Additional delay in music modes are just to increase the size of the venue. If they are set to 0, all ambiance would reach the listener at the same time as the primary source of sound, thereby not creating any sense of ambiance at all. You have to set those delays at a position where you feel a sense of space, but not to the point where it seems to be a seperate source of sound.

To do that, you should start with the delay at 0, set the surround channel's level set at +10 or so & the filter to off, play whatever music you listen to apropriate for that DSP mode, then gradually increase the delay until it sounds like an echo coming from the surround channels. That would be your maximum delay allowable. Then you would decrease it to what you feel the proper size of the venue should be, change the filter setting until you cannot localize the surround speakers (I usually set it at 7khz) then decrease the surround level until you feel it is the right type of venue (you might want to set it to a few dB above the default if you want to hear the room, since modes like Trifield and Music utilize ambiance very subtlely.)

Ambisonice requires no delay, since the reproduced side and rear channels are the actual hall ambiance arriving from that direction as recorded by the microphone.

As far as DD/DTS w/movies, they should probably be set to 0, since nothing ever sounds natural in the movies anyway, music frequently sounding like the old quadraphonics (w/different instruments coming from different channels,) a soundfield that reach the listener from all the speakers at the same time would probably be required.

[This message has been edited by lwang (edited 01-01-2002).]