Fitzcaraldo215
Major Contributor
- Joined
- Mar 4, 2016
- Messages
- 1,440
- Likes
- 640
In the Genelec on Audio Science thread, it was suggested that a new thread be opened to discuss multichannel (Mch). Many aspects of Mch seem perplexing and mysterious to a lot of audiophiles, although Mch audio has been around for decades. But, not too much of interest happened with it commercially in music until about 15 years ago when Mch SACDs started to appear.
So, here is a summary and outline of some things I have absorbed in 10 years as a dedicated multichannel music listener and collector. I will not attempt to justify everything. The underlying facts or detailed reasoning can be independently checked by those interested. I hope this is helpful.
I will emphasize a basic 5.1 Mch music system which can also used for video material. I do not recommend 7.1. It is similar, but there are more possible variations in angular setup, hence less standardization, and I do not find it offers a great deal more than 5.1. Most 7.1 is on video BDs, not on most music, and the total number of 7.1 disc releases has been disappointing. Immersive 3D, while interesting, is still way too complicated for me, and its commercial survival is not guaranteed at this point, so I will not touch on it. But, 3D additively builds on the same basic 5/7.1 architecture. It is still an early stage technology worth following.
Most Mch music today is on 5.0/.1 SACD, period. BD-Audio is much less common and much less significant. Mch downloads are also increasingly becoming available, normally just replicating the discs. Older attempts on DVD, HD DVD, etc. are few and don't really interest me that much. Most BD Videos are also compatible with 5.1 Mch, as are many earlier DVDs.
This excellent site, which has been my Bible in building my music collection, lists virtually all Mch music releases on SACD and BD-A:
https://www.hraudio.net/
Note that many releases may now be OOP. Note also that new releases still continue to appear. It is a niche, but not a dead one.
The prevailing mixing/mastering standard on most all 5.0/.1 music recordings is based on ITU-R BS.775-1. There may be a few insignificant exceptions, such as 4.0 recordings, Quad-era remasters, and '50's 3-channel recordings, but they also work just fine with the ITU standard. Here is Genelec's description of that ITU standard for monitoring plus related matters for setup by recording/mastering professionals:
https://www.genelec.com/documents/publications/PlacementandRoomAcousticsInteraction.pdf
The ITU Mch standard can be summarized as requiring 5 identical, equidistant, monopole speakers at 0, +-30 and +-110 degrees relative to front dead center from the Main Listening Position. Subwoofers are optional, and I do recommend them. All channels are level trimmed for equal volume on reference level test tones at the Main Listening Position.
Note that mic placement and recording techniques, minimalist 5.0 vs larger multi mic arrays, etc. are of secondary importance as long as the final mix and mastering are done according to the same consistent standard, which is overwhelmingly the case. That, and recording engineers do not like to share too many details of their "art". Listeners might favor one engineering approach over others. But, the same final mastering and playback standard prevails, fortunately.
However, we can successfully "cheat" on the ITU standard in a number of ways in home playback setup and still achieve success, as follows:
--nonidentical speakers might work satisfactorily, if they are reasonably timbre matched, as from the same mfr. Smaller surround speakers need not be a problem with adequate matching, particularly with subs offloading the bass. A horizontal center channel, very useful with a video display and properly matched, can also work surprisingly well. Do not underestimate the importance of the center channel, even with just music.
--full range DSP EQ might be of great help to voice all channels near identically at the sweet spot via the same target curve.
--DSP distance (time) compensation and channel level trims in most all digital Mch AVR's and prepros can transparently fix level and distance inequalities between channels, totally alleviating a major potential setup issue.
--I use electrostat dipoles frontally aimed at the MLP, and they work quite well in comparison to all-monopole setups I have heard. A recording engineer friend uses 5 humongous Sound Labs electrostats.
The system calibration, usually via a simply automated setup process using a supplied mic and generated test tones with most Mch processors, sets distance, channel level trims, possibly subwoofer xovers, and it may also simultaneously calibrate an onboard DSP EQ tool for "room EQ".
In simple summary, that is about it. But, easier said than done.
Here are some caveats:
-- Obviously, you need a source(s). Universal CD/SACD/DVD/BD players will output Mch from SACD digitally only via HDMI to the processor. I personally use USB from a PC into a Mch DAC, and all DSP is done in my PC by JRiver and Dirac Live software. But, mine is an esoteric approach.
--DSD from SACDs or downloads must be converted to PCM either by the player or by the processor in order to use any DSP features - speaker distance correction, bass management, room EQ, etc. This can be done "on the fly" in real time from DSD discs or files, which is how I do it.
