On Thu, 7 Apr 2022, Ignition Films via DCP-o-matic users wrote: Thanks for the kind words and the donation! If you enable the Mid-Side decoder it will take the first two channels of your audio (probably left and right) and process them to produce left, right and centre according to some reasonably straightforward maths: Output left and right = (Input left - Input right) / 2 Output centre = (Input left + input right) / 2 In terms of sound this means we put the things that are common to the left and right inputs into the centre, and the differences go into the sides. It's a fairly reliable way to create a centre speaker from "nothing" as it were. In this case you could reduce the DCP channel count to 4, but it's not so important because any unused channels will be made silent anyway (and your DCP will take up a lot of disk space much more because of the video than the audio). This is similar to the mid-side decoding (but not quite the same). -6dB should make the centre the same as it would be with the mid-side, though your left and right channels will be a little different. The way it sounds would depend on the source material but I would guess it would be not make a massive difference. You could indeed make something come out of every speaker in this way. But making what you might think of as a "real" 5.1 mix is not so simple - putting the same audio in every speaker is not enough. Indeed, doing that is quite likely to not sound very good. In my humble opinion it is better to leave the surround speakers silent than to fill them with some signal which is more-or-less the same as that in the left and right front speakers. All the best, Carl