Marty Kasprzyk

If it is ok to get a true sole surface on a metal plane using a scraper why is it not ok to get true plate edges on wood billets by using a scraper like is often done on base bars with chalk?

Were your joints planed by hand or did you use a jointer?

Do you really think Peter would notice his chainsaw getting a tiny bit duller?

Thank you Anders for posting these articles for us. These were a good jog for my memory and after seeing your modal analysis photos I was reminded how much the the free edges of the f holes move at various frequencies. It follows that these intense movements in the f-hole island area produces quite a bit of sound compared to other areas that don't move much such as the violin's entire plate edges that are glued into a clamped condition seen in your photos. One of your papers "Looking for pathways..."2006 shows you found the f hole length has an beneficial influence on Dunnwald's 'clarity' DE-F band level measurements (1640 to 4200hz-4200 to 6879hz). I suspect that long f holes which are widely spaced would decrease the various island modes frequencies which might be helpful. Back in 2010 Joseph Curtin did an experiment at Oberlin in which slots were made in 1cm increments upward and downward from the f holes of a student violin. (See the attached photo) I recall that the Oberlin listening group was very surprised that the violin sounded better and better as these cuts were made longer and longer. Eventually the changes tapered off with no further improvement. All this suggest that the traditional f-hole length might not be optimum and I was wondering if you or others had any opinions on this.

If it is ok to get a true sole surface on a metal plane using sandpaper sheets on flat plate why is it not ok to get true plate edges on wood billets by using sandpaper on a flat plate?

That might be very true but these two makers also made some not so good violins. I've never heard a good explanation why not all of them were great.

As you thin the plates they get louder and their vibration mode frequencies get lower. The assembled instrument from these plates likewise gets louder and its entire frequency response curve gets lower in frequency. Bissinger's Tran. of Meinel .pdf

I don't like the idea of a tailpiece wagging around wasting energy either so I got rid of them and their tail chords and end pins. The strings are mounted onto an extension of the fingerboard with the same string spacing and arch shape as the bridge such that the string after-lengths are parallel.

I was going to do a methodical study to show how the arch height affects the sound character. I started with a flat top plate and planned to make successively higher arched top plates for the same instrument body. But the flat plate worked well so I skipped all the rest of the experiment. This saved a lot of wood, time, and thinking.

I assume that your "muddy" node lines are wide and diffuse and not narrow and sharp. This might not be due to your plates. I've found that the tea leaves or what ever particles you use has an influence on the node line sharpness--if they have a angular shape or rough texture or static electric effect which limits their movement the node lines aren't very sharp. Rounder smoother particles give better sharpness. You might try something like poppy seeds or the classically used metallic colored plastic "Christmas glitter". But if you are making viola plates I recommend Red Dot or Green Dot shotgun gunpowder. They have smooth surfaces, a highly uniform disk shape of about 1.5 mm diameter and a good contrasting dark grey color.

I agree. Your and Curtin's foot pads and the suggested forward pointing bits are way too narrow to have much of an acoustic effect--but great for durability improvements. So for having an impact on the sound I suggest that the forward bridge foot extensions be much larger--about ten times larger than the 1.55mm increase that Pianootaku has just suggested: around a 20mm wide bridge foot. The reason for this is that it might increase the violin's high frequency output. When a string is bowed the string sticks to the bow hair (that's why we use sticky rosin) as it is pulled transversely away from its static position. Eventually the string is stretched enough that it breaks away and flies backward. The string flies past its neutral static position and is eventually comes to a stop where it is stretched again gets stuck to the bow hair. This one trip string motion cycle produces one bridge foot motion cycle--hence one cycle of the sound being produced. But as the string is first pulled sideways by the bow it stretches the string a little which produces a longitudinal tension increase in the string. When the bow hair looses its grip and the string flies by its neutral position the tension goes to zero. As the the string continues moving it eventually comes to a far away stop in which the string is again a stretched a little. Thus the string produces two longitudinal tension pulses to the bridge for every transversal cycle to the bridge--twice the sound frequency. This effect is well known in guitar acoustics (1) but it is insignificant in violin acoustics because the very narrow violin bridge doesn't transfer the bridge's out of plane vibrations (tipping back and forth and bending from the 2x longitudinal string vibrations) very well to the top plate. Therefore by making the bridge foot much much thicker I would expect better longitudinal string vibration coupling to the violin body--The violin might sound a little brighter with a little more high frequency sound output. Of course if the violin is already too bright or harsh sounding this is in the wrong direction to go. On the other hand if it is too dark or hollow sounding this might help. So you really can't predict if Pianootaku's idea is helpful or not. Nevertheless I predict that even though it might sometimes be helpful it will be not adopted because it doesn't look traditional. 1. "The Physics of Musical Instruments, 2nd edition", Fletcher & Rossing,Springer, 1998, Chapter 9.3 'Force Exerted by String'

The bits pointing forward can be made with separate pieces of wood glued onto the bottom of the bridge feet with their longitudinal grain direction going parallel to the top plate which would be much stronger and less likely to break. "Its difficult to make predictions--especially about the future." But if you try it I predict the violin's sound will either get better, stay the same, or get worse.

It's not clear to me what a "nasal" violin sound is. Duennwald (attached) had claimed about 40 years ago that a high response in the 700-1600Hz range produced a nasal sound quality. However about 10 years ago Mores (attached) did blind listening tests where the sound output of a Strad violin was increased in this range and the listeners didn't describe it as anymore nasal sounding. He claimed from human voice studies that a nasal sound was not from Duenwald's 700-1600Hz band and that it was from a combination of other things. Recently Rozzi et al (attached) did listening tests on four different violins two of which were Strads and listeners rated them differently with regards to "nasal" sound. Rozzi's paper has a good list of references but unfortunately Mores' work wasn't cited. So without knowing how the violin's frequency response curve determines the amount of nasal character it doesn't seem possible to recommend a violin construction and or set-up to achieve it. I suspect different people have a different ideas of what a "nasal" sound is so they recommend different ideas on how to achieve it. Duennwald CAS_.pdf Nasality_in_musical_sounds_it_is_not_a_f-3.pdf A listening experiment comparing the timbre of two Stradivari with other violins: The Journal of the Acoustical Society of America: Vol 151, No 1.pdf

Use shallow arch shapes so you don't have to carve away as much wood.

The nut and the bridge have carefully fitted notches for the strings. Should the tailpiece's fret have similarly cut string notches?