pm
>>>>The Virzi thingy as built from the GAl drawings and specs has a mass of about 15 g, making it about 10% to 15% of the mass of a top plate. Hanging a mass like that from a plate will not raise its' modal frequencies, but rather will lower them by about the square root of 1.10 to 1.15. <<<<

Dave if time and patience permits please address this question/deduction ……..my read #of the above leads me to the following # understanding……. if my target tap tone for the top is D (293.66 CPS ) then from your explanation by adding a Virzi #of 15 grams mass lowers the initial tap tone 4. 88 cents #varying to 4.99 cents in the direction of C# (277,20 CPS)….for all intents and purposes then a 5 cents drop in pitch …….therefore for #a pre Virzi tap toned top #my understanding is then the top to have a tapped-tone frequency of 298.66 ( i.e. 293.66 + 5) ……. I’m keeping all this info for future reference down the road.

Mike

Paul Hostetter
Feb-14-2008, 12:39am
As long as you are trading in measurements you have read somewhere, instead of relying on hands-on experience with the actual instruments, you are utterly lost in space. Unless you plan never to make or play an instrument, why save all this info for future reference down the road? It’s only words and blind faith in those words, not experience.


This is starting to sound like a real academic discussion. http://www.mandolincafe.net/iB_html/non-cgi/emoticons/laugh.gif I'm reminded of departmental meetings especially when limited funding came up.
Indeed. And in a thread where Virzi is spelled Verzi. I think we’re all on thin ice here.


Many/most of us play with the mandolin angled slightly so that
the back isn’t choked off by being completely held against our bellies,
or simply use a Toneguard. I guess everyone should throw away their
Toneguards now that you’ve spoken and made us realize we’ve not been
hearing a difference after all. And all those holographs or whatever
that Dave Cohen carries with him to demonstrate modes is all BS too, I
suppose?

Think for a minute.... or two.

Hmm. That’s a pretty defensive swipe, and I don’t think it was merited. I’m just trying to have a conversation. I have been playing in bands where I or someone else in it was playing a good mandolin for forty-five years. And I have been luthierizing good instruments for as long. Perhaps you believe everyone uses a Toneguard or holds their mandolin “just so” to maximize those back vibrations, but it’s simply not the case. Please don’t refer to the “Royal Us” to try and make me or anyone buy the notion that real mandolin players routinely angle their instruments like that. I try to, personally, but to be quite honest, many/most players just sit there and play their mandolins, like Matteo did. They’re interested in playing music, not in squeezing nuances and details of tone out of every surface in the instrument. Think for a minute...or two, your own self. Sheesh. Can't we just toss ideas back and forth and not get our noses out of joint?

Mario Proulx
Feb-14-2008, 12:55am
Paul, my entire point is that the same thing that makes the back move, would make a Virzi type thing move. You questioned, in a very condescending fashion, why would I think it would do anything when attached to the back, and that's why. Think passive speaker designs. Think passive radiator, perhaps.

You're the one taking swipes without understanding what we're speaking of or questioning...

Paul Hostetter
Feb-14-2008, 1:09am
I wasn't taking swipes at all, and I certainly wasn't being condescending. Sorry if that's how it came across, it wasn't at all my intention. Nonetheless, I really don't believe the back is as important as you evidently do. If a top is a 10, a back is a 1. If a Virzi in a top makes 1% of difference to a keen listener, the it'll be 1/1000% in a back. And if you think the back vibration is that important, by all means put a Virzi in one you already know, and see if it does anything. If it does, and you expect this idea to mean anything to others, make a bunch of them and show them around. Talk is cheap. Experience is far more meaningful.

Hans
Feb-14-2008, 7:35am
Here's something to ponder: the general feeling among violin folks, notably those who hang out at the Oberlin workshops, is that Zaret's allegedly patented gizma (plural of gizmo), which on close inspection are famously slapdash with no two alike) actually do help warm up and fatten the sound of the violins. This is from people who have done fairly extensive before-and-after examinations with them. And who were quite loathe to concede they were more than a shuck.

