Multichannel Audio (Moved from MQA)
May 13, 2017 at 1:28 PM Thread Starter Post #1 of 116

bigshot

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1A,) Adding a centre channel doesn't make the soundstage larger, it just makes the centre more focused. In a home listening environment it's arguable that having an actual centre channel (as opposed to a phantom centre) is pointless, it's only essential for large spaces (such as cinemas).

B.) I don't understand your comment about sound not coming at you from all directions? It would have to come at you from all directions to create the illusion of being in the middle of the room!

C). What sound from Sgt Pepper would be placed in a vertical dimension? Also, I don't think you've understood the design/purpose of Atmos or the state of technology to generate a 3D space (synthesize an acoustic ambience) "with pin point accuracy" or the ability to reproduce that in a home environment. In significant respects, technology can't even do this with 5.1 yet, let alone with Dolby Atmos!


A.) The size of the soundstage is determined by the width between the speakers. with stereo at a normal listening
distance, you don't want more than 8 feet or so between the speakers. If you push them any wider apart, you have to sit further back, which reduces the perceived size of the soundstage. But with a center channel, you can double that, with 8 feet between each of the three speakers. 16 feet wide plus the added throw to the side of the outside speakers brings the size of the stage up to around 20 feet, which is still manageable for a large living room, but puts the soundstage into a human scale. It's the audio equivalent of the difference between watching a 40 inch TV or seeing a movie projected on a ten foot screen.

B.) There are two philosophies for mixing multichannel music... Ping Pong and Immersive. Prog Rock like Pink Floyd has lots of overdubbing of details and fills that lend themselves to the ping pong approach. The rhythm section is anchored up front, but the solos and fills get thrown to individual speakers- left, right, rear left, rear right- bouncing around the listener like a ping pong ball. Immersive is quite different. Instead of using each channel as a discrete channel to place sound into, the mixer creates a sound field from all of the channels combined. The sound meshes into the phantom center of all 5 speakers, so it can be moved to any point in the room by potting it a bit in one direction or another. The two mixing philosophies can be blended too. There is an Elton John SACD where the piano and drums are fixed up front to the left and right. The vocals come through the center channel. At the bridge, a guitar solo is introduced, but it is mixed immersively. It starts up front in the center, and as the volume increases, it's potted toward the rears. This gives the impression that the guitar player is stepping forward in front of the rest of the band to take his solo. If you close your eyes you can place the player clearly about 6 feet in front of the rest of the band. There are classical multichannel mixes that exactly reproduce ambiences of concert halls, opera houses or cathedrals. The meshing of the five channels creates a three dimensional ambience with different reverberation and decay to each side of the listener. You not only hear the music, you hear the size and construction of the space it's inhabiting.

The problem is that with immersive mixes, the devil is in the details. You have to have a really well suited room and very carefully calibrated speakers to get them to mesh properly. If they are poorly meshed, the phantom centers drop out and the sound starts to come from the corners of the room, not the middle. Most people who have multichannel systems use it primarily for movies and don't bother to go the extra mile to properly calibrate it for music. That requires precise EQ to assure timbre matching of all of the speakers and careful level balance to bridge the center without making any single channel overbearing. Not as easy as it sounds, but it is possible.

C) Sgt Pepper is an album that completely lends itself to the most complicated multichannel mixing techniques. There could be sections that could have an open air ambience contrasted against parts with a very enclosed small ambience. When they pull apart all of the overdub tracks by going back and rebuilding them from the 4 track premix elements, they'll end up with close to a full 24 track master full of separate parts. That will give them a lot of flexibility to create any kind of multichannel effect they want.

5.1 creates a sound field that is a flat plane- left, right, back, front. Atmos adds speakers above to create a plane like that above the listener's head. This creates a cubic sound field. Using immersive mixing, this makes it possible to not only place sound in the left/right/front/back plane, but in a vertical dimension too. Sounds could be placed anywhere in the room at any height. Music could erupt out of the floor and fly into the air above like a volcano. It could fill the room from the bottom up like water filling a fish tank. You could have one part of the music moving across the floor from front to back while another part goes above your head from back to front. Think about how Strawberry Fields would sound if the music was handled like flowing water. "Picture yourself on a boat on a river" "No one I think is in my tree. I mean it must be high or low." There are a million possibilities for using height to indicate being underwater or in the sky or swirling in circles.

