DTS Audio Distortion

The only way to pass DTS Master or Dolby TrueHD is over an HDMI cable either as Bitstream or PCM. You can also use a 5.1 - 7.1 analog connection to pass PCM to the receiver which your receiver is capable of but your BD player is not. So your only choice is to use the Digital Coaxial connection which will pass the core DTS Master signal to your receiver, better than regular DTS but not DTS Master. Page 23 of the BD manual say to select the PCM down mix for the digital connection. 

 

Getting a new receiver may be the best option, but it isn't the only one. Lots of people are still using older receivers that lack HDMI connections with Blu-ray. The DTS core delivered over coax from a DTS-HD Master Audio track should sound quite good.

 

What's interesting here is that you seem to get good sound from some Master Audio tracks and bad sound from others. It might help if you gave some examples, because this is a problem I don't recall hearing of before. Maybe someone else has.

 

 

 

 

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.

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.

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.

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.