I still marvel at how people delight in dumping on and explaining away the Virzis (in mandolins, only) based on vague anecdotes and sciencebabble, yet the people who own them, really play them, have deep experience with them, never seem to diss them. What's up here?
Sorry if I seem to be a skeptic about these gizmo's Paul, but they just seem to be such a hype to me. Yes I have one in an instrument, but it doesn't do much for me. Considering all the hype they got (Heifetz, Kreisler, etc), I'm inclined to believe hype is just the same then as now...paid endorsement. I could be wrong, but I seriously doubt that Heifetz' instrument had one put in.
However, here's the more important point. Violins are made to be taken apart. Mandolins are not. If Zaret's gizmo warmed up and fattened the tone on violins that's fine. You can take 'em apart and put 'em back together. I have heard a lot of noise about warming up tone in mandolins by having the Virzi, but (as far as I know) no one has ever said that the tone on their Loar got colder when the dingus was removed.
Now, considering mandolins just don't pop open, if I would want a mandolin with a warmer tone, I would use some other spruce than red (not to mention a different maple), and if I wanted a fatter tone (something my instruments are known for) I would graduate the top thicker. Of course, if someone wants one, I'll put it in.
Not trying to argue, just making my point, it's been my experience that backs make a difference in tone and that they are quite important.
I'll shut up now and that's all I have to say about Virzi's. # http://www.mandolincafe.net/iB_html/non-cgi/emoticons/smile.gif

MikeB
Feb-14-2008, 9:27am
I hope you luthier/scientist/artist/philosopher guys realize how much the rest of us (well...me, anyway) enjoy and benefit from discussions like this. I'm not kidding. Knowing that experts do not agree on such things is informative and validates our own ambivalence or confusion. I am convinced I might or might not notice (or like) the effect of a Virzi. http://www.mandolincafe.net/iB_html/non-cgi/emoticons/wink.gif But, I am also convinced I wouldn't pay to have one removed or installed.

The Emporers DO wear clothes!...but, they wear different ties! http://www.mandolincafe.net/iB_html/non-cgi/emoticons/laugh.gif

Dave Cohen
Feb-14-2008, 10:32am
Paul said:

"As long as you are trading in measurements you have read somewhere, instead of relying on hands-on experience with the actual instruments, you are utterly lost in space. Unless you plan never to make or play an instrument, why save all this info for future reference down the road? It's only words and blind faith in those words, not experience."

Paul has made this assumption/implication before, and I feel the need to set the record straight. I am a luthier first, and a physicist second. I have made about 60 mandolins/mandolin family instruments, a couple handfuls of guitars, and I have done a fair amount of setup and repair locally. Two of my mandolins won 1st and 2nd place in a blind listening test at the 2006 CMSA convention in Louisville. The winners of the 2003 and 2007 CMSA classical mandolin competitions were playing mandolins made by me. I think that qualifies as hands-on experience. I haven't spent time on this board touting my virtues as a builder; I think that should speak for itself. And yes, I play mandolin and guitar as well, though my playing is not worth bragging about. Regarding my words, I have absolutely no faith, let alone blind faith, in the scientific work which I do. Faith is not the way of science. When the body of repeatable data grows large, you can have confidence maybe, but not faith. 'Nuff said on that.

Now to Mike's question:

I usually don't venture into cents, except when tuning and intonating my instruments. Btw, what you called "CPS" is now called "Hertz" (Hz). Most software (e.g., Wavesurfer, Audacity) is calibrated in Hz. What you asked about is a free plate motion.

One difficult aspect of free plate modes is that there's not just one of them, but rather, there are a whole lot of them. The stiffness of the plate along the grain is anywhere from 7 to 20 times greater than the stiffness perpendicular to the grain. There are modes involving bending along the grain, and also modes involving bending across the grain, all occurring at different frequencies. When some of the modes are close together in frequency, they appear to combine, which makes things more confusing. I usually tap my plates into a microphone and record a apectrum which shows me peaks for the modes up to about 2 kHz. Above 2 kHz (sometimes lower), they tend to run together. One thing you will find from free plate modes is that even pieces of wood adjacent to each other in a billet can be quite different from each other. In some cases they can be quite similar, but in other cases they can be dramatically different. There are some people who do a lot with free plate tuning, notably Peter Coombe, who may chime in. He also has some nice articles on his website. I don't try to tune the free plate modes, though, and consensus in previous threads on this topic has been that many luthiers don't bother with it.

