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Topic: Stereo CDs, Boxed CDs and Pro Logic II decoder, (I'm a bit... confused)< Next Oldest | Next Newest >
Ugo Offline




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Posted: April 12 2005, 08:19

This is pointed specifically at Korgscrew. I don't know whether maybe it ought to be a PM. Korgscrew, if you think it ought to, just PM me and delete the topic. ;)

In more than one occasion, you said that the TB, HR and Ommadawn mixes on the Boxed CDs are quadrophonic (in spite of the booklet saying they're stereo) and that a Pro Logic II decoder reads/decodes them quite well. But when you recently said that the decoder produces the same effect on any stereo CD, this got me a bit perplexed. While listening to Ommadawn, for example, in some points I hear some instruments (especially the guitar) literally spinning around me. [The spinning direction I get is clockwise, starting (I think) from the front-left speaker.] And on the TB Part 1 Finale I hear each instrument occupying its very own place and not moving from there. Is all this supposed to happen on an ordinary stereo mix through a Pro Logic II decoder? Or does it happen because the Boxed mixes are really quad and they do actually work very well on my decoder? :)

P.S.: Of course the player or the amplifier do not say anything about the Boxed CDs being quad. They show them as being L/R stereo. :)


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Ugo C. - a devoted Amarokian
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Posted: April 12 2005, 09:12

A Pro Logic II decoder will produce rear channel information out of just about any old stereo CD, just as an SQ or QS decoder will. I never said it was the same effect as when they're properly encoded, though (however, playing matrix encoded material through the wrong decoding matrix can result in similarly random results). Pro Logic II is in fact designed to be good at synthesising surround information from stereo (I hear it's not too dissimilar to QS, decoders of which were also quite well thought of for their surround synthesis abilities. Pro Logic is very different to QS though, so this may just be hearsay. I've never seen anything detailing how the Pro Logic II process actually works).

The Boxed CDs are really quad, as is Exposed and the ordinary release of Hergest Ridge. I've played them quite often through a genuine SQ decoder and can verify that not only are they the same as the LPs, but that Tubular Bells produces the same results (roughly speaking - we're comparing Kumquats with Pomelos here) as the SACD.

Spinning effects are very unlikely to be had from a stereo CD. I'd always take that as a sign of a deliberately produced surround mix. There are a couple spinning solos on Ommadawn, and a tambourine goes round at one point too.
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Posted: April 12 2005, 09:44

Quote (Korgscrew @ April 12 2005, 15:12)
There are a couple spinning solos on Ommadawn, and a tambourine goes round at one point too.

Yes. And during the 'drunk' version of The Sailor's Hornpipe, Viv Stanshall's voice stands almost constantly in the middle, while everything else moves around. Also, when the proper Hornpipe starts, you get a very good separation on all of the four channels (front-left, front-right, rear-left, rear-right).

Anyway, thanks very, very much for your reply. When I talked about Pro Logic II producing 'the same effect', I was just referring to the separation of channels. I wasn't talking about quad mixes in particular - it was wrongly phrased. :) My decoder also produces fine surround effects on some other CDs and videotapes I have, marked "Dolby Surround" on the boxes. ;)

I've heard that the (new) Apocalypse Now soundtrack CD is also mixed in quad. Is this true? I still have to try it. :)


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Korgscrew Offline




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Posted: April 12 2005, 10:13

Viv's voice is, oddly, more left-centre (that is, equally spread between front and rear left) when reproduced properly. It's very difficult to locate him as being there, as things placed in that position don't image in the same way as things placed between front left and right, or indeed rear left and right (there's also some of him in the right channels, just not as much). I think putting him in the middle would have made more sense, really.

I'd be disappointed if your Dolby decoder didn't decode Dolby Surround, as that's what it's meant to do ;)
It should produce interesting effects on a variety of ordinary stereo CDs though (or any stereo sources you care to feed through it).

Don't know about the Apocalypse Now CD, but it happens. The soundtrack from the film version of Tommy is encoded in QS, as that's what they used to produce the film's original 'quintaphonic' sound (a four channel QS mix with an added hard centre) - they transferred that mix direct to disc (originally LP of course), and the resulting album is an unmarked QS release. Apocalypse Now was released with a Dolby Soundtrack, and I can't really see why the music would have been quad encoded at any point (especially in 1979 when quad was firmly on its way out - it's a bit of a mystery why they bothered with Exposed actually, considering that they'd given up on doing Incantations in quad, feeling that the concept was commercially dead), but if it was encoded with a matrix quad system when it was mixed back then, it'll still be in that format now. If it's been remixed since then, it won't be.
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Posted: April 12 2005, 11:02

Quote (Korgscrew @ April 12 2005, 16:13)
Apocalypse Now was released with a Dolby Soundtrack, and I can't really see why the music would have been quad encoded at any point (especially in 1979 when quad was firmly on its way out - it's a bit of a mystery why they bothered with Exposed actually, considering that they'd given up on doing Incantations in quad, feeling that the concept was commercially dead), but if it was encoded with a matrix quad system when it was mixed back then, it'll still be in that format now. If it's been remixed since then, it won't be.

Going off topic again... sorry... :)

This is what F.F. Coppola [no relation :D] writes in the AN soundtrack's CD booklet: "All this [meaning the whole movie soundtrack, including the music] was shaped into quadraphonic sound. I remember how much I wanted to demonstrate the power of discrete [discreet?] quadraphonic sound, I invited many of my friends, amongst them Walter Murch [AN's sound engineer] and George Lucas, I turned off the lights and they sat in darkness listening to the effect of space and vitality that the quadraphonic experience had. This was the birth of Dolby Split-Surround Sound (now known as the 5.1 format), which was developed by Walter Murch and first used on APOCALYPSE NOW".
He also says that a remix was done on the new release (which includes two unreleased tracks) to remove the bits of dialogue that were featured in the original release, but the music itself was not remixed - it was just remastered.

The DVD release of the movie (Apocalypse Now Redux) features a DTS 5.1 soundtrack, which IMHO is great. :)


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