Hi guys,
I have been interested for the past couple months about the -anatomy- of the violin and the evolution of some specific parts. I have been browsing on Brompton's and Tarisio's online catalogs to differentiate some F-Hole designs. Obviously there are some noticeably different ones, but the Amati, Stradivari, Guarneri, Chanot, Maggini, Chanot, and many early XXth century Italian makers have some noticeable differences. I was wondering if there is a -best- f-Hole design, or if their importance in the sound quality in negligible.
John,
An interesting testing concept you have proposed.
I have a different possible influence that the sound hole shape may have: is it possible that the shape (as well as spacing) of the sound hole affects not only the way the sound propagates out of the instrument, but structurally, the shape may strongly influence how the top plate vibrates torsionally from the energy transferred through the bridge?
I can't find the links, but try googling:
"Effect of f-hole shape, area, and position on violin cavity modes below 2kHz" by George Bissinger.
(Catgut Acoustical Soc. Vol2 No2 series II Nov1992)
AND:
"Experiments on the construction and the function of the violin" bu Eric V. Jansson etc.
Same source.
You can bow an open string and with the other hand place a finger over different parts of the hole. For me it's surprising how little difference it makes though some will argue that the exact dimensions of the f-hole cannot be changed. I can't see that myself. I believe that the holes and much of the violin have always had a decorative element.
I have to play a full chromatic scale, quite loudly. The two in-depth studies I mention above are wellworth the trouble of reading.
I understand that some makers and experts have come to some definite conclusions about the effect of lateral f-hole placement on tone - iow, how close to each other or how close to the edges they are has, apparently a definite effect. Unfortunately, I don't remember what the conclusions were. As to shape - typical Strad vs late del Gesu, or total space of the openings made by the f-holes, I believe is much less conclusive. Would any makers care to weigh in?
I am mostly a viola maker. In order to get good basses, I shape my tops in order to create a long and wide plataform, so I do prefer parallel f holes in opposition to slanted f holes.
I do that with violins too.
I'll quote Samuel Zygmuntowicz excellent article called "Interpreting Guarneri" in the Dartington Conference.
These are his comments about the Del Gesú "Kreisler":
"In general, the main purpose of the f-holes is to cut the surface of the top to allow the top to flex and pump. What can one say' about the Kreisler structure? The moderate length, 75.6mm is unremarkable. The upper eyes, however, are rather wide-spaced, 42.7, leaving a broad bridge platform, 74.4 measured at the notches. But there is something else a little about this, the,wide wings, especially the lower wings, give the f-hole hole a lot of what I call "horizontal spread" (from the inside of the upper ff lobe, to the outer edge of the lower lobe, I measured perpendicular to the centre line), and the broad sweep of the lower curve cuts a lot of wood fibres. The horizontal spread on the left ff is 48mm. And the overall spread from extreme lower left circIe to extreme lower right circIe is 131.6.
I would expect this extra horizontal cutting to free up the side to side rocking and pumping of the top. In
this case the top might well need freeing up. The Kreisler's shallow minimal channel, full arch, heavy edge and healthy graduations would all tend to stiffen the top and add mass."
And here Zygmuntowicz's comments about the Kreiler sound?
"What is the Kreisler sound? I hear it as a rather incisive, clear, and articulate sound, with many overtones and a clear focused projection, not as dark as many later Guarneris.
This seems consistent with its relatively stiff arch, channel and edge. The moderate length of the ffs also fits in this picture."
And about Del Gesù "Pannete":
"Now lets look at the Panette from a structural view. The ffs are longer (78mm long), but closer set and with less spread, and with tighter end curves. While the ffs are set at more of an angle, which-would tend to increase the horizontal spread, the horizontal spread is still less than on the Kreisler (44.5mm).The upper holes are set narrower - (39,5mm), as well as the bridge platform (72.4mm), and the overall spread of the overall holes (127.3mm). The channel is deep with a wide scoop. Altogether, it presents a less massive and more flexible structure."