Another difficult aspect of free plate modes is that they are nothing like the modes of the assembled instrument. The modes of a free plate are like bending motions of a simply supported bar or beam. "Simply supported" means that the bar is resting on supports at its' nodal locations. When you clamp the plate all around its' edge by gluing it to ribs, the motions are completely different, and they occur at different frequencies. The analogy there would be a bar or beam which has been clamped at both ends. For modes of assembled mandolins, you have to go to the Cohen & Rossing papers. There is more literature on guitar modes. See for example, the articles by Tom Rossing, Graham Caldersmith, and others (and references therein) in "The Big Red Book of American Lutherie", volume one. To end a short story that has been made long, I tap my mandolins into the computer mic at various stages in their construction, including completion. The information is still "for future reference", thouhgh there are some benefits from it. One benefit is that I know exactly what the particular instrument is doing, and noting similarities and differences between it and other instruments. And yes, that too is experience.

http://www.Cohenmando.com

alt_2ooning
Feb-14-2008, 9:03pm
Dave again I appreciate your input #…your patience and explanation #in dealing with the questions I posed is truly appreciated ….I found the link #as you suggested to be of great interest.

http://www.petercoombe.com/jaamim7.html

Mike

dunbarhamlin
Feb-15-2008, 8:11am
I haven't tried a Virzi on the back, but I've used deep (almost full depth,) (almost paper) thinned back braces on my cylinderbacks. I like the sound - lots of overtones, almost like tuner-nut/bridge-tailpiece sympathetics (which it isn't - I've checked). But whether this relates to the brace style or not I don't know as I am yet to complete one with a normally braced back - a straight Vega clone is on the bench now.
Cheers
Steve

AlanN
Feb-15-2008, 8:35am
O, this talk of Virzi, so dire,
Heats up men and animals like fire.
If you're so inclined,
Build a mandolin with one, you'll find
that it's still tough to find a buyer.

It's only wires and wood, fellows...

alt_2ooning
Feb-18-2008, 7:49pm
Mario Proulx Feb. 12 2008, 22:28
Ya know, first time I saw a picture of a Virzi, I assumed it was attached to the back, and worked as a sympathetic soundboard of sorts.

Has anyone ever tried that?



Michael Lewis Feb. 13 2008, 02:43
Mario, that makes as much sense as attaching one to the top. How about a double Virzi? Or how about 2 Virzis , one attached to the top and one attached to the back, and set at a critical distance from each other? ( Let your minds wallow in that!)


Steve #(dunbarhamlin )

Giuseppe Virzi’s patent as entered in the US Patent Office is accessible via the link below
http://www.freepatentsonline.com/1412584.pdf

JEStanek
Feb-18-2008, 7:57pm
If you wish to see the patent, you will need to register with the linked website. It requires only an e-mail address and is free.

Jamie

Bill Snyder
Feb-18-2008, 10:30pm
If you use Google to do a patent search you don't have to register. Here (http://www.google.com/patents?q=virzi&scoring=2)are some results using the Google patent search. Take your pick.

david blair
Feb-20-2008, 7:54am
Something about the sound originating in the center...

I installed a harp pickup recently. It has feet like a virzi, from rosewood, connected to each other with ultra light brass tubing and a pickup. It sounds good in the middle.

For Mr Cohen- Thanks for sharing all of your experiences. It's not all in vain. And I have a suggestion for you regards to the mic method you described. Recent technology related to feedback suppression with phase cancelled dual mics/transducers have found their way into things like better MRI results. Discussions with designers of defibrillators and timing issues of the pulsed charges suggest a method using musical theory of modes, octaves, harmony would be a breakthrough. #Anyway, careful voltage regulation and phase canceling might help you pass that MHZ barrier, and further "tune" the high harmonics.

Here's a conversation piece. The link Mike posted below is a Loar with a spruce back, and an adjustable pickup.

