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This is an old revision of this page, as edited by HairyWombat (talk | contribs) at 17:44, 19 May 2009 (→Merging with Matrix (sound recording): Response). The present address (URL) is a permanent link to this revision, which may differ significantly from the current revision.

Question

does matrix decoding involve utilizing 2 stereo channels being "mirrored" and separating offsets on the other channels? (unsigned comment from anon) —Preceding unsigned comment added by 69.209.157.150 (talk) 13:41, 4 Febuary 2006 (UTC)

No. For example, UHJ decoding produces W, X, Y channels from Left, Right. Martin.leese 22:33, 6 January 2007 (UTC)[reply]

Merging with Matrix (sound recording)

The two pages are complementary in that one should describe encoding and the other decoding. (Although that doesn't seem to be the way they have been written.) I don't have strong views on merging, but feel strongly that the merged article, if there be one, should retain the "2:4" notation used in Matrix decoder. Martin.leese 07:52, 7 January 2007 (UTC)[reply]

I am of the opinion that there should be two pages, namely 'audio matrix decoding' (not 'decoder') and 'audio matrix encoding', each of which should have proper links to the other. References to applications for the technology (such as sound recording) should appear on the page(s). Note that pages already exist for encoder and decoder. Novatek 19:56, 20 March 2007 (UTC)[reply]
HairyWombat, you undid my addition of SQ Matrix Encoding, which, in hindsight, I agree with - we should either split the topics out into matrix encoding and decoding or just do a general 'surround matrixing' topic with separate sections on the complete encoding/decoding equations for individual systems. Ty Chamberlain (talk) 13:31, 18 May 2009 (UTC)[reply]

If you had changed all the headings then I would not have undone. As for what to do with this article, please see my comments under #Why_ENcoding_matricies_in_Matrix_DEcoder.3F below. Note that when I wrote this, the SQ section was as uninformative as the rest. Why don't you carve out SQ into its own article (called Stereo quadraphonic) and delete Matrix decoder? HairyWombat (talk) 15:49, 18 May 2009 (UTC)[reply]

Ah, OK, gotcha - thanks for telling me "why" - I'll remember that in the future. I'm working on, but haven't posted yet, an in-depth article on Lynn Olson's (never produced) advanced Shadow Vector SQ Decoder, so I'll start working on SQ too so it can be a really complete source of info on the SQ system -encoding/decoding/history/development, etc... - there is SO MUCH incorrect info on the net about SQ (and quad/surround history in general) - some of it from people who were 'there' at the time and should know better. BTW, HairyWombat, how much do you know about quad/surround history and formats? I ask because your additions/deletions about the Ghent microphone made me dig deeper and (initially thinking you were wrong) I found that you were 100% correct - development of the SoundField and Ghent is quite "obscure" really, from a standard quadraphiles knowledge, so I've been really impressed. —Preceding unsigned comment added by Disclord (talk • contribs) 17:24, 18 May 2009 (UTC)[reply]

Although I was around in the early 1970s, and was interested in the various quad systems, I have no special knowledge of them. I did not purchase one, making do with a Hafler Circuit until the format war had been resolved. (Smart move on my part.) I do know Ambisonics (which is not a quad system); I created and maintain the FAQ on this. Hence, I know well the development history of the Soundfield mic, and knew it was entirely separate from SQ. However, I did not buy an Ambisonic decoder until 1994. The detail of the Gwent mic I had to research to edit your contribution on it. I was never a fan of SQ; its locus on the Scheiber Sphere was too twisted. Note that Ambisonics, unlike SQ, is alive and well with over 200 contemporary pieces available for free download at Ambsionia.com.

If you get your SQ article up and running then I will insert a link to it at Quadraphonic sound#SQ / Stereo Quadraphonic using {{Main}}. At that time, I will also trim further the SQ section. People keep trying to expand it and I keep trimming it because the article is not about SQ, so the SQ section needs to be about the same length as the other sections. A separate SQ article will give such people more freedom. By the way, don't forget to always sign contributions to Talk pages using ~~~~, like this HairyWombat (talk) 23:59, 18 May 2009 (UTC)[reply]

I guess I had a 'brain fart' yesterday because I thought I did sign my 'talk' contribution using the four tildes - of course, I was up all night before that with flu, so it probably affected my memory... I have a truly beautiful sounding Ambisonic G-Format DTS CD (a Jeff Silberman Soundfield recording done for DTS in 1996), but for the life of me, I've never understood the attraction of the 2-channel UHJ "BHJ" format - in either undecoded 2 channel or fully decoded playback, I find UHJ to be completely unlistenable - to me, decoded UHJ is as bad as non-logic SQ in terms of phasiness and lack of localization - and the CF phase error makes it even worse than non-logic SQ. This is all completely personal opinion, of course, but I'm very familiar with all the psychoacoustic advantages of the Ambisonic 2-channel format (and have read the various Gerzon, Sommerwerck, Leese, Fellget - and others - Ambisonic UHJ papers) but I've never found the 2-channel format to 'work' in real-life - now, in the 'discrete' B-Format/G-Format, Ambisonics works very well and is stunning - but UHJ, forget it. Please don't take that as an attack on you - UHJ advocates can be very rabid in their defense of the format. I wish some company had produced a variable-preference UHJ decoder - I believe the BBC strongly advocated for their use, but none of the UHJ patent owners ever bothered to produce one. I apologize for asking about your quad knowledge - I didn't realize who you were until you mentioned the Ambisonic FAQ, which I've read many, many times. Where in the world does the name "HairyWombat" come from? "Disclord" comes from the name of a VHD Video Disc player I got from Japan - the VHD format was never released in the USA and Panasonic called their VHD players "Disclord" - JVC called theirs "DiscWorld." Maybe I should have kept my 'old' AOL screen name of "Stereoboy" for Wikipedia? They (Wikipedia) need to add a user preference to automatically sign all "talk" contributions. Ty Chamberlain (talk) 14:39, 19 May 2009 (UTC)[reply]

