in order to do a definitive test of a speaker's ability to reproduce timbre accurately, it is necessary to record an instrument in one's living room and compare the recording to a musician's presentation of the same music.
of course one will need a musician who is willing to particpate in this experiment as well as a way to method for recording, such as an open reel tape deck, a dat, or a cd recorder. hopefully, the quality of the recording is sufficient to make a meaningful comparison.