Martin did a multichannel mix of ta pastiche of Beatles songs called the Love album. It's a real kaleidoscope of what multichannel music can do. Before it came out, people were scoffing it saying "What can be done with 40 or 50 year old recordings?" They didn't think that multichannel could add much. They were dead wrong. I think the same can be true of Atmos. It still hasn't been confirmed that the blu-ray will include the Atmos mix. It might just be for theatrical demonstrations. Like I said before, it requires a carefully designed multichannel installation to get the most out of these sorts of mixes. Not everyone with a 5.1 system is going to be able to pull it off.

EDIT: One side comment... there was some discussion of how most home 5.1 systems are "adequate" to create coherent multichannel audio. This isn't true. Most people with 5.1 use the "home theater in a box" kits with tiny satellite speakers on stalks and a woofy black sub on the floor. It's almost impossible to get a sound field to mesh with a system like that because of the extremely limited frequency response of the mains and massive dropouts in-between them. What you end up with is sound coming from the corners of the room and nothing in the middle. In order to create a coherent sound field, you need full range speakers all around and they need to be EQed and level balanced so sound can be handed off from any of the other speakers without a dip in the middle or a timbre shift.
 
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May 14, 2017 at 12:23 PM Post #2 of 116
Essentially, you seem to have created your own concept of how surround sound works and is mixed, unfortunately, your concept does not appear to actually match the reality.

A. Adding a centre channel does NOT allow a wider stereo image, it just provides an anchored centre. Any signal which is perfectly correlated in both the left and right channels (which would therefore be the phantom centre) would instead be routed to an actual centre channel/speaker. What about any signal which requires output from both speakers but is not perfectly correlated, say any stereo effect, reverb or signal not positioned hard left, hard right or dead centre? Doubling the distance between the left and right speakers has the same effect on these signals regardless of whether there's a discrete or only a phantom centre! Maybe you've got (or heard) a system setup that way and liked it but that just means you liked a less accurate stereo image. Ultimately this is a function of the mix and therefore you typically can have the left and right speakers further apart in a 5.1 setup than in a stereo setup not because a centre channel can double the width but simply because it's been mixed that way.

B. There is in a sense two philosophies of mixing sound but they are NOT the two philosophies you've described! In practice, pretty much all mixes (stereo or surround) are a sort of mixture of what you're describing. Maybe in the early days of stereo they were thinking in terms of only discrete left and right (plus phantom centre) and crudely bouncing between them but not for decades. Throughout the 70's (and onwards) we saw the introduction of true stereo (rather than dual mono) effects and in popular music genres, the creative application of stereo effects. The concurrent use of very different effects, for example, a very large gated reverb on the snare, at the same time as little/no reverb on say the kick and bass guitar, at the same time as say a plate reverb on the lead vocals, at the same time as a big stereo delay on the lead guitar, at the same time as a medium chamber on the backing vocals. This is about as far away from any concept of a live performance or real acoustic as it's possible to even imagine but this is basically how all popular music is mixed! The reason mixing this way works, when logically it shouldn't, is because starting in the 60's bands/producers/engineers started to experiment and gradually (over the course of 15-20 years or so) discovered that they could completely divorce "reality" (real sounds, real acoustics, real performances) and "what sounds good". This is quite different to most classical music production, which is all about authenticity; real sounds, real acoustics and real performances. In film, where the use of surround is most evolved, we are to a certain extent creating authenticity but generally it's at least partly and commonly entirely created artificially, with the use of mainly mono and stereo source sounds. Furthermore, true 5.1 reverb is only just now starting to become available, all reverbs were effectively mono in, 5.1 out and for this reason two stereo reverbs were sometimes employed instead. Your concept of 5.1, effectively providing a square within which one positions the elements of a mix, might sound logical but it's not the way it works in practice because in practise it would not work! The translation wouldn't even work between say a Dolby certified dub stage and a Dolby certified cinema, let alone in a consumer environment. In practice 5.1 is essentially used as a set of linked stereo soundfields, L - R, Ls - Rs, L - Ls and R - Rs and often as just two stereo soundfields L - R and Ls - Rs. Positioning a sound within the square (as you suggest) is generally avoided unless the sound is moving/panning, to avoid the high likelihood of phase issues between all the speakers (and resultant reflections) on playback in a different environment. As evidenced by numerous films, it's entirely possible to create an immersive experience this way.