--DSD from SACD, with some effort, is also now able to be ripped to hard drive for computer playback using certain specific PS3, Oppo, Pioneer, Sony, Cambridge, etc. players plus hacking software. Mch Flac, etc. downloads are increasingly available, usually from the label's site. BD-As can also be ripped, but require extra effort to segment the BD chapters into tracks. BD Videos in Mch are also easily ripped, but they are necessarily huge in size.
-- Analog Mch preamps and analog interconnections are not recommended for Mch, although analog is what goes to the amps and speakers. There are only a few such choices, and they are lacking in features like DSP, and too limiting. There is no possibility of speaker distance/time correction in a Mch analog preamp, and they often lack bass management. However, some purists prefer an identical, equidistant speaker setup and analog Mch preamp for direct DSD to analog playback. It is not worth it in my view.
-- A single master volume control is a necessity. Don't believe you can achieve success cobbling together several old stereo integrated amps or preamp/amps. Each time you adjust overall volume on the several resulting volume controls, you are messing up the interchannel level calibration, which is very important to maintain.
-- What about video? If you look at the speaker layout standards, which are also the mastering standards, for 5.1 Dolby True HD and DTS HD Master Audio, you will find them completely congruent with the ITU standard described here. Mch with video works quite well for me on my music-oriented system.
I will recommend a number of SACD labels I have found to consistently deliver high quality, discrete Mch music newly recorded over the past 15 years or so, as follows:
--BIS
--Channel Classics
--PentaTone
--RCO Live
--Reference Recordings
--Telarc (defunct)
--Harmonia Mundi
--Chandos
--2L, many also on BD-A
--Linn
--many other small European labels, though LSO Live I find sonically mediocre
Also, major labels like DG and RCA have released some good ones, but many fewer than any of the above.
The good or bad news, depending on your viewpoint, is that it is mostly all classical. The Mch Dark Side of the Moon remastering is initially striking, and probably the largest selling Mch SACD ever, but it is a simple repanned "surround sound" mix from the multitrack originals. I don't think it successfully illustrates what Mch can really do, a familiar story with Mch rock, unfortunately. I do very much like the Allman Bros. Live at the Filmore East and Eat a Peach, remastered from Mch Quad era originals from live concerts. I have not found much jazz or other genres that are really good Mch, but I have not searched and listened that extensively for them.
I have built my library around discrete Mch music recordings. Is upmixing from stereo sources to Mch nearly as good? It can be good and preferable to stereo, but, frankly, it does not come that close to discrete Mch in my experience, and it will not reveal how good Mch can really be. I do not listen to much from stereo on my main system, and I prefer to leave that in stereo rather than upmix it.
So, here is a summary and outline of some things I have absorbed in 10 years as a dedicated multichannel music listener and collector. I will not attempt to justify everything. The underlying facts or detailed reasoning can be independently checked by those interested. I hope this is helpful.
I will emphasize a basic 5.1 Mch music system which can also used for video material. I do not recommend 7.1. It is similar, but there are more possible variations in angular setup, hence less standardization, and I do not find it offers a great deal more than 5.1. Most 7.1 is on video BDs, not on most music, and the total number of 7.1 disc releases has been disappointing. Immersive 3D, while interesting, is still way too complicated for me, and its commercial survival is not guaranteed at this point, so I will not touch on it. But, 3D additively builds on the same basic 5/7.1 architecture. It is still an early stage technology worth following.
Most Mch music today is on 5.0/.1 SACD, period. BD-Audio is much less common and much less significant. Mch downloads are also increasingly becoming available, normally just replicating the discs. Older attempts on DVD, HD DVD, etc. are few and don't really interest me that much. Most BD Videos are also compatible with 5.1 Mch, as are many earlier DVDs.
This excellent site, which has been my Bible in building my music collection, lists virtually all Mch music releases on SACD and BD-A:
https://www.hraudio.net/
Note that many releases may now be OOP. Note also that new releases still continue to appear. It is a niche, but not a dead one.
The prevailing mixing/mastering standard on most all 5.0/.1 music recordings is based on ITU-R BS.775-1. There may be a few insignificant exceptions, such as 4.0 recordings, Quad-era remasters, and '50's 3-channel recordings, but they also work just fine with the ITU standard. Here is Genelec's description of that ITU standard for monitoring plus related matters for setup by recording/mastering professionals:
https://www.genelec.com/documents/publications/PlacementandRoomAcousticsInteraction.pdf
The ITU Mch standard can be summarized as requiring 5 identical, equidistant, monopole speakers at 0, +-30 and +-110 degrees relative to front dead center from the Main Listening Position. Subwoofers are optional, and I do recommend them. All channels are level trimmed for equal volume on reference level test tones at the Main Listening Position.
