When I said violins are in their infancy, I meant violins, and violins only. Similar instruments have existed since before the eleventh century. Again, I own one. My Memling fiddle has been mistaken for some odd violin many times by people who don't know any better. I feel that violins and viols do sound different, but that is more a matter of opinion, and of sensitivity to those things. I'm fairly picky when it comes to music, and I don't think that we'll persuade each other one way or the other. They do sound similar when viewed from a larger scale, I suppose.
When I said fairly loud, I meant that my Memling fiddle, if played properly, can get as loud as a modern violin. Due to the gut strings and body shape, it sounds nothing at all like a violin. I actually prefer the sound. I haven't had the same exposure to those instruments as you, but I have had plenty of access to a few very nice violins. Not as nice or old as the Stradivariuses or the like, but relatively old with wonderful tone.
Kind of off topic, but this guy is particularly good. My fidula (I like the Spanish name, for some reason) is tuned an octave lower at the moment, and fretted like some violas da gamba with the frets tied on. My bow is basically a nicely shaped piece of yew strung with a small amount black horse hair held by stopper knots at each end.
When I finished building mine (not the one above), I was pleasantly surprised that it matched the Memling painting exactly, down to the colors of the various components. The materials used are completely accurate, excluding the sitka spruce back. (It was such a nice piece of wood that I just had to use it.)
TKP: Feel free to skip over these. Right now, we need multiple styles and types of music, so you can do whatever you are most interested in doing at the moment.