Tense? My rising alarm shuts out constant sources of drumming (7)

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

T (tense), then MY reversed [rising], PANI{c} (alarm) [shuts out constant]. Apparently this is an alternative spelling of ‘timpani’ – kettledrums. Since the Y is unchecked this clue may prove to be something of a beartrap for speed solvers who don’t bother to parse everything fully as they go.