True HD for your 360 add on!

[vinnyv07]

Great info BasicBlak. Thanks for the walkthrough. I can't wait to get my add-on rolling.

 

[BasicBlak]

Great info BasicBlak. Thanks for the walkthrough. I can't wait to get my add-on rolling.

Thanks BasicBlak, that was a pretty thorough explanation of how with only optical you are still getting better sound quality out HD-DVDs ( and this will work the same with BluRay movies). I really am looking forward to a AVR that supports HDMI 1.3 in 2007. Man, I am going to have to build myself a sound proof room or my wife is gonna kick me out!

My pleasure, folks! I gotta say, this add-on really is a godsend, an inexpensive (in the scheme of things, anyway) yet highly effective route to HD-DVD nirvana. Since my home theater still consists of one or two legacy components (namely my Denon 3600), I wasn't able to take advantage of Toshiba's HD-A1 player when it debuted last spring, as my AVR wasn't DTS-capable at the time. Why that was an issue for me is simple (well...not exactly): If you're using the optical or coaxial digital (S/PDIF) output on the Tosh and you select a Dolby audio track on an HD-DVD, the player converts that signal to PCM and then encodes it to DTS, the bitstream of which is then sent to the receiver for decoding. On one hand, I can understand Tosh's logic: The DTS bitstream would be decoded to playback full 1.5 mbps (approx. 1,539 kbps) resolution, more than doubling Dolby's core resolution of 648 kbps. However, at the end of the day, considering that there are still thousands (if not hundreds of thousands) of older DD receivers in operation today, they should have created a mechanism by which the consumer can make that choice based on individual needs. That fateful decision by the manufacturer is what ultimately shut me out of taking the plunge.

However, all was not lost. I bought my 360 console last spring knowing full well (via a little inside information, admittedly) that Microsoft would be issuing a stand-alone HD-DVD player in the fall. I also took solace in knowing that it would allow a full core DD bitstream to be passed via the 360's optical output, effectively putting my Ol' Faithful AVR back in play, so to speak, for HD. Aside from fantastic gaming, the 360 system really is a superb alternative for those with older equipment wishing to move up into the world of high definition software. Joe, you mentioned HDMI 1.3 in 2007. Well, that happens to be the reason I haven't upgraded my receiver yet after all this time. Aside from the fact that the 3600 is a helluva workhorse (they just don't make 'em like that anymore unless you've got $3K to $6K burning a hole in your pocket...and not many of us do, frankly), when I do upgrade, I like to sorta leave it at that for a while. Had I not waited for HDMI 1.3, I would have had to upgrade several times by now, first by acquiring an AVR w/DVI switching (which doesn't handle audio); then onto HDMI 1.0/1.1 (which hasn't been proven to consistently handle the new ultra-high-res Blu-ray/HD-DVD audio codecs). With 1.3, we'll finally be able to do EVERYTHING with one simple cable, and we'll be able to rest on those laurels for some time to come. But, for the time being, I'm in 360 HD add-on heaven...and I trust most everyone else who's gotten their hands on one of these babies is as well.

 

[Ilya]

Ilya, I thought you could pass pcm over the optical input? Seems that Toshiba issued a software upgrade that not only allowed the $499 unit to pass Dolby TrueHd 5.1 thru the optical but also pcm 5.1. Am I wrong on this?

No, unfortunately not. As others have already pointed out, optical or coax digital interface (Toslink, S/PDIF) standard only supports 2-ch PCM. Multi-channel sound can only be delivered in Dolby Digital or DTS (lossy) formats. The interface does support higher bit-rate for DD or DTS (up to 640 kbit/sec DD and up to 769 kbit/sec, or perhaps even 1,509 kbit/sec DTS), however, some older receivers may have problems decoding anything above 448.

The firmware update has enabled Dolby TrueHD decoding. But to take full advantage of it, you have to use HDMI (1.1 will do) with a receiver capable of processing multi-channel PCM off HDMI, like most Denons, or you have to use 5.1 analog outputs (which still sound much better than DD or DTS).

 

[Ilya]

it does pass the core Dolby Digital signal which is embedded in all TruHD and DD Plus signals.

I think you are confusing it with DTS-HD. It is DTS-HD, that has DTS in its core, so it is relatively easy for a player to extract core DTS from DTS-HD stream. As far as I understand, this is not the case with DD+ or Dolby TrueHD. You can't easily extract DD. You have to decode it first and then re-encode to DD. I believe this is why HD-A1 cannot decode DD+ to DD.

You are absolutely right that DTS and 648-kbps DD both sound better than 384-kbps DD. But even Dolby Digital Plus over A1's analog outputs blows both of them away!

 

[BasicBlak]

I think you are confusing it with DTS-HD. It is DTS-HD, that has DTS in its core, so it is relatively easy for a player to extract core DTS from DTS-HD stream. As far as I understand, this is not the case with DD+ or Dolby TrueHD. You can't easily extract DD. You have to decode it first and then re-encode to DD. I believe this is why HD-A1 cannot decode DD+ to DD.

You are absolutely right that DTS and 648-kbps DD both sound better than 384-kbps DD. But even Dolby Digital Plus over A1's analog outputs blows both of them away!

Perhaps my using the word "core" in describing DD may have been inappropriate; "traditional," for lack of a better word, might be more accurate. In any event, as Dolby Labs itself indicates in their white paper, DD+ does indeed include an embedded legacy DD signal encoded at 648 kbps, and this signal does get passed via the 360 HD add-on's optical output. Maybe the DD embedded signal in TruHD is done on a title-by-title basis, I'm not sure. I do know that when I select "TruHD" on the Training Day, Phantom of the Opera, and Superman Returns HD-DVDs (the only TruHD titles in my collection thus far), my Denon 3600 locks onto the signal as DD 5.1 via my 360 HD add on with a noticable improvement in fidelity vis-a-vis their standard DVD counterparts. Now, perhaps it's more of a hardware thing in that other HD playback devices may or may not pick it up...again, I'm not sure. But I'm getting excellent results nonetheless via my legacy components. The point I was trying to make was, for those of us who aren't yet equipped for true DD+/TruHD playback via 5.1 analog or HDMI, you can still get upgraded sound from HD-DVD on the 360 HD add on via optical/coax as a result of each codec's full resolution. You may be correct, though, in that your mileage may vary depending on how old your receiver is. My guess is, the incompatibility issues might be somewhat sporatic, as my 3600 is goes back to mid-90s and works like a charm.

 

[BasicBlak]

These references should help to clarify things a bit....

http://www.dolby.com/promo/hd/connector_diagrams.html

http://www.dolby.com/consumer/technology/trueHD/AVRs/trueHD_avrs_2.html (Refer to the section entitled "S/PDIF Connection")

 

[BlackHitachi]

These references should help to clarify things a bit....

http://www.dolby.com/promo/hd/connector_diagrams.html

http://www.dolby.com/consumer/technology/trueHD/AVRs/trueHD_avrs_2.html (Refer to the section entitled "S/PDIF Connection")

Thank you BasicBlak great help once again!!