Before taking the plunge into Protools, check Digital Performer. You can use it with any kind of interface compatible with OSX (unlike Protools) and it supports multichannel audio easily. You will need a multichannel audio interface, a MOTU 828 would be enough. http://www.motu.com

"The big difference between dts and dolby digital is that dts is full bandwidth in the rears, ie, all of the satellites, have the same full bandwidth output... where (and I'm just shooting from the hip here) dolby digital in ac3 stream is half bandwidth to the rears, which practically means left center right (rears) sub... or lower response... as a result, DTS is much more highly regarded for film... BUT "

Education is the key here..

DD 5.1 can set any channel at any level at any phasing sequence in percentile..

DTS, is good, carries a higher bandwidth sometimes but has a shelf peaking limit which can cause exceeeding distortions depending on the source..

On top of that, DTS is a variable bitrate compared to DD which is constant.

These fluctuations in variable may also cause glitches or "distortions" as the bandwidth of video and audio exceed their trnasport limit to the DAC. The higher bandwidth also allows for a "fuller" sound to the human ear.. so u will notice volume levels considerabely different on DD than DTS.. DTS is usualy about 10db improvement gain

Notice i say improvement...
reason being (in my opinion) DD metadata can sometimes be configured incorrectly to the environment its playing in..
For eg, a DVD encoded in a small room, is playing in a large amphitheatre for a film festival... to "wideness" is tightened by the metdata before the decoder can process the individual chanels.. thats jsut one example..

Rememebr that the DVD standard is the DTS is an ELECTIVE code bitrate, wheres PCM or DD is a requirement for DVD standard.. your DVD MUST include either one of these bitrates.. it cannot be provided on DTS alone.. (for comercial purposes.. )

Peter, dead on...
 

Certainly not trying to lead anyone, and I'm finding this discussion angling towards the differences in formats rather than how a dude, a computer, and a desire to make movies can pull it off... so..

Check this site:

http://www.audioholics.com/techtips/...lbydigital.php

which pretty much sums up what Peter was saying... while giving you a useful side by side comparison...

as far as my mistake, like I said, I was 'just shooting from the hip' with what I recalled being the practical difference between the compression methods.

You're absolutely right about the commercial requirements, which are fascist and monopolistic, since it is private industry saying you 'can't' produce surround sound of any format without paying dolby its due.

-but that's just my bleeding heart coming out ;)

thanks for the good info.

regards,
Rich