And his comments about the Pannete's sound:
"The Panette has a very dark, warm sound, quite rich if almost a bit hollow. Of course, there are many other factors, such as perhaps the slab-cut back (being softer) and thinner top, which all have effects on structure and sound.
I wish it had a little more edge. If you're not used to playing it, it's a little cushiony.
Describing sound is subjective, and linking sound to specific structural details is quite speculative. Still, attempting to understand these connections is vital."
And here a bit more:
"The 'hourglass' Guarneri shape seems less braced, more flexible and able to twist. Lengthening the f holes cuts more top surface, freeing the top verticalIy. Placing the upper lobes of the f-holes closer might also encourage the twisting and pumping of the top from side to side. Because of this flexibility, the graduation might be a bit thicker, especially in the bouts and on the edges and maybe on the centre of the back as well. "
An important aspect of ports that is rarely considered is the texture and exact shape of the profile of the port. In a loudspeaker, we would generally avoid sharp edges and would polish the port. This may seem trivial, but the model of a piston of air moving in and out is too simple. When the pressure rises inside and air starts to push out of the box (it only has to push out a little bit), it moves at a higher velocity at the edges. I am unclear on the boundary layer system at those edges, but smoothing the edge and rounding slightly the underside of the port has a slight audible effect. I wonder also whether the distance of the wing point to the curved edge at the ends has an effect.
Interesting subject.
I think Sam Z has the right focus: all of the structure aspects and their influence on the full spectrum. As I see it, the effect of the F-hole shape (within normal bounds) has minimal effects on the A0 air mode, and the A0 is just one small aspect of the violin tone.
I have found that a tiny bit of blu-tack on the upper wing of the right f-hole has interesting effects on tone. So has the wing some cantilever property? Earlier holes were C-shaped or flame-shaped, and while the precise shape may not have a significant effect on A0, but it must have some effects on top plate resonances, including the elusive ones above, say, 1kHz.
VIOLA ff-holes
I posted this at Maestronet nearly 17 years ago ( http://www.maestronet.com/forum/index.php?/topic/296747-million-dollar-viola-sound/ ). It describes a method for enriching the lower frequency response of viola by modifying the ff-holes. I still have the original mod on my viola.
I should add tha I ahve tried thesemods on violin and cello ff-holes and they do not improve those instruments.
Andy
By coincidence, in this month's STRAD magazine there is an article on this subject by Stewart Pollens.
Though fairly short, it's not easy to summarize. But it seems to me that a central point of his is that the basic violin f-hole design, though subject to individual differences, came about NOT "from any accumulation of accidental errors, but governed by rigid proportional 'rules' established in Cremona in the early 16th century."
I have two 15-3/4" violas: a narrow-bodied, Strad-shaped JTL, and a 2-cornered viola by Bernard Sabatier, inspired by a Da Salo "Lyra-Viola", which has wide upper and lower bouts, and almost no waist. Its internal volume is considerable, but instead of using this to lower the "A0", Tertis-style, its long f-holes bring the resonance back up to Bb, just like the JTL, but with good "spread" and considerably more power. This, plus the wide waist, gives a broad resonance across all 4 strings.
The wings are very important, and highlighted in a goodly number of somewhat sub-rosa works. Cognizant folks comment on the straighter section of top arching allowing the upper wings to hinge more easily. I suppose the wings can both radiate and act as an energy absorbing element. I work on them systematically during construction and in final assembled tweaking, but cannot claim to have more than a method that works which I don't understand the theoretical underpinnings of.
Andrew, your F-hole tuning is similar to speaker bass-port tuning.
Partly covering an f-hole will lower the air resonance as much as "tubing", but the resonance will be less strong, and have a narrower frequency spread.
Wanting to raise the frequency could be interesting!
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March 29, 2015 at 12:05 AM · Great stuff. And I agree about the 3 vowels.