I'm a bit curious about how digital surround works, esp in regards to Logic. specifically: 1) does encoding into an AC-3 file do any signal processing to the channels aside from multiplexing the audio? a) if any signal processing is needed, does Logic do it for you? b) does the decoder do any processing other than de-muxing? 2) is the .1 sub channel just a regular discrete audio channel, or do I need to do some filtering on it before I encode? a) what kind of filtering? b) if not, is that low-freq processing handled by the speaker or the decoder? Thanks for any info. _______________________________________________________ Eric Oehler / wonko@... / www.nulldevice.com Synthetic music for synthetic people.