This patch fixes sound problem on models with discrete ym2612 (most of models 1, and VA 2.3).
This patch upgrades GEMS sound engine to v2.8.
Database match: Batman Returns (World)
Database: No-Intro: Genesis (v. 20180824-045026)
File/ROM SHA-1: B173D388485461B9F8B27D299A014D226AEF7AA1
File/ROM CRC32: 4A3225C0