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There's Nyquist, there's the actual bandwidth limited range in relation with the actual microphones range and arguments for 192 helping reconstructing transients.

 

However there might be a better argument for using even more space disk : multichannel even for stereo. I'm convinced that what I discovered with MCH Electric Ladyland goes far beyond eventual differences in remastering talents or marketing strategies (Bernie Grundman signs the Stereo that is soso while Eddie Kramer signs the MCH ; the latter supervised the gorgeous Mono LP Axis signed by the former who delivers a soso Mono Mix in the recent SACD where the Stereo shines...).

 

Fact is MCH is more than 2.5 x heavier than the Stereo and I bet it's better use of space than 192 vs 96. Maybe it is also due to LFE and engineers daring to go deep low but MCH downfolded into Stereo via HQP offers aural sculptures of the bass line and of the kick drum that are really reminiscent of live gigs impressions. Even soundstage is deeper that what I'm accustomed to.

 

I'm thus starting a journey into MCH (to be played on my stereo) and suggestions and comments are welcome. As of Rock/Pop I start with https://www.quadraphonicquad.com/TabbedPollChart.htm

 

Edited on December the 5th : I have not experimented with Classical or Acoustic Jazz but dig that when MCH aims at recreating natural acoustics, reverb, etc, down mixing to Stereo is a non sense. However, when reproducing (better, those who know say) the natural acoustics of the concert hall  etc is not the goal, ie with Talking Heads, Steely Dan or Bjork, MCH to Stereo offers better bass delineation, smoother and more natural vocals and more noticeable soundstage vs the standard Stereo. 

 

Edited by Le Concombre Masqué

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32 minutes ago, Le Concombre Masqué said:

There's Nyquist, there's the actual bandwidth limited range in relation with the actual microphones range and arguments for 192 helping reconstructing transients.

 

However there might be a better argument for using even more space disk : multichannel even for stereo. I'm convinced that what I discovered with MCH Electric Ladyland goes far beyond eventual differences in remastering talents or marketing strategies (Bernie Grundman signs the Stereo that is soso while Eddie Kramer signs the MCH ; the latter supervised the gorgeous Mono LP Axis signed by the former who delivers a soso Mono Mix in the recent SACD where the Stereo shines...).

 

Fact is MCH is more than 2.5 x heavier than the Stereo and I bet it's better use of space than 192 vs 96. Maybe it is also due to LFE and engineers daring to go deep low but MCH downfolded into Stereo via HQP offers aural sculptures of the bass line and of the kick drum that are really reminiscent of live gigs impressions. Even soundstage is deeper that what I'm accustomed to.

 

I'm thus starting a journey into MCH (to be played on my stereo) and suggestions and comments are welcome. As of Rock/Pop I start with https://www.quadraphonicquad.com/TabbedPollChart.htm

 

 

Never thought of trying this. So how do you downmix from MCH to 2 channels in HQP? What proportions and what channels mixed into left/right? Are you doing any convolution on these? And is this over speakers or headphones?

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46 minutes ago, pkane2001 said:

 

Never thought of trying this. So how do you downmix from MCH to 2 channels in HQP? What proportions and what channels mixed into left/right? Are you doing any convolution on these? And is this over speakers or headphones?

Neither did I till I was disappointed by Stereo EL and motivated (I own original Barclay, Track, Reprise LPs...) to hear it better. All answers are a few posts above the last one in the HQP thread and summarised in this picture : convolution, yes ; applied to each channeI (cpu heavy ; ie I don't have the horse power to do it with sacd to dsf rips)  + this is over speakers IMG_8324 (1).jpg

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1 hour ago, Le Concombre Masqué said:

Fact is MCH is more than 2.5 x heavier than the Stereo and I bet it's better use of space than 192 vs 96. Maybe it is also due to LFE and engineers daring to go deep low but MCH downfolded into Stereo via HQP offers aural sculptures of the bass line and of the kick drum that are really reminiscent of live gigs impressions. Even soundstage is deeper that what I'm accustomed to.

Especially if you play it in multichannel.😉 

To be frank, my experience with down-mixing good multichannel to stereo has been consistently disappointing.

