This is modeled on the body and structure of a Stradivarius violin, but I’m not trying to replicate the exact model just yet.
I started this project this morning for fun and it went pretty well, probably about 8 hours of work here.
I’m asking for critique on mats, shading and other details because I know it’s a long way from perfect. 
looking good! Perhaps a touch too glossy and the strings all look the same thickness. But that’s just me being super critical. Great work so far!
looks good, just some minor crits: too glossy. tuning pegs stick out too far. tailpiece is at wrong angle. strings should vary in thickness. most importantly, the wood grain should run straight, like spruce wood.
(edit) if you want to get really fancy, add some rosin dust on the body and fingerboard just around the bridge.
i think the glossy is PERFECT, i think the spec is a little high. PLEASE PLEASE PLEASE dont change that glossy. it is good. The spec is just too bright. Turn down the spec and youl be in the clear. Great work, please dont screw it up by ruining a perfectly good finish.
A finish like this is VERY traditional. It is done by hydrating the wood, often Lem oil, tho Stradivarius would not have been as great of a liuther as he was if he had used a generic lem oil concoction and it is still a bit of a secret what he used, Then they do between 2-10 coats of heavy lacquer depending on the intended finish. Lacquer bubles and thickens when it dries so it is then wet sanded, then it is often lacquered with one more coat, then the liuther will wet a cloth in some sort of varnish oil and then coat the cloth in powdered pumis stone. The fine grit of powdered pumis will leave the instrument with a shiny finish and will clean up the surface a little along the way.
YOU HAVE IT RIGHT! make your spec a darker shade of gray, but dont change your roughness.
one more thing: the top surface really needs a bump map that follows the wood grain. this is true for all violins, old and new, as well as acoustic guitars.
he does. look at the instruments top.
ah, so there is.
yeah, its kindof hard to see, but its there. i was impressed when i first noticed it that it was somthing he thought of. Not many people think of stough like that without being told
somthing about the ambient occlusion does feel off. flat surfaces dont seem to have a gradient, idk why. this appears to be cycles and cycles AO kindof sucks in my opinion but it shouldnt be having this much of an issue.
Also maybe try straightening out the grain of wood on the body, usually the grain will go forwards to back or the body will be made from a split peace of wood and will be angled and mirrored. its partially looks, partially structural
thanks, I do need to work on finding a better wood texture.
On my reference the top is one piece, but the underside is two. I’ll disable the AO, I don’t know how much it’s doing for me. 
I liked where you were originally going, but that’s me 
The original texture was great, the modeling is solid. Well done!
it’s looking more realistic, imo, but the grain flow is wrong on the sides. it should go up and down. kind of counter intuitive. also the grain on the top should be more straight, less diagonal.
yeah i gotta say i like the lower spec on the head, but the body now is too dull, somewhere inbetween i think would be good.
again, good work. great model
Well, here’s a bit of a compromise between the two, also render at a bit higher quality. 
Attachments
looking good
I just noticed something I failed to catch. The top should not have the raised border. The top piece of wood should extend slightly out over the sides, but not upwards. usually there is a pin stripe just inside the edge.
This one looks like it has a bit of that edge, but I will work on that. Thanks!
a minor depression perhaps but I think that is mostly the effect of the pin stripe, which seems to be duller than the rest.
hes right, what looks like a border on the z axis is really just from a gouge which is used to give the violin definition and shape but it serves no functional value. It is actually hanging over the sides