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Posted Fri Jul 9, 2010 at 11:30 AM PDT by

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Answers by Joshua Zyber

Dolby ProLogic IIx vs ProLogic IIz

Q: Some new receivers have Dolby ProLogic IIz processing. What's the difference between ProLogic IIx and ProLogic IIz? Is IIz just a newer enhanced version?

A: To answer this, let's take a look at the history of Dolby ProLogic. The original ProLogic was a processing program used to derive surround sound from a 2-channel audio source. Using a matrixing algorithm, ProLogic could extract the dialogue from a movie soundtrack and direct it to a front center channel, and likewise could extract (at the time, monaural) surround information and send it to the back speakers. In effect, ProLogic made a 4.0 soundtrack (Left, Center, Right, and monaural Surround) from a 2-channel signal. In the home, this worked great for VHS and Laserdisc sources. And we still see some DVDs and Blu-rays authored with 2.0 soundtracks, depending on how the movie or TV show was originally mixed.

Later, the company created Dolby ProLogic II as a refinement of the original process. ProLogic II added stereo directional steering to the surround speakers and an LFE channel. That 2-channel source could be processed into simulated 5.1 format.

Next came ProLogic IIx, which expands to 7.1 by adding left and right center back channels. ProLogic IIx processing can be used to bump either 2.0 or 5.1 sources up to 7.1. It can even be applied to soundtracks from the competing DTS audio codecs. This has been the standard in most A/V receivers for a few years now.

Dolby's latest twist is ProLogic IIz, which adds new height channels. The idea is that you can mount two small speakers above your front Left and Right mains. ProLogic IIz will then extract ambient or amorphous noises such as wind or rain and send them to the high speakers. This can be added to either 5.1 or 7.1 systems. Dolby refers to the latter as a 9.1 configuration.

I have to admit to some skepticism about the usefulness of height channels. No movie soundtracks are actually mixed with discrete height information. I suppose that the benefit of this will largely depend on the room environment. Some viewers may find this very effective. But I believe that the majority of listeners will continue to find 5.1 or 7.1 set-ups perfectly satisfactory.

Processing 5.1 Soundtracks into 7.1

Q: I have a new 7.1 channel home theater set-up. However, I find that there are hardly any Blu-rays that are encoded with 7.1 DTS-HD Master Audio or 7.1 Dolby TrueHD soundtracks. How do you reviewers – those of you who have 7.1 set-ups – treat Blu-rays with 5.1 DTS-HD Master Audio or Dolby TrueHD? Do you leave it as it is, without any sound from the surround back speakers? Or do you upscale 5.1 to 7.1 using your A/V receiver? In your recommendation, what way should I treat the Blu-rays with 5.1?

A: The vast majority of movie soundtracks today are still mixed in 5.1 format, and likely will be for the foreseeable future. There are exceptions to this, of course. ('Toy Story 3' is notable as a native 7.1 mix.) However, by and large, anything more than 5.1 is rare.

Almost all Blu-rays that you'll find authored with discrete 7.1 soundtracks were remixed after-the-fact for home video. Sometimes, this is done with the filmmakers' participation and oversight, and other times it's a studio decision without the filmmakers' involvement.

As mentioned above, Dolby ProLogic IIx (or IIz) processing can be used to expand any 5.1 soundtrack to 7.1 configuration at home. In my experience, the results are very effective, and practically indistinguishable from a discrete 7.1 mix.

Among reviewers (and among home theater fans in general), there are two schools of thought for how to treat 5.1 soundtracks. On the one hand, some viewers prefer to listen to 5.1 soundtracks only in 5.1 format, and disable any extra processing. These people will set their receivers to only engage the center back channels if a soundtrack is encoded with discrete 7.1 audio. On the other hand, some listeners prefer to leave ProLogic IIx processing on at all times, and expand all 5.1 soundtracks to 7.1.

Personally, I fall in the latter camp. I leave ProLogic IIx on all the time. However, I can't tell you what you should do. This will ultimately come down to a matter of personal preference. My suggestion is to try leaving ProLogic IIx on and then watch a few movies with 5.1 soundtracks. If you don't like the results, you can always turn it off later.