MikeEdgerton
Feb-20-2008, 8:04am
I think this (http://www.usd.edu/smm/ElectricInstruments/LoarInstruments/10811/LoarGuitar.html) is the link David was trying to post.

Dave Cohen
Feb-20-2008, 8:46am
David, the technology is not a barrier to looking at higher modes. Even long-standing fft technology will get us up to 5 kHz or more. If resolution should become a problem at higher frequencies (it hasn't yet), wavelet transforms would extend the frequency range significantly. The higher modes in mandolins and guitars (>1 kHz) just get closer together in frequency until they effectively form a continuum. I have looked at some mandolin modes as high as 2 kHz with holographic interferometry. The amplitudes are small, it takes a lot of current to the coil (i.e., force) to drive them hard enough to image them, the top plate and back plate modes are not well-coordinated with each other, and they are nowhere near in frequency to significantly radiating air modes. Air modes above the third one, at about 1.1 kHz, have very small amplitudes and are almost certainly insignificant in radiating sound. So in plucked stringed instruments, the lower modes are dominant. Btw, we are talking about body motions here which are nowhere near harmonic. The higher body motions are mainly involved in losses. The losses do have an impact on sound and sound quality, but there is really nothing a luthier can do to "tune" them. That, plus focusing on the lower frequency motions, ca <1.5 kHz, is a much more effective use of his/her time.

http://www.Cohenmando.com

siminoff
Mar-17-2008, 12:31am
The Virzi Tone Producer was an accessory in many Gibson instruments including F5s, A4s, F4s, H5s, and L5s. The design was the development of J&J Virzi Brothers and they were issued a US Patent in April of 1922. In the F5, H5, and L5, the Tone Producer was centered between the two longitudinal tone bars, so this forced it off the centerline axis. Regarding Lynn’s mandolins, the off-center positioning wasn’t something Lynn invented – rather the positioning of the Tone Producer in his mandolins is an accurate replicate of what Gibson did. Lynn is very sharp on those details.

The Tone Producer has two forward feet and one rear foot, with the forward feet positioned ˝” behind the cross-wise center axis of the bridge (on the F5). The plates were typically very wide-grained spruce and were .090” thick. I didn’t include the Virzi in The Ultimate Bluegrass Mandolin Construction Manual because I didn’t want to suggest that everyone should install one. However, I do have a drawing of it in our ProSeries F5 Drawings, and as Bernie suggested, we do make them available in our price list, and when requested, we install them in our assembled bodies.

Lloyd’s personal F5 has a Virzi as does his viola. Bear in mind that Loar was into classical music and the tone color the Virzi offered was right for him – he was not looking for the “chop” that bluegrass pickers like. As to the rumor, I do mention in my website that “many (others) believe that Loar’s relationship with Virzi led to his demise at Gibson…” but I also go on to state that I don’t have the facts to support that rumor. I believe Loar's departure had much more to do with Loar and Williams being interested in electric instruments and Gibson management saw the company as an acoustic instrument maker. (And, we know from a student's notebook from one of Loar's classes at Northwestern that he was not enamored with acoustic instruments of the day.) We do know that Loar and Williams left Gibson to start AcoustiLectric. Regardless, the Virzi was cancelled as a Gibson accessory when Loar left, and the Virzi page in Gibson’s 1925 Accessory catalog/price list is stamped “CANCELLED.” I think Dan’s observations on the type of the pick used and the “out front” sound are interesting and valuable.

Interesting thread from all!

Roger Siminoff

BlueMountain
Mar-17-2008, 11:47am
Could any of you tell me:
1. How long are the Virzis used in Loar-era Gibsons?
2. How wide are they?
3. How long are the legs, from plate to the bottom of the feet?

I see from elsewhere that Lynn Dudenbostel made the feet on Thile's mandolin 1/4" thick and the plate 0.075" thick.

Thanks

Dave Cohen
Mar-17-2008, 10:30pm
The Guild of American Luthiers has a 1923 F5 plan which includes a detailed drawing, with dimensions, of the mandolin Virzi thingy. Go to

http://www.luth.org