UHJ was optimised for the average listener using the results on perception of phaseyness carried out by the BBC. Unfortunately, nobody is average so the results vary. There were plans for a "logic" UHJ decoder in the 1970s, but Ambisonics died before it could be brought to fruition. These days, given multi-channel DVDs, nobody is interested in developments for UHJ. "HairyWombat" came about because I used to work in satellite image processing. Somebody published a paper on the detection of hairy-nosed wombats from space, and the name stuck in my mind. HairyWombat (talk) 17:44, 19 May 2009 (UTC)[reply]

See also Discretedored?

Is Discretedored even a word? I did a google search and the only page it returns is this wiki entry, not even one other suggestion. Possible mistype of some form of audio encoding or strange vandalism? —Preceding unsigned comment added by 69.241.82.132 (talk) 09:19, 4 January 2008 (UTC)[reply]

Dolby Surround and Pro Logic should be the same

The Dolby Surround matrix and the Dolby Pro Logic matrix should be the same. I don't recall which of the two presented is the correct one, and so cannot fix the article. But they should definately be the same matrix; one of them is definately wrong. HairyWombat (talk) 13:50, 17 April 2009 (UTC)[reply]

I think the second set of equations is correct (i.e. sqrt(1/2)). Dolby Laboratories received US Patent 5,291,557 (http://www.google.com/patents?vid=USPAT5291557), which has this equation in claim 6. —Preceding unsigned comment added by Beavioso (talk • contribs) 23:05, 12 May 2009 (UTC)[reply]

Yes, the encoding for both Dolby Surround and Dolby Pro-Logic is exactly the same - both use the "Dolby MP" Matrix for surround encoding. Dolby MP employs the same matrix encoding equations as Peter Scheiber's original matrix patent that started the "matrix quad wars" (US Patent #3,632,886). While Dolby MP was developed independently of Scheiber's matrix, they later paid royalties to him which stopped when the patents expired (Scheiber now collects no royalties from Dolby). Dolby MP is a pure amplitude matrix using anti-polarity signals to encode the surround channel (with no phase encoding used), unlike, say, CBS SQ which is a true phase matrix and has accurate encoding/decoding only over the bandwidth and precision of its 90 degree phase shifts. Dolby Pro-Logic II encoding is also a pure amplitude matrix that uses anti-polarity encoding and slight level differences to encode the Lb and Rb channels (Circle Surround uses basically the same surround encoding technique as PL-II, as does Lexicon Logic-7) - again, no phase encoding being used. Both Dolby MP and PL-II are "Great Circle" encoding systems on the Scheiber Sphere (Energy Sphere). (apparently, no one has done an entry for the Scheiber Sphere on Wikipedia yet) —Preceding Ty Chamberlain (talk) 19:37, 17 May 2009 (UTC) • contribs) 19:16, 17 May 2009 (UTC) [reply]

Why ENcoding matricies in Matrix DEcoder?

This article is titled Matrix DEcoder, and yet it contains little except the ENcoding matricies for the various schemes. Surely it should contain the DEcoding matricies. I have no desire to correct this; if I had my way the whole article would be deleted as it contains only information better expressed elsewhere, and I do not see what purpose it serves. HairyWombat (talk) 19:23, 20 April 2009 (UTC)[reply]

Should be an article on advanced decoding

There should be an article on Wikipedia on advanced matrix surround decoding, such as Variable De-matrixing (Sansui QS Vario-Matrix, SQ Shadow Vector), Matrix Multiplication/Vector Cancellation (Tate DES for SQ, CBS Paramatrix for SQ, Scheiber-Sonics 360 Spatial Decoder for SQ, Dolby Pro-Logic & PL-II), Gain-Riding Logic (CBS SQ Full-Wavematching Logic, Circle Surround, Peter Scheiber's 1970's quad patents), plus the various methods of detecting channel dominance and directionality, (such as Axis-Crossings, wavematching, envelope comparison, etc...) I've been talking with Lynn Olson, the inventor of the Shadow Vector Signal Analysis Unit for SQ decoding (US Patent #4,018,992) and while it never reached the market because Audionics set its development aside to work on the Tate DES, I think Wikipedia would be the perfect place for info on it and other advanced forms of matrix surround decoding. Hopefully, we could get the inventors such as Lynn Olson or Martin Willcocks (inventor of the Tate DES) to add info. Or Jim Fosgate, since he's the inventor of Dolby Pro-Logic II as well as the designer of the vast majority of award winning matrix decoders, such as the legendary Fosgate 101A Tate II Surround Stereo SQ Decoder - it was also the first advanced cancellation decoder to incorporate a high-separation Cinema mode for Dolby Stereo encoded films. (Dolby theater decoders at the time were based on the Tate II DES chip that the 101A used) Ty Chamberlain (talk) 19:37, 17 May 2009 (UTC) —Preceding unsigned comment added by Disclord (talk • contribs) 19:34, 17 May 2009 (UTC)[reply]

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