Unless you are sending the audio from the PS3 to a DTS capable receiver, you will have to use a free program called MKV2VOB. Check the box that says älways transcode DTS to AC3" and the program will turn the file into an AVC + AC3 file. It works very fast (just a couple minutes) and does not affect the video.
Double check audio options on PS3 when playing the file. Make sure both left+Right are enabled and volume is set in middle as "normal" any other setting in here will cause white noise. 99.9% of the time the PS3 audio settings (from the triangle button during playback) are the cause of this.