From Longman Dictionary of Contemporary Englishpound something ↔ out phrasal verbto play music loudly The Rolling Stones were pounding out one of their old numbers. → pound→ See Verb table
Examples from the Corpus
pound out• Otis's costs could have amounted to hundreds of pounds.• Hence, a pound paid out is worth more than a pound retained and reinvested.• Is a little sleeplessness and fist pounding so very out of the way?• But there were almost nine hundred malicious calls, which cost the brigade over a million pounds to turn out to. 