Tosefta for Arakhin 19:15

The flutes do not push away the Sabbath. Rabbi Yosei son of Rabbi Yehuda says, it does push it away (i.e., the flutes may be played on the Sabbath). [And] one would not play with two flutes [simultaneously] but rather with one flue. They would not conclude [the service] except with a reed [flute] because this concludes [the service] nicely (Arakh. 10a:3). Rabbi Shimon ben Gamaliel says, hydrolim were not used in the Temple because they confuse the voice and ruin the pleasantness. Who are those that play before the altar? They were servants of the priesthood, the words of Rabbi Meir (Arakh. 2:4, Sukkah 51a:1). Rabbi Yehuda says, servants of the Levites. Rabbi Yosei says, [they were] family members of the House of Happegarim [and family members of the] House of Tzipperaya, from [the city of] Emma'un, and they would marry [their daughters] to the priesthood. Rabbi Chananiah ben Antigonos says, I knew them and they were Levites.