Table tennis after two sopranos push out pianos for choral revel (8)

I haven't cracked this one yet — but the brilliant team at Fifteensquared have:

[p] ING [p] ONG (another name for table tennis), with two S (abbreviation for soprano) instead of the two P (p = abbreviation for Italian piano = musical term for quiet). Singsong = a session of communal singing for pleasure.