Thats actually what I thought. However, the chanting also counts as music. Its pretty much monotone, but it isn't. The monotone drone achieved is not only affective in its own right, it bears a resemblance to Indian music and other styles of Thai music (Nora, from what I can tell, involves droning) The drone itself is also conducive to meditation.
I'm using a very broad definition of music. Africans traditionally consider anything with repeated patterns msuic, and anything without not to be music (i.e. Mozart wasn't much of a musician) I'm defining it is tonal sound production with the purpose to be affective. (Most music is primarily self affective. Really good music is broadly affective.)
In addition, Buddhism is something that involves more than monks, so are there anything that laypeople do that involves music (including the essentially gregorian-like chanting that forms the basis for many Indian musics)
Also, why exactly are Thai monks forbidden from "music"? I would presume that it has to do with seperating oneself from the the outside world in order to focus on yourself? or something like that.... As Thai Buddhists are forbidden to particate in music, that also affects general Thai society in what forms of music and it's attitude toward music, so this is all interesting.
Thanks
P.S. - SE Asian gongs are much more interesting and varies than chinese gongs. Besides, i know from my time in thailand that there are some outstanding gongs used for meditation - nothing like Chinese gongs at all - WAY cooler IMHO

... just something about the raised cup in the middle that produces much more affective overtone sequences. Chinese gongs are more popular in the West mostly because of there resemblance to Turkish gongs/cymbals (pretty much anything you see on a modern drumset is a turkish style cymbal) ... Besides, I'm not studying Tibet or China, I'm studying Thailand. Thailand has a very interesting and very broad musical tradition. Much broader in many respects than Tibet or China, as Thailand is a crossroads for cultural influence, recieving influence from (and influencing) India, Persia, Africa (African marimbas come from SE Asian ranats), China, Indonesia, as well as its direct neighbors.