This hack changes the clapping instrument (heard inside the Tennis Acedemy Lodge for example) to the one heard in Mario Golf: Advance Tour. It is basically a higher pitched version of that instrument.
Database match: Mario Power Tennis (Europe) (En,Fr,De,Es,It)
Database: No-Intro: Game Boy Advance (v. 20180816-092117)
File/ROM SHA-1: D61990974040D405B5BF8436AC8E1E0BEB0F7964
File/ROM CRC32: C8DB4F60
Database match: Mario Tennis - Power Tour (USA, Australia) (En,Fr,De,Es,It)
Database: No-Intro: Game Boy Advance (v. 20180816-092117)
File/ROM SHA-1: 794584ACBD15A69FB9AC760C0A6F48095805BD59
File/ROM CRC32: DA192D29