electriczombie

Sound question with Toshiba HD A2

I'm pulling my hair out and would appreciate a quick response.

I own a high-end Onkyo receiver with 1 Coax, 2 Toslink and 1 Ac-3 RF input. (NO DTS, just Dolby-Digital) When I play a movie with DOLBY-DIGITAL PLUS, there is absolutely no sound coming from my receiver and the yellow DOLBY DIGITAL light does not come on. It DOES come on when I play the side of the disc with Standard definition (why would I want that?) and Dolby Digital 5.1 as an option.

Settings:

SPDIF: Bitstream
HDMI: Auto

So at that point I have two options:

1. High Definition with 2 CH Analog Out
2. Standard Definition with 5.1 Dolby Digital

And then I set the machine to the PCM option, and then this is what happens: I get the High Definition picture and WHAT SOUNDS LIKE 5.1, but the yellow Dolby Digital light does not light up.

I have read various posts on this issue all evening. Some suggest that I am getting a down-converted DD+, (etc) through the PCM option, coming out of my receiver as 5.1, but not dolby-digital. The sound is excellent, and absolutely all speakers, including the sub are active, but I'm not sure the sound is true 5.1.

Other posts suggest that without the DTS encoding (which the Onkyo does not have) I am really getting 2.0 or Pro-Logic through the optical cable.

Can anyone clear this up for me? E-mail me at: brokentoyproject@columbus.rr.com.

Thanks in advance.

Jack Gilvey

Re: Sound question with Toshiba HD A2

As far as I'm aware, for transmission over SPDIF (optical or coax) the A2 downsamples all the HD audio formats to a DTS stream. Without DTS, you won't get discrete 5.1. If you set SPDIF to PCM, it's sending a stereo PCM signal, so your receiver is deriving 5.1 via Pro Logic.
DTS was chosen due to its higher designed bandwidth to preserve as much resolution as possible after the downsample with existing receivers. I don't think there's a way to get a regular DD signal from the HD disc unless one's included, but I haven't seen this.

Thomas W

Re: Sound question with Toshiba HD A2

I believe this is the reason some people get the X-A2 model rather than the A2. The X-A2 has the 5.1 analog outputs that can handle Dolby Digital Plus and Dolby Digital TrueHD tracks. The A-2 doesn't have 5.1 analog output, so the only other way to get these formats on the A-2 model is through an HDMI connection to your receiver. If your receiver doesn't have HDMI then you must use the coaxial or optical connections.