I think I have now realized that I have a problem with my Mendini 650. I have Prelude strings on her (Vanessa) and also on Jane ($30 Crescent). Jane sounds good, clear, no buzz or ch or zz sounds. Vanessa has an irritating "a" but the d and g are not much better. I cut off the little tube on the a string thinking that might be vibrating, but no change. I have Jargar e string on her that sounds great. I pulled the ProArtes off her because they didn't sound too good and same with the Zyex, but finally I know its the violin in some fashion. Bridge maybe? Its fairly new. I'd rather the fault be in the strings, but I'm past that now. I moved the sound post to no effect on the zz sound. There is also a "chuck" sound when changing directions but I think that is related to the rosin on the bow, maybe not.
I'm about ready to say to heck with it and just play Jane, but even though I say she sounds good, she has a tone like a plastic toy. Think I'll go play drums for a while.
MrYikes, Not sure if it applies but in setting up my mandolin, the luthier I listen to says it is important to be sure that nut and bridge slots are cut just wide enough to contain the string width else you stand the chance of rattles and buzzes. I have read that string slots should just contain the bottom third of the string. Dont know if this will help but I put it out there.
@MrYikes : With all the noises it sounds to me as though you have a demon living inside.
Check to make sure that your chin rest is not touching the tail piece. Also by cutting off the plastic tube on the E string you now take the chance of the E cutting into the bridge.
What "Raywells" says is true too, if the string notches in the nut are to deep, it could cause the strings to touch the finger board causing a zz...