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53 minutes ago, Le Concombre Masqué said:

All answers are a few posts above the last one in the HQP thread and summarised in this picture : convolution, yes ; applied to each channeI (cpu heavy ; ie I don't have the horse power to do it with sacd to dsf rips)  + this is over speakers 

How did you arrive at these settings?  Is there any reason to believe that they are generally applicable given that the original multichannel mixes vary so greatly in their balance/distribution? 

Edit:  @Miska

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16 minutes ago, Kal Rubinson said:

How did you arrive at these settings?  Is there any reason to believe that they are generally applicable given that the original multichannel mixes vary so greatly in their balance/distribution?

Those settings were kindly indicated by Miska.

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4 hours ago, Kal Rubinson said:

OK but the questions are still valid.  

 

Are there different standards for various recording formats, or is it up to the individual doing the recording as to how the channels are balanced in MCH? I would suspect that the downmixing factors would depend more on the speaker layout rather than whatever balance is chosen in recording/mastering. 

 

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36 minutes ago, pkane2001 said:

 

Are there different standards for various recording formats, or is it up to the individual doing the recording as to how the channels are balanced in MCH?

How much goes into each channel and how loud it is relative to the others is, for music, determined by the individuals who mix and master each recording.  AFAIK, there is no standard because it is an "artistic" element.  Recordings range from those with an almost inaudible surround to those where the the surround channels are louder than the front.  There are, also, recordings where the soloist is exclusively in the center channel, those where he/she is centered but recorded into L/C/R and a few in which the soloist is stereo mike-d and does not appear in the center channel at all.  Add to that the presence, absence and variable level of the LFE.  That's off the top of my head and I know there are other strange possibilities.  How can one think that there will be a standard for the mix-down?

 

42 minutes ago, pkane2001 said:

I would suspect that the downmixing factors would depend more on the speaker layout rather than whatever balance is chosen in recording/mastering. 

Speaker layout is somewhat standardized, fwiw.

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42 minutes ago, pkane2001 said:

Are there different standards for various recording formats, or is it up to the individual doing the recording as to how the channels are balanced in MCH? I would suspect that the downmixing factors would depend more on the speaker layout rather than whatever balance is chosen in recording/mastering.

The Dolby spec includes rules for downmixing as well as preferred speaker placement.

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25 minutes ago, Kal Rubinson said:

 How can one think that there will be a standard for the mix-down?

 

Speaker layout is somewhat standardized, fwiw.

 

Here's my thinking. If all the channels are recorded at the same level, I will get a contribution from each speaker that is inversely proportional to the square of speaker distance from the ear, and with a corresponding delay.  While source recording levels can vary widely for each channel, the relative contribution of each channel to each of my ears remains constant, and that's what I think would define the downmix proportion of that channel. Therefore, the downmix proportion is related to the speaker layout/distance. Am I wrong?

 

 

 

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24 minutes ago, mansr said:

The Dolby spec includes rules for downmixing as well as preferred speaker placement.

 

That would make sense as these, I believe, are related.

 

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My Lexicon MC12 processor offers the possibility to downmix 5.1 to 2 channels.

The only thing the processor knows is the distance from each speaker to my listening position, based on microphone assisted measurements.

It does not take into account how the music has been recorded.

So, can one not assume there is kind of a generic (standardised ?) way to downmix?

 

 

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1 hour ago, mansr said:

The Dolby spec includes rules for downmixing as well as preferred speaker placement.

AFAIK, Dolby has little to do with music recordings.  So, I would not assume that the mix-down rules apply.  As for speaker placement, they define it (per ITU-R BS.2159-6) in terms of angle but not distance. 

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43 minutes ago, pkane2001 said:

Here's my thinking. If all the channels are recorded at the same level.................

I would not assume that.

 

44 minutes ago, pkane2001 said:

I will get a contribution from each speaker that is inversely proportional to the square of speaker distance from the ear, and with a corresponding delay. 

Where is there a distance spec except for the presumption that it is equal for each speaker.  If so, no computation is needed.

