Yesterday, I had bobliinds and his lovely wife over to watch LOTR, "U-571" and "Gladiator" in DTS, in comparason to Dolby Digital. My Sony DVD player does not pass the DTS signal, so I wanted to listen for any differences. He brought his DVD player and we plugged it in. I have heard DTS before, and am familiar with it's effects, but not in my home theater setup.

Was there a difference? Yes., very definately, and for the better. But there are some important things I noticed.

The most obvious was an increased sibilance to the entire sound presentation. This should not be an artifact of DTS per se, and it almost certainly had to have originated somewhere else in the conversion to DTS.

Another thing that I heard was that the surrounds were higher in level. This was not just a subjective judgement. I have monitoring meters on each channel for when I do mixes, and the difference could clearly be seen. The level difference was probably around 3db.

The overall mix sound level was also a few dbs higher in the DTS than the Dolby Digital.

The DTS had a more fluid sound presentation, and preserved more of the partials of the voices, instruments and sound effects.

However, I am very "imprinted" with the sound that is heard on a dubbing stage, having heard the original master sound "units" of various films on an almost daily basis, and based on this, I would have to say that the Dolby Digital version was closer to the sound that was originally heard when the film was mixed. The DTS by comparason, while soundng preferable, sounded "enhanced" over what it should have.

Then we performed an extremely interesting comparason. Having performed the restoration of the music for the DVD of "Superman" I have the original 24 bit masters of the music for the film on hard disc. On the DVD, there are several un-cut pieces of music from the score I supplied as bonus material, that are encoded in Dolby Digital. We decided to compare the two.

This was an especially valid comparason since I mixed the music for these tracks in my home theater, and on my speakers. I supplied the DVD authoring studio (Warner Bros Studios, Hollywood) with digital 24 bit files of my mixes to be encoded for the DVD. This is significant as the geneology of the journey from mixing studio to finished DVD is completely known. The mastering engineer was given strict instructions by me to do nothing to these tracks other than encode them into Dolby Digital for the DVD.

So we cued up the bonus tracks on the DVD with their original 24 bit masters residing on my ProTools digital audio workstation. The switching was performed by an 8 channel mechanical (nitrogen filled with gold contacts) relay, so no added electronics were in the signal chain.

Differences? DUHhhhh!! This was not a subtle comparason. The most glaring difference to me was that all the "partials" of the musical instruments were stripped away below a certain threshold, and replaced by what sounds like "sandpaper". This was really bad. The 24 bit masters on the other hand sounded full, rich, and smooth all the way up and down the tonal range, regardless of subtleness of the details. It sounded like music, with no grittiness added. Instruments like trumpets and trombones especially had the subtle detail of their harmonics preserved, where they sounded like "grit" on the Dolby Digital version. Not surprisingly, as the music got denser and louder, the worse the Dolby Digital version sounded when compared to the pristine 24 bit master.

Perhaps an even bigger suprise was that the dynamic range of the Dolby Digital version was severely limited. This was not a subtle difference, but one that was so obvious that I had to ride the volume control of the Dolby Digital to keep the volumes equal on loud passages!

Bobliinds and his wife were able to tell which version was playing 100% of the time: the difference was that obvious.

This comparason is enlightening since we can only hear the finished soundtrack on DVDs and in movie theaters in Dolby Digital or DTS (or sometimes SDDS) - there is no alternative!. And make no mistake, DTS is a lossy medium too: not as bad as Dolby Digital, but nowhere as pristine sounding as the uncompressed masters. I have taken the "sonic penalty" of both of these compressed formats for granted, since I hear their results regularly, and have as a reference the sound of the original masters, but with nothing to compare to, the average listener has no idea how comprimised these formats are. I'm afraid that until motion picture soundtracks are delivered on some future format uncompressed, we are going to have to live with less than optimum (to put it mildly!) sound.

Perhaps Bobliinds would like to chime in on his thoughts about this comparason.


[This message has been edited by soundhound (edited February 07, 2003).]