C. No, Sgt Pepper wouldn't lend itself to either simple or complex multichannel techniques. What you seem to be talking about is a relatively simple/straight forward stereo mix with just a coherent surround ambience, as opposed to a surround mix. Even just this simple approach is likely to problematic due to how it was likely originally recorded and the fact that a coherent ambience is only just becoming technically possible for 5.1 and is years away for Atmos. I'm sure, given the original recordings and sufficient experimentation time that a top pro could come up with something that sounds decent but it's not going to be substantially more than a stereo mix + reasonably convincing ambience, unless of course you get gimmicky and/or substantially change the music arrangements.
[1] Most people who have multichannel systems use it primarily for movies and don't bother to go the extra mile to properly calibrate it for music. That requires precise EQ to assure timbre matching of all of the speakers and careful level balance to bridge the center without making any single channel overbearing.
[2] 5.1 creates a sound field that is a flat plane- left, right, back, front. Atmos adds speakers above to create a plane like that above the listener's head. This creates a cubic sound field.

1. To be honest, that's fairly backwards! To a greater or lesser extent, music is abstract and that's why there is no standard music studio calibration. Film on the other hand typically/often deal with sounds that are not abstract, sounds in acoustic spaces which people encounter all the time. Therefore there needs to be (and is) a standard calibration for cinemas and dubbing theatres. In practise, the translation of music between different recording studios is usually acceptable but typically completely falls to pieces with TV/movie sound.

2. No it doesn't, I think you've misunderstood how Atmos works. 5.1 does produce a flat plane, what Atmos does is to allow us to access individual speakers for individual sounds in that flat plane rather than just zones of speakers. It also provides access to two rows of ceiling speakers. Rather than thinking of Atmos as a coherent cube, it's more accurate to think of it as a standard 7.1 environment, plus the option of accessing individual speakers with individual sounds both in that 7.1 environment and speakers in the ceiling. Atmos is very clever and sophisticated but it does not provide the coherent 3D space you imagine (and the marketing implies) and even if it did, the tools do not currently exist to use that potential to actually create a coherent 3D space and even if we had both of these, the difference between what you would end up with and a traditional 5.1 mix would be minimal in most music applications.

G

Caveat: Much of what I've said above is rather over simplified and not entirely true but it's as close as I could get in the time. I could probably show you in 5 mins but trying to explain it in a text post is not optimal!
 
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May 14, 2017 at 9:08 PM Post #3 of 116
Do you have a multichannel speaker system yourself?
 
May 15, 2017 at 7:09 AM Post #4 of 116
Do you have a multichannel speaker system yourself?

At this instant in time I don't have a surround system at home, although I did have one from about 2005 until recently and will have again at some point. However, I started working with surround sound in 1996 (LCRS) and then with 5.1 in 1998, the majority of my professional career since then has been on surround sound projects and therefore I've had a multichannel system in my personal studios continuously for over 20 years. Additionally, my work often entails taking the materials I've created, recorded, edited or mixed to other studios for final mixing (in the case of theatrical release films). So I've a fair experience of a number of commercial theatrical dub stages, including a few world class ones and I recently worked at a Dolby Atmos certified dub stage, where I was shown by the resident re-recording mixer how it's used in practise (during a free hour or so, as the film we were mixing was only 5.1).

G
 
May 15, 2017 at 11:39 AM Post #5 of 116
Multichannel music has evolved an awful lot recently. When you set up your system again, I think you'll be surprised at what engineers are doing with it. It's moving towards dimensional sound for music, not just directional sound like it was in movies in the beginning. Even some recent remixes of movies for blu-ray are going in that direction now. It does require more careful calibration to pull off though. I learned a lot by calibrating my system.

If you get a chance to audition a really good surround system, check out The Beatles: Love and Elton John: Honky Chateau (or Goodbye Yellow Brick Road.) Both of those are mixed entirely differently than standard 5.1 for movies. The soundstage in the Elton John albums is remarkably realistic, And Rocket Man has the part where the guitar player walks from the front wall to the middle of the room. Love has some parts where the sound washes in from the rear or swirls around the room like a whirlpool- dimensional effects. If Love is any indication, I'd love to get a chance to hear the new Sgt Pepper mix with Atmos. When I get a moment, I'll list some more interesting and innovative surround mixes that I've heard. There aren't a lot of them, but they're pretty interesting to break down and figure out how they work.

