Does MP3 compression decrease the effectiveness of BSS audio?
Not in most cases. MP3 compression and fiddling with the sampling rate can cause some higher frequencies to be deleted, which can affect certain BSS functions such as low-pass filter modulation. Also, if you compress BSS audio to mono mp3, all Crossfeed and Auto-Pan Modulation will become ineffective. To be sure that no effectiveness is lost during mp3 compression, stick with 56kbps+ and stereo. 128kbps is recommended. 44100 sampling rate is also recommended.