I found no volume control script for VX (turns out there are others) so I wanted to port Ru/むっくRu (Rutan) one, but gave up mid way and made a simple one that uses game variables.
With this script you can define a master volume for BGM, BGS, SE and ME by editing constants in the script, or control the volumes via game variables (you will need to initialize those variables on a new game if you don't want 0 volume, main many screen will not be affected)
Features
Set Volume of BGM, BGS, SE and ME
Terms of Use
Free for use in non-commercial projects.
Free for use in commercial projects.
Please provide credits to Zero_G and むっくRu (Rutan).
Credits
むっくRu (Rutan) for volume change methods
Changelog
v1.1 - Fixed a crash when restarting (thank you kyonides)