 

I am not saying that you cannot/should not do what you intend but I question whether any presumptions about how to do it are universally applicable.  Sure, I have several devices that will to MCH-to-stereo mixdown, some with control of the parameters, but the results rarely satisfy me, compared to the native stereo tracks. 

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4 minutes ago, Kal Rubinson said:

AFAIK, Dolby has little to do with music recordings. So, I would not assume that the mix-down rules apply.

Other systems may of course have other mixdown rules. Even Dolby allows overriding the defaults in the stream headers. My point was that rules exist. Of course, you're still free to use whatever ratios you think sound best.

 

4 minutes ago, Kal Rubinson said:

  As for speaker placement, they define it (per ITU-R BS.2159-6) in terms of angle but not distance. 

Right. A calibrated setup will compensate for speaker distance using per-channel delay and gain adjustments.

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10 minutes ago, mansr said:

Right. A calibrated setup will compensate for speaker distance using per-channel delay and gain adjustments.

True.  However, the proposition being discussed is a protocol for down-mixing from multichannel to stereo.  So, if the recording was produced with the assumption that the speakers will be equidistant, the down-mix then need not compensate for any difference in distance among the channel.s

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Dolby has mixdown rules encoded in recording through the metadata which will be applied by the decoder. 

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Just now, STC said:

Dolby has mixdown rules encoded in recording through the metadata which will be applied by the decoder. 

How many Dolby music recordings do you have?  I have none. 

 

(A quick check on my server shows only aif, dff, dsf, flac, and wav.  A number were originally dts-MA but are now flac or wav.)

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8 minutes ago, Kal Rubinson said:

How many Dolby music recordings do you have?  I have none.

There used to be CDs with DTS encoded surround sound. I'm not sure if there ever were any using Dolby though. The concept was never very popular.

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16 minutes ago, mansr said:

There used to be CDs with DTS encoded surround sound. I'm not sure if there ever were any using Dolby though. The concept was never very popular.

Yes, there were some in Dolby, too, but they were very few.  Telarc and Delos come to mind.  Most of the music discs with Dolby or dts would have been DVDs and its variants.

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36 minutes ago, Kal Rubinson said:

True.  However, the proposition being discussed is a protocol for down-mixing from multichannel to stereo.  So, if the recording was produced with the assumption that the speakers will be equidistant, the down-mix then need not compensate for any difference in distance among the channel.s

 

Except possibly for the center channel, if used, that should be split equally between left and right, so its contribution will be less than 1.0 factor during downmixing. And maybe LFE channel, as well?

 

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1 minute ago, pkane2001 said:

Except possibly for the center channel, if used, that should be split equally between left and right, so its contribution will be less than 1.0 factor during downmixing.

But that would be a function of how that center channel was mixed. 

 

Anyway, since there is such wide ranging variations in how the 6 channels are recorded, mixed and mastered in order to achieve wildly different effects, I think you can do whatever you think works for you.  Personally, I do not think that combining any two output channels at any proportion is likely to be a good thing for any instruments/voice that span those channels.

 

Disclaimer:  I am only interested in multichannel discs discretely recorded/mastered live in real time (in studio or in performance) and not synthesized from separate events or, for the most part, from multitrack originals made prior to considerations of multichannel release.

 

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5 minutes ago, Kal Rubinson said:

Personally, I do not think that combining any two output channels at any proportion is likely to be a good thing for any instruments/voice that span those channels.

 

Most likely. I don't have an opinion having never tried this. It would seem that any benefit to downmixing from MCH to 2 channel compared to a straight 2 channel recording would be in mastering. Any multi-miked recording is by definition MCH, and is downmixed by a mastering engineer. By downmixing at home I might gain a bit of a control over the process, but personally I don't want the extra work. I'd rather an experienced professional do this for me :)

 

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51 minutes ago, Kal Rubinson said:

How many Dolby music recordings do you have?  I have none. 

 

(A quick check on my server shows only aif, dff, dsf, flac, and wav.  A number were originally dts-MA but are now flac or wav.)

 

I was stunned for a while with the question before realizing that almost 99.99% of my fav are from cinema soundtrack meant to be played with Dolby. Even a simple song will have have an orchestra music incorporated in them. They are made for multichannel playback and often incorporate higher technology such as Auro.

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