What is "Sar ha'Leviyim b'Masa"?
'Rashi': It is an officer regarding singing. Radak ? "Masa" is like "va'Yisa Es Kolo" (Bereishis 29:11). He was greater than all of them regarding song. Malbim ? this song is called Masa, for they bore words of praise via parables and metaphors.
Radak: He was great in Nevu'ah.
What is "Yasor b'Masa"?
'Rashi': He rectifies them to make the song pleasant, if they must raise their voices or lower them.
Radak: This is like Yasor with a Sin (overpowers in raising the voice). Similarly, "Sarei Sorerim" (Yirmeyah 6:28) is as if it says Sarei with a Sin.
Malbim: He made a band of the singers. They arranged the song according to him; they began and ended based on his mouth. This is like "Mi Yesor ha'Milchamah" (Melachim I, 20:14) ? who will arrange the ranks of war and tie them together?
What is the meaning of "Ki Mevin Hu"?
'Rashi': He understands music. Mevin applies to learning music ? "Melumdei Shir la'Shem Kol ha'Mevin", "va'Yapilu Goralos? Mevin Im Talmid" (25:7-8).
