Reduce Bass in BD rips

I've been ripping my Blu-Ray movies to my PC for purposes of setting up a media centre but all my files have extremely loud, booming bass while extremely quiet dialogue irrespective of the playback device. On my TV for example I'd have to set the volume to 40-50 to hear them speak but drop it down to 20 when action scenes start due to the bass.

I use SlyDVD for my rips and RipBot for my converts. What is the best way to reduce the bass level for my existing mkvs/mp4s as well for any further converts I do down the road. Thanks