Used with FSOUND_Reverb_SetEnvironment and FSOUND_Reverb_SetEnvironmentAdvanced, this can
be placed in the place of a specific parameter for the reverb setting. It allows you to
not set any parameters except the ones you are interested in .. and example would be this.
FSOUND_Reverb_SetEnvironment(FSOUND_REVERB_IGNOREPARAM,
FSOUND_REVERB_IGNOREPARAM,
FSOUND_REVERB_IGNOREPARAM,
0.0f);
This means env, vol and decay are left alone, but damp is set to 0.
FSOUND_REVERB_IGNOREPARAM
-9999999 /* used with FSOUND_Reverb_SetEnvironmentAdvanced to ignore certain parameters by choice. */