I don't know about sound of resistors. I think some believe carbon comp are a large part of vintage toob stuff (ie guitar amps etc). I've not investigated, looked for, nor experienced a difference (except higher noise). I don't think a resistor should have a "sound". If it is a good part with low noise and a respectable ppm tempco it should not matter.
I've been using metal film for a couple of years now and see no need to look further. Each time I need a different value, I just buy a pack of 200 from mouser and add the value to my stash. After a couple of years at this, I'm certainly biased toward metal film! :thumb:
Peace - Out
Irv