PHILADELPHIA — What do you do if you buy a famous downtown department store and find an organ with 28,482 pipes occupying thousands of square feet of perfectly good retail space?

If you’re Macy’s, you let devotees of the instrument put in 61 more pipes and give them thousands more square feet to set up an organ repair shop.

Diapasons, it would seem, are as much music to Macy’s as cash registers, coin counters and customers at its Center City store here, a Philadelphia institution that was originally a Wanamaker’s. So the company let the Friends of the Wanamaker Organ, a private group of aficionados who have been helping to maintain the instrument for years, install another stop and set up a repair shop after Macy’s took over the store.

“Every lunchtime, people hear the organ and feel good — and people are in a mind to shop when they’re feeling good,” explained James Kenny, the store manager. “It’s the ultimate feel-good experience.”