DTS Audio Distortion (1 Viewer)

[DaBod]

I recently upgraded to blu ray and purchased a Sony BDP-S580. I have it running audio via coax to my Sony DA555ES receiver and noticed over the weekend that certain movies produce a significant amount of audio distortion, specifically in dialogue. This only happens when the disc is encoded with DTS Master HD audio (anything in Dolby sounds fine). I read somwhere that while my receiver can process DTS, it (because it is a little older) cannot process DTS Master HD. Could that be the case? When I go into the audio settings on the blu ray player my only option is to downmix to PCM, and thus I lose DTS. If what I read is correct, is there any possible way to fix this without the purchase of a newer receiver? I am still fairly new to home theater systems, so please excuse me if some of my terminology is incorrect.

 

[DaBod]

Thanks much! I was kind of afraid that the best option was to get a new receiver that has HDMI capability. Any idea why some sound just fine in DTS and others terrible?

 

[Michael Reuben]

Originally Posted by DaBod

 

[DaBod]

Originally Posted by Michael Reuben

The distortion is much more prevalent in dialogue...sound effects sound fantastic. I noticed a significant amount of distortion in the movie Secretariat, however little or no dialogue distortion came through in Master and Commander or Knight and Day...all three of which were encoded with DTS Master.

Don't get me wrong, the PCM downmix still sounds really good, I am just spoiled by seeing the blue multi-channel decoding light on my reciever. Would it be possible to bypass not having an HDMI input on the receiver by simply sending both audio and video through the HDMI to the TV and then audio out from the TV to the receiver via coax or optical? Or might that put me in the same boat I am in now?

 

[Jason Charlton]

Running the audio through the TV would put you worse off than you are now.


Lossless audio can only be transmitted via HDMI or through the use of multichannel analog outputs direct from the player. Digital optical and coaxial cables can't carry Dolby TrueHD or DTS-MA audio tracks.


In addition, 99% of TVs will downmix any digital multichannel audio from external sources to 2.0 stereo before they output the signal through their digital optical or coaxial connections. You'll only get multichannel audio out from your TV for programming picked up using your TVs internal tuner.

 

[rsteer]

I've had similar problems ever since I bought my Blu-ray and HDTV about a year ago. I'm using a Panasonc BDT100 feeding audio via optical cable to an old Nakamichi 5.1 receiver, which I'd like to keep using because the audio quality of the Nak is superb, and 5.1 is enough surround channels for me. (TV is Panasonic P50VT25, but that's irrelevant here.) I believe I have the BDT100 set to use PCM output on the optical link. I've noticed a "burbling" type of distortion in the center channel (and I think ONLY in the center channel) on some movies, and recently noticed that it seemed to be only DTS-MA soundtracks. (Since the center channel is where most of the dialog is, the effect is as the original poster wrote, that it distorts the dialogue.) I'd have to spend a minimum of $600 to come close to the Nakamichi in audio quality (best I could find that's affordable is a last-year's Marantz model). It seems almost as expensive to find a decent BD player with 5.1 or 7.1 analog-out. Would there be any difference in using a coax connection instead of optical? My impression is that they carry the same info.

 

[Jason Charlton]

There really is no difference in the signal that is carried by the digital coax vs. the digital optical. That being said, I think the mechanical connection for a coaxial cable is generally better than the optical cable and less susceptible to problems, so giving the coaxial cable might be worth a try (at least they're cheap cables and you're out only $5 if it doesn't work).


I will also add that I am one who puts more stock in the speakers affecting "sound quality" than the hardware, particularly if you're the type of person who prefers to listen to sound in its "native" form without additional signal processing. Digital audio is digital audio. Yes, with lossy DD and DTS encoding, there is "wiggle room" for precisely how the signal is decoded, but that brings me to my final point:


I think you're greatly discounting the improvement the lossless audio FORMATS provide over their lossy counterparts. This goes far beyond the fuzzy notion of "sound quality" - there is a definite, quantifiable benefit of going with lossless audio versus lossy audio.


In fact, I would say there is a pretty good chance that a mid-level receiver from Onkyo, Denon, Pioneer, or Yamaha with Dolby HD and DTS-MA support via HDMI would have a overall better sound than your Nakamichi with lossy DD or DTS audio (even the higher bitrate tracks contained on Blu-Ray).


To me, the improved sound quality was easily the most noticeable improvement of Blu-Ray over DVD. Of course, I have only a 720p front projector display, so to this day I still am not realizing the full video benefit of BR, but still - the audio is what got me hooked on Blu.


Good luck with whatever you decide - if nothing else, I hope the coaxial cable solves your problem for now.

 

[rsteer]

Thanks for the comments -- helpful. I use the receiver for regular music as well, and when I replaced a Denon with the Nak (same speakers) I could hear a really big difference in clarity, depth, all kinds of things. Most consumer brands of multi-channel receivers -- even Denon and Yamaha -- are designed for consumers who think that MP3s sound just fine, and can't match the low distortion and dynamic range, especially on the surround channels -- they expect people to be using "home theater" speaker bundles. I use 5 floor-standing speakers -- the front 3 go down to about 30 Hz so even without a sub there's a good deal of rumble. They benefit from the fact that the Nak has 5 identical channels, so even the rear channels have 100W RMS with, I think, something like 0.01% THD. What you've said about the newer formats does suggest, however, that if and when I can afford to get a newer receiver that comes close to the Nakamichi specs, at that point I would probably hear another incremental improvement in sound quality.