whenever i open another program, specifically guitar rig, the music in foobar plays louder.

it returns back to normal when i manually change the song or stop playback.

guitar rig uses asio plugins. foobar's output device is my soundcard.

i use .9b13

why do i get a volume boost?
and how can i keep this boost while using foobar without opening the other program if possible?

I just had the same thing happen to me. I was listening to foobar .9b13, when i opened a .mpg file. when the .mpg began to play, foobar about tripled in volume. btw, the .mpg file opened in powerdvd 6.

Because Power DVD raises the global Windows volume and thus in any program that's running. I myself have a problem of volume becoming unstable: it unexpectedly goes up or down, and I don't run any additional sound playing programs. I use a Soundblaster Audigy 2 ZS Pro. Any ideas?

AFAIK, in PowerDVD, there is an option to not remember the last used volume setting. Or was it WinDVD? Well, look around for such an option.