You can't just "make another bank", the sound driver is hardcoded to only look in two banks for music, one of which has the continue music and a bunch of random stuff, and the other which has all the rest of the music and the sound effects. What you can do, is try setting the sound effects in a new bank, which will give you a bit more space for music, or move it to the continue bank and move around the assorted art to get more space. Note that if you put music in the continue bank, you need to use a specific notation in the Z80 playlist section of the sound driver (see the continue music for details). Or, you could replace the sound driver entirely, such as the Clone Driver (works like Sonic 1), the KEH sound driver with multi-bank management system, or even the S3K driver. Also, when importing music to Sonic 2, you need to either use SMPS2ASM and set the 'uncompressed' flag in the Z80 playlist, or convert the song into the Sonic 2 format with a base address of 1380 and compress it as Saxman (with size). You can't just drop a Sonic 1 format binary into the ROM and expect it to work.