[DCP-o-matic] DCP-O-MATIC volume question

Hello Carl, thanks for creating such a great piece of software,is there any way to adjust the volume of a DCP? we tried to play the DCP on one of our projectors but the volume was much too loud. the video is an ad so and will be played next to other ads and trailers so we cant adjust the volume on our server or else it would affect everything else. any help here would be greatly appreciated! thanks. -Aaron