Hacham –
i said that there is no distinction between the three weeks and the rest of the year. I worded it like this deliberately. Rav Moshe supports this.
If ywn plays music the rest of the year, this means that they for whatever reason do not take on the chumrah of Rav Moshe not to play music the whole year. Thus, it is possible to understand why ywn would continue to play music during the three weeks. Because there is no special issur on music during the three weeks. (again, this might only apply to sefirah. see the tshuvah to be sure)
(btw Hacham, why did you choose a name that is so easily confused with another user. Or were you first?)