It helps to have a large scale system, not one where the speakers are all tight together like home theater in a box setups. It's hard to get tiny satellite speakers to mesh. Full range speakers all around are much better. I don't know if the average person will ever go to the trouble to put together a good 5.1 system for their home, but those of us who have certainly reap the rewards when it comes to the aural presentation when it's done right.
 
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May 16, 2017 at 6:50 AM Post #6 of 116
Multichannel music has evolved an awful lot recently. ...
If you get a chance to audition a really good surround system ...
It helps to have a large scale system, not one where the speakers are all tight together like home theater in a box setups.

I don't think you read beyond the first sentence of my last post!

G
 
May 16, 2017 at 5:35 PM Post #7 of 116
No, I read it. I just replied to your comments where I could tell you understood what I was saying. If you get to LA, look me up and I'll audition my 5.1 system for you and show you what I've been able to build. Multichannel music is a relatively new thing and it's quite different than what you seem to be familiar with. It's a different mindset than for movies. I think it might surprise you.

The Sgt Pepper blu-ray comes out in a couple of weeks. Unfortunately, my listening room has a high peaked roof, so I can't do Atmos. There is a new Kraftwerk album in 3D sound that uses Atmos too. I'd be very interested to hear what Atmos can do for multichannel music.
 
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May 17, 2017 at 7:53 AM Post #8 of 116
[1] Multichannel music is a relatively new thing and it's quite different than what you seem to be familiar with.
[2] It's a different mindset than for movies.

[3] The Sgt Pepper blu-ray comes out in a couple of weeks. Unfortunately, my listening room has a high peaked roof, so I can't do Atmos. There is a new Kraftwerk album in 3D sound that uses Atmos too.

1. Not really, it started in the early '70's but died a death. Then there was a resurgence in the early '00's with the launch of SACD and DVD-A and a number of artists released material, some of it just gimmicky (like early stereo), some of it not so gimmicky but still nothing to really write home about and some of it, mainly classical, essentially just stereo with surround ambience. Only the latter gained consistent acceptance but it's still a tiny niche. Popular music genres have had many years to learn, experiment and evolve but it simply hasn't worked. They have continued to evolved but within stereo. There are two basic problems: A. It takes more time, more money, more expertise and better facilities to create surround music, at a time (from the early '00's) that the industry was being forced into music production with far less time, less money, less expertise and cheaper facilities! And B. Baring in mind the coherent/realistic acoustic space limitations with surround, the fact that popular music genres are highly abstract and eshew coherent acoustic spaces anyway, the localisation of sounds within the surround sound field is highly problematic. This would also be true of film if it weren't for the fact that it's usually far less abstract and contains visual cues. This all steers surround music production towards either very obvious/gimmicky placement or just stereo placement + a surround ambience. That's not to say that anything other than these two extremes is impossible, just that in practice it's tricky to avoid them and avoid localisation issues for the consumer.

2. I'm not sure that's really true, certainly there's nothing you've described which isn't either standard film practice or been used on occasion, let's not forget that surround sound has been the de facto film audio format for 35+ years! Even if your statement were entirely true, that still doesn't change the fundamental facts, limitations and dangers of working in surround. Potential phase issues between the speakers for example.

3. To take advantage of the "audio object" based operation of Atmos obviously requires that you've got some audio objects in the first place! It's unlikely that these are available or could be extracted from the Sgt Pepper recordings which, if memory serves, were multi-tracked to 4 track tape. It would be difficult enough to make something in 5.1 from those tapes without being just gimmicky or effectively stereo + ambience! Obviously, if you compose and record an album for mixing in 5.1 or Atmos in mind from the outset, you can ensure having the raw materials to use the format to it's full effect but still, there's the issue of point B above to overcome.

G
 
May 17, 2017 at 11:55 AM Post #9 of 116
The Sgt Pepper 5.1 mix is being reconstructed from the original stems, not the mix downs. Abbey Road meticulously archived all the dub elements and session notes for the Beatles albums. George Martin's son Giles is in charge and he meticulously rebuilt all of the elements in the digital realm matching to the original mix. From what I've read, they've been able to eliminate a lot of noise and distortion and control the balances with much more precision. There's a cleaned up 2 channel mix that matches the original and a totally new 5.1 mix which is said to have elements that not only go around the edges of the room, but diagonally across it as well. The multichannel mix was done with Atmos, but I haven't heard confirmation if the blu-ray includes the Atmos mix yet. The new Kraftwerk set is definitely Atmos and it includes both 3D video and what they are calling 3D sound- placing elements of the music in precise spots within the sound field. You might want to google a bit and see if you can figure out how they're doing it. Interesting how technology and techniques evolve.

