How to decrease audio quality without losing channels.?

[IamLEGEND]

Hi to all seven forums. hope all will be fine.
guys I extracted an audio from a mkv movie using mkv merge gui, and this is the audio status.
.
Complete name : The Green Hornet 2011 1080p BRRip.mkv
Format : Matroska
File size : 366 MiB
Duration : 1h 54mn
Overall bit rate : 449 Kbps
Encoded date : UTC 2011-06-13 20:10:53
Writing application : mkvmerge v3.3.0 ('Language') built on Mar 24 2010 14:59:24
Writing library : libebml v0.8.0 + libmatroska v0.9.0

Audio
ID : 1
Format : AC-3
Format/Info : Audio Coding 3
Mode extension : CM (complete main)
Codec ID : A_AC3
Duration : 1h 54mn
Bit rate mode : Constant
Bit rate : 448 Kbps
Channel(s) : 6 channels
Channel positions : Front: L C R, Side: L R, LFE
Sampling rate : 48.0 KHz
Stream size : 365 MiB (100%)
Language : English
.
now, I wanted to convert it in some lower bit rate, which were exactly decreasing the size of it. that is I wanted to do, but the problem is, if I convert it to any audio format it will be done with only 2 channels audio. I want to decrease some of its bitrates/size like 196kbps or 160kbps with the 6 channels..
plz guide me how I do that job.

 

[Rxx]

To mess with more than two channels, you might actually have to pay for a program that can do it. I believe Nero has a wave editor that supports six channels in their multimedia packs. Sorry this isn't much help.