Note that mic placement and recording techniques, minimalist 5.0 vs larger multi mic arrays, etc. are of secondary importance as long as the final mix and mastering are done according to the same consistent standard, which is overwhelmingly the case. That, and recording engineers do not like to share too many details of their "art". Listeners might favor one engineering approach over others. But, the same final mastering and playback standard prevails, fortunately.
However, we can successfully "cheat" on the ITU standard in a number of ways in home playback setup and still achieve success, as follows:
--nonidentical speakers might work satisfactorily, if they are reasonably timbre matched, as from the same mfr. Smaller surround speakers need not be a problem with adequate matching, particularly with subs offloading the bass. A horizontal center channel, very useful with a video display and properly matched, can also work surprisingly well. Do not underestimate the importance of the center channel, even with just music.
--full range DSP EQ might be of great help to voice all channels near identically at the sweet spot via the same target curve.
--DSP distance (time) compensation and channel level trims in most all digital Mch AVR's and prepros can transparently fix level and distance inequalities between channels, totally alleviating a major potential setup issue.
--I use electrostat dipoles frontally aimed at the MLP, and they work quite well in comparison to all-monopole setups I have heard. A recording engineer friend uses 5 humongous Sound Labs electrostats.
The system calibration, usually via a simply automated setup process using a supplied mic and generated test tones with most Mch processors, sets distance, channel level trims, possibly subwoofer xovers, and it may also simultaneously calibrate an onboard DSP EQ tool for "room EQ".
In simple summary, that is about it. But, easier said than done.
Here are some caveats:
-- Obviously, you need a source(s). Universal CD/SACD/DVD/BD players will output Mch from SACD digitally only via HDMI to the processor. I personally use USB from a PC into a Mch DAC, and all DSP is done in my PC by JRiver and Dirac Live software. But, mine is an esoteric approach.
--DSD from SACDs or downloads must be converted to PCM either by the player or by the processor in order to use any DSP features - speaker distance correction, bass management, room EQ, etc. This can be done "on the fly" in real time from DSD discs or files, which is how I do it.
--DSD from SACD, with some effort, is also now able to be ripped to hard drive for computer playback using certain specific PS3, Oppo, Pioneer, Sony, Cambridge, etc. players plus hacking software. Mch Flac, etc. downloads are increasingly available, usually from the label's site. BD-As can also be ripped, but require extra effort to segment the BD chapters into tracks. BD Videos in Mch are also easily ripped, but they are necessarily huge in size.
-- Analog Mch preamps and analog interconnections are not recommended for Mch, although analog is what goes to the amps and speakers. There are only a few such choices, and they are lacking in features like DSP, and too limiting. There is no possibility of speaker distance/time correction in a Mch analog preamp, and they often lack bass management. However, some purists prefer an identical, equidistant speaker setup and analog Mch preamp for direct DSD to analog playback. It is not worth it in my view.
-- A single master volume control is a necessity. Don't believe you can achieve success cobbling together several old stereo integrated amps or preamp/amps. Each time you adjust overall volume on the several resulting volume controls, you are messing up the interchannel level calibration, which is very important to maintain.
-- What about video? If you look at the speaker layout standards, which are also the mastering standards, for 5.1 Dolby True HD and DTS HD Master Audio, you will find them completely congruent with the ITU standard described here. Mch with video works quite well for me on my music-oriented system.
I will recommend a number of SACD labels I have found to consistently deliver high quality, discrete Mch music newly recorded over the past 15 years or so, as follows:
--BIS
--Channel Classics
--PentaTone
--RCO Live
--Reference Recordings
--Telarc (defunct)
--Harmonia Mundi
--Chandos
--2L, many also on BD-A
--Linn
--many other small European labels, though LSO Live I find sonically mediocre
Also, major labels like DG and RCA have released some good ones, but many fewer than any of the above.
The good or bad news, depending on your viewpoint, is that it is mostly all classical. The Mch Dark Side of the Moon remastering is initially striking, and probably the largest selling Mch SACD ever, but it is a simple repanned "surround sound" mix from the multitrack originals. I don't think it successfully illustrates what Mch can really do, a familiar story with Mch rock, unfortunately. I do very much like the Allman Bros. Live at the Filmore East and Eat a Peach, remastered from Mch Quad era originals from live concerts. I have not found much jazz or other genres that are really good Mch, but I have not searched and listened that extensively for them.
I have built my library around discrete Mch music recordings. Is upmixing from stereo sources to Mch nearly as good? It can be good and preferable to stereo, but, frankly, it does not come that close to discrete Mch in my experience, and it will not reveal how good Mch can really be. I do not listen to much from stereo on my main system, and I prefer to leave that in stereo rather than upmix it.
