final fantasy mystic quest sound effects

A simple way to do this is to have the SPC pointers for all of the music in the ROM to point to the first entry which is silence--this is how I rip sound effects from every game.  Then you can use Byuu's cycle perfect SNES emulator Higan (https://byuu.org/emulation/higan/) to have the sounds played as high quality and accurate as possible.  If your computer cannot run Higan use SNES9x next because ZSNES sucks for everything.

Attached is a picture of the location of the SPC pointers in MQ, each pointer is 3 bytes long so you need to change starting at offset 6BDB1 and go through 6BDFE in a ROM without a header.  Don't go over because starting at 6BDFF are BRR pointers.  

0D 85 0E is the pointer data for the silence "music".  So to make it easier you can copy/paste 26 of these (78 bytes) worth (below) and paste it in your hex editor after you've selected the exact byte range @ 6BDB1-6BDFE.

Code:

0D850E0D850E0D850E0D850E0D850E0D850E0D850E0D850E0D850E0D850E0D850E0D850E0D850E0D850E0D850E0D850E0D850E0D850E0D850E0D850E0D850E0D850E0D850E0D850E0D850E0D850E

Out of curiosity what sound effect are you looking for?