Half bit-rate DTS soundtracks inferior?

Andrew_Ballew

Second Unit
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Feb 21, 2002
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294
As I move up into the world of seperates and the quality bar is raised bit by bit (No pun intended), I am noticing a real trend. I am noticing that DTS soundtracks encoded at the 754kbps bit rate sound very compressed and shrill in the upper frequencies. So much that it can be ear-shattering at times. It makes for a very unpleasant experience.

I really began to notice this with the inclusion of a Rotel RSP-976 as my pre/pro. I noticed this to some extent with my old Sherwood Newcastle AVP-9080, but not to the extent that could actually pinpoint half-rate DTS as the culprit.(FYI, I power my Rotel with a Carver 806x amp, and have Def Tech speakers.) The Rotel is no doubt the "brightest" processor I have owned, and is very, very detailed and revealing of the source element. It is an excellent processor, and plays in general with a tonal balance and a dynamic range that is unsurpassed by anything else I have owned. Dolby Digital soundtracks shine on this unit- they have never sounded better. DTS soundtracks encoded at the full bit-rate shine as well- they are outstanding- perhaps the most outstanding soundtracks I own. But these half bit-rate DTS discs are really bothersome in their harshness.

Has anyone else experienced the same? Of course, all of our equipment varies, likewise every user experience is different and incomparable in the strictest sense. I at first thought ALL DTS tracks were the problem, and that the problem must lie in my processor. But when I discovered that full bit-rate DTS does not exhibit the same problematic behavior, I all but ruled out my processor, although I admit that it might still be a contributing factor- I am fairly sure it is not, though.

Not all half bit-rate DTS tracks are as bad as others, though. Some are listenable, others are not. They all share this bright, shrill compression-like harshness in the upper end, though, to one degree or another. Yes, even the refernece track Saving Private Ryan DTS. It is one of the least of the offenders, granted, but it still offends.

Waiting to hear your responses.

Andrew B.
 

Ned

Supporting Actor
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Feb 20, 2000
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What are your room acoustics like? Don't blame the messenger when it could be something else.
 

Lewis Besze

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Jul 28, 1999
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Not all half bit-rate DTS tracks are as bad as others, though. Some are listenable, others are not. They all share this bright, shrill compression-like harshness in the upper end, though, to one degree or another.
Actually on some of the charts I've seen,the 754kbps rate DTS rolls off just a bit above 15khz gradualy[very shalow],so your impression is just the opposite,which I don't share at all.The Haunting,or Atlantis SE and JP III are all good examples of good quality sound at this compression rate.

I think the term "compression" is being used in a rather liberal fashion these days to "blame" just about any aspect of digital audio,without examining other factors as well.
 

Neil Joseph

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There was a thread and survey about this some time back. It claimed that in blind tests, fullbitrate dts was preferred, then DD5.1 448kbps, then dts 1/2 bitrate was third. It was a long time ago, probably when 1/2 bitrate dts was making it's appearance and probably around the time Saving Private Ryan was released.
 

Robert George

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Jul 3, 1997
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Your ears don't lie. Indeed, as the quality of one's system improves, and the quality of one's listening improves, subtle variations become more noticeable, even if we can't exactly articulate what we are hearing.

Personally, I have never heard a 754 kb/s DTS track that I preferred over a DD 448 encoding of the same material (same mix, same master). The two most often cited examples of the potential quality of DTS at 754 kb/s, Saving Private Ryan and The Haunting, are not available with the same soundtrack master encoded in DD 448 kb/s for a fair comparison.

As you will see, this is a subject that has been debated to death and few opinions have been changed. We all have our preferences based on whatever we as individuals base those preferences on.
 

Michael St. Clair

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May 3, 1999
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I'm guessing that the DD5.1 track on the laserdisc of SPR does use the DTS mix.
I'd rather see DTS as it was in the laserdisc days. Separate releases, full bitrate, no foreign language tracks, no DD5.1 track, no commentary track.
Even better, let's see Disney, Paramount, Columbia start taking the movies they butcher themselves and licensing OAR transfers to DTS for separate release.
 

Andrew_Ballew

Second Unit
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Feb 21, 2002
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294
In regards to compression being a culprit in the reduction of sound quality, I have always equated compression artifacts in a recording to "holes" being in the sound- it sounds like something is missing. The very best example is with MP3's. That is what I am hearing in the high frequency range of these DTS recordings. It is as if there are lots of "holes" in the high frequency areas. This leads to a shrill, almost tinny aspect to the sound that when played at high volumes can be unpleasant. Perhaps there is indeed a high frequency roll-off on these DTS tracks, but that cannot hide these "holes" in the sound.

I obviously am not the most technically astute at putting what I am hearing into words-but I know this much- in my current listening environment with the Rotel RSP-976 as my controller, DTS at 754 kbps is in my ears quite inferior to Dolby Digital. DTS at full bit-rate is still the king, though. I believe that DTS themselves begrudingly admit that their format at the 754k bit rate is not transparent.

Again, I am not ruling out my equipment as the problem. In the past on what is considered to be less revealing equipment, I have thoroughly enjoyed DTS in its higher compression form. But as long as this Rotel is my head unit, my ears tell me that Dolby Digital sounds glorious in comparision to 754k DTS. Perhaps all this will change again when I get my Outlaw 950, if it ever comes, haha. On a serious note, though, that is exactly the reason the kinds of comparisons are difficult based on various user experinences- we all have different equipment that does different things to the final product we are after- great sound.

Cheers

Andrew B.
 

greg_t

Screenwriter
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Jan 18, 2001
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On my humble system, I did a listening comparison between DTS saving private ryan and the two minute or so clip on the DTS demo 4 dvd, which is full bitrate. I really didn't hear much of a difference between the two, it seemed as if the demo was a bit "fuller" sounding. But that could also be equated to dts possibly creating a better mix for the demo than was done for the half bitrate production dvd.
 

DaViD Boulet

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Feb 24, 1999
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What are your room acoustics like?
Well then wouldn't that make *all* his soundtracks have the same anomoly?

He clearly states that full-bit-rate DTS sounds fantastic and the DD sountracks have no shrill brightness too. It's obviously *not* a function of room treatment or lack thereof.

My guess is Andrew is hearing the sound of typical 1/2 rate DTS and your system is just being very revealing. Oddly, I have found that I *like* the sound of DTS more that the usual DD but I have no way of knowing which bit-rate is being used on a given title. Moulin Rouge and MIB sound great. Of course...for those of you who know...are those 1/2 rate or are they really full bit rate???

-dave
 

Shane Martin

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Sep 26, 1999
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While I agree with Obi's first statement I don't with his second.

I'm guessing that the DD5.1 track on the laserdisc of SPR does use the DTS mix.
From what I've been told that is incorrect. There are 3 seperate mixes for SPR. I've heard them all and the DTS DVD is the best, the DD LD is close behind and the DD dvd is far behind in 3rd.
 

ChrisA

Second Unit
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Nov 25, 1999
Messages
478
This thread is yet anothe example of why people must unite and sign the HD-DVD petition!

The HD-DVD petition clearly covers the audio expectations from HD-DVD in a logical, concise, and professional manner.
 

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