TV Shows on Blu-ray

Q: I decided some time ago that I would never buy another DVD again, only Blu-ray. Like many, I enjoy certain TV shows. How can anyone know if a TV series that is already out on DVD will make it to Blu-ray? And I don't mean just digitally copied on a Blu-ray disc, but enhanced to high definition. I would love to own the whole 'Northern Exposure' series. It's only available on dvd, but they play high-def episodes on the Universal HD network.

A: I stopped trying to second guess which titles the studios will choose to issue on Blu-ray long ago. It's a much of a mystery to me as anyone. In some cases, I swear that the studio executives must just throw darts at a list of titles pinned to a wall. (Was 'Jimmy Hollywood' seriously just released on Blu-ray? Will a single human being on Earth choose to buy that disc? I can't imagine it. I doubt that even Christian Slater will want to own that one.)

Unfortunately, the presence of a particular title on HD broadcast is not a reliable indicator that the title will also be issued on Blu-ray. Studios might make money off syndication contracts, but still decide that a Blu-ray release wouldn't be profitable enough to attempt.

As for TV shows, I don't hold out much hope for older series like 'Northern Exposure'. The sad fact of the matter is that TV series on Blu-ray have sold poorly in general, even popular shows that are still on the air. Sony only released one season of 'Damages' on Blu-ray, and then gave up; later seasons are only available on DVD. Warner did the same for 'Nip/Tuck'. (Only the fourth of that show's seven seasons was released on Blu-ray.)

That's not to say that it's impossible. Studios do continue to trickle out the occasional TV title, including an older show now and again. HBO recently announced that a complete series box set for 'Deadwood will come out later this year. Still, I would generally only expect this for shows known to have large fan bases of collectors. It also helps if the series had a short run, which the studio can issue all at once.

'Northern Exposure' was a pretty popular show back in the day, but it hasn't really been in the public consciousness for a long time. And it ran for six seasons, which makes it a tricky proposition to start releasing now. (If the first season doesn't sell, there's little to no chance of the studio releasing more.)

But I don't claim to be psychic, and stranger things have happened. So, we really have no way of knowing for certain until the studio releases an official announcement one way or the other.

Homework Assignment: You Be the Advisor

The HD Advisor knows many things, but he doesn't know everything. Some questions are best answered with a consensus of opinions from our readers. If you can help to answer the following question, please post your response in our forum thread linked at the end of this article. Your advice and opinions matter too!

Macbook Pro HDMI Audio Problem

Q: I recently bought a 13" Macbook Pro (mid 2010). This is the model that supports HDMI audio and video output through a Mini-DisplayPort-to-HDMI cable. I connected it to my Marantz SR5003 A/V receiver, which outputs the video to my Samsung HDTV. I have no problems getting a video signal because it was instantaneously recognized. The Macbook Pro even configured itself to display at 1080p resolution on the HDTV. I also noticed right away that my receiver was displaying a 7.1 multi-channel PCM signal (similar to what you see when you plug in an original PS3). I then rented a movie from iTunes that included a 5.1 digital surround sound signal. That's where the problems started. The movie played and sounded fine in stereo mode. But when I switched over to the Surround Audio from the control bar, I got a stuttering noise coming out of my speakers. My receiver is still display a 7.1 multi-channel PCM signal at this point.

I searched the internet for some answers, and someone wrote in a forum to configure the Audio MIDI Setup from the Utilities folder. I promptly fired up the application, but whatever I do, I can't seem to get the audio to work. When I chose HDMI Output option, the inside options defaulted to 8ch-24bit. When I tried to change the option to Encoded Digital Audio, the stuttering disappeared, but there's still no sound. What was conspicuous was that now, my A/V receiver is displaying No Audio and the PCM display was flashing; meaning it wasn't receiving any signal. I know it cannot be a faulty cable because stereo worked just fine. I have also already gone into the Settings panel to choose HDMI as the output under the Sound setting. I looked through iTunes Preference menu, but there didn't seem to be any settings for audio. Could it be that the Marantz SR5003 A/V receiver cannot decode the signal for whatever reason? Is there something I'm not configuring right?

Check back soon for another round of answers. Keep those questions coming.

Joshua Zyber's opinions are his own and do not necessarily reflect those of this site, its owners or employees.

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