There's recently been a bit of a comeback of multichannel lately, not for mainstream music but for specialty stuff aimed at a specific audiophile audience. Multichannel specialists like Steven Wilson have been putting out 5.1 remixes of a lot of classic 70s "prog rock" albums. Realistic multichannel sound fields capturing actual concert hall ambiences are quite common in classical and Lee Ridenour has done some very sophisticated stuff in Jazz too. The new approaches are starting to cross into music video on blu-ray. SACD and DVD-A are on their last legs as formats, but blu-ray as a format for multichannel music is going strong. When you get your 5.1 system set up again, I'll let you know a few recent titles to look for. It's come a long way since Quad back in the 70s, and it's continuing to evolve.

I have both the Sgt Pepper and Kraftwerk 3D sets on pre-order. I'll report back when I receive them (although I can't do 3D video or Atmos).
 
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May 18, 2017 at 5:10 AM Post #10 of 116
[1] The Sgt Pepper 5.1 mix is being reconstructed from the original stems, not the mix downs.
[2] ... and a totally new 5.1 mix which is said to have elements that not only go around the edges of the room, but diagonally across it as well.
[3] The new Kraftwerk set is definitely Atmos and it includes both 3D video and what they are calling 3D sound- placing elements of the music in precise spots within the sound field.
[4] You might want to google a bit and see if you can figure out how they're doing it. Interesting how technology and techniques evolve.
[5] Realistic multichannel sound fields capturing actual concert hall ambiences are quite common in classical and Lee Ridenour has done some very sophisticated stuff in Jazz too.
[6] When you get your 5.1 system set up again, I'll let you know a few recent titles to look for. It's come a long way since Quad back in the 70s, and it's continuing to evolve.

1. A stem is a mix-down! A "stem" is a logical sub-mix of elements, for example with an orchestra the stem mixes would typically be the sections of the orchestra (strings, brass, woodwind and perc). These stems are then mixed together, allowing balancing (and potentially other processing) between the stems during final mixing. However, there is no way of accessing or processing any of the individual sounds/instruments within each stem. So for example, no way of processing (inc. panning/positioning) the violins separately from the violas, cellos and basses. You also have to bare in mind that 24 track recorders would not become available until about a decade after Sgt Pepper, all they had at the time was 4 track. So all they can have is either: 4 mono stems, 1 stereo + 2 mono stems or 2 stereo stems. Most likely one of the last two options.

2. Well that depends on what's on the stems, how the instruments are distributed on the stems. For example, in US recording studios 3 track recorders were common in the late 50's for about a decade, typically the whole band were recorded to 2 of the tracks (in stereo) and the third track was used for lead vocals. In this case, the lead vocals are an audio object which can be positioned in a surround field independently of the rest of the band but none of the instruments within the band can be positioned separately, you're essentially stuck with the stereo positioning baked into the band stem. You can of course move/position that stereo stem anywhere around the surround field but obviously you're moving/positioning the whole band (minus lead vocals), not any individual part of it. However, it's hard to imagine placing that band stem anywhere other than the typical stereo position, without it sounding strange and/or gimmicky. You could of course add a surround ambience to this band stem, a different amount or even a different ambience to the lead vocal stem but that's still tricky because there would already be ambience baked into the stems. Also, if they have got an audio object going diagonally across the surround field, that sounds like the epitome of "gimmicky" to me!

3. Yes, placing individual elements (audio objects) in precise spots around the surround field is exactly what Atmos is good at. Although this is more applicable to theatrical sound systems than home systems.

4. I don't need to google it, I've seen it first hand and even tried it myself, as I mentioned in the post you've said you read.

5. Capturing/Recording a live surround field takes expertise to do well but it's not "sophisticated", in the sense that manufacturing a surround field is.

6. I have a 5.1 system set up and have had continuously for 20 years, as I mentioned in the post you've said you read! I just don't currently have a home/consumer 5.1 setup, only a professional 5.1 setup. Also again, I know how far surround production has come from Quad in the '70's and that it's continuing to evolve, it's my job to know and be part of that evolution! Thanks for your offer to recommend recent titles though. It's possible I might have heard some of them but I can't play bluray disks directly in my studio and have no facility to decode/rip them.

