I know alot of sound difficulties can be experienced on ventrilo, so here is a simple method of increasing an individual on vent.
first off sign into vent, the correct server and join the conan channel, (not neccessary for this, but its regualr to do so)
then on the right hand side of your ventrilo window you should see a 'setup' click that.
When this window has opened you will see 'use direct sound' click this so it is enabled.
now once you've done this, you need to click 'OK' and now for the second bit
right click the individual you wish to turn up and click miscellanious-special effects
now another menu has popped up with a list of things in the right hand side, select volume and click add
now just double click volume on the left hand side and select the volume level you wish that individual to be at, simple eh