G
 
May 18, 2017 at 12:04 PM Post #11 of 116
Sorry if I incorrectly used the term "stems". Sgt Pepper is being reconstructed from the original recordings used to create the mix downs. They archived every piece of tape from the sessions and had notes on how each mix down was created.

Sgt Pepper is an exceptional album. It was built differently than most recordings at the time and has lots of multi tracking, overdubs and effects. It lends itself to a gimmicky mix. I'm eager to hear what Giles Martin has done with it because he did amazing things with 5.1 on the Love album. I'm sure adding Atmos to the mix opened up a lot of opportunities for new immersive mixing techniques.

Most recent 5.1 mixes are on blu-ray. The exception to that is Steven Wilson's releases which are on DVD-A for some weird reason only known to Steven Wilson. I could list a few suggestions to listen to, but they would be on blu-ray. It might be worth picking up a blu-ray player for your studio. I have an Oppo that plays just about every format in my system.

A friendly suggestion on formatting... It would be a lot easier to carry on a discussion if you didn't do line by line replies. Brief paragraphs with a summary statement in the first and/or last sentence are much clearer. I usually limit myself to three points in a single post to avoid making reading a chore. Line by line replies also make you sound argumentative, which I'm sure isn't your intent.
 
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May 19, 2017 at 5:18 AM Post #12 of 116
[1] It was built differently than most recordings at the time and has lots of multi tracking, overdubs and effects.
[2] I'm sure adding Atmos to the mix opened up a lot of opportunities for new immersive mixing techniques.

1. I don't think you realise what that means in practice, with the technology of the time. They had 4 tracks and that was it, there was no way to increase that number as the technology for more tracks wouldn't become available in the UK for several years after Sgt Pepper and the technology to increase track count by sync'ing different tape machines was likewise years away. So at that time, "lots of multi-tracking" did not mean recording to lots of tracks! For example, let's say you record drums and guitars to 2 tracks (in stereo) and McCartney and Lennon's vocals to each of the remaining two tracks. Then you want to do some overdubs ... where do you record those overdubs, you've used your 4 tracks up. In practice, you'd have to record say McCartney's vocal first, to track 3, "punch in" (and overwrite track 3) for overdubs and then maybe apply effects on track 4. Now we want to record Lennon's vocals but we've no tracks left, so we're going to have to "bounce down" tracks 3 and 4, mix them in with tracks 1 and 2 (guitars and drums), which frees up tracks 3 and 4 for Lennon but of course that means we now have a stereo stem comprised of drums, guitars and McCartney's vocals (inc. overdubs and effects) and no way to separate any of these elements for additional processing or different positioning. In other words, the more multi-track recording, overdubs and effects, the more bouncing down and consolidating of those recorded tracks is required and the less opportunity for subsequent processing/positioning. That was just a potential example, I've no idea what instruments/sounds/effects were assigned to which tracks, what order they were recorded, what the required bounce downs contained, at what point those bounce downs occurred or what their archival strategy was. But a couple of points should be fairly obvious: Firstly, the impressive planning and skill required to take advantage of the opportunities 4 track presented (what to assign to which tracks, when to record each element and when/what to bounce down) and secondly, that this process does not lend itself to subsequent remixing in surround. Again, that's not to say it's necessarily always completely impossible, it depends on the archival strategy, the assignment of elements to tracks and other factors, I'm just saying that it's far from optimal, particularly if compared to a recording made today, where are the tracks and effects can be arranged specifically for mixing in surround. And also baring in mind that even with such an optimal arrangement, still no one has made a surround song/mix which is so good the public has flocked to it and convinced the artists and music industry to head in that direction.

2. Hopefully, point #1 has explained the difficulties of separating out elements in recordings of that era in order to have material to put in the 5.1 channels. Atmos is effectively a 7.1 mix with up to 128 "audio objects" which can be precisely positioned but of course that requires even more separate elements. Of course, this doesn't matter if all we're doing is essentially a stereo mix and adding a surround ambience to create an "immersive" feel but then there's going to be little audible difference between a 5.1 and an Atmos mix.

G

PS (1). Again a caveat: As this is the science forum, it's not absolutely true to state/imply that it's always impossible to move different elements of a stereo track into other channels in the 5.1 sound field.
PS (2). Sorry for still separating out by point. My intention is not to be argumentative but simply to present the relevant practical facts, which in this case is difficult to do without being able to simply show you. So, it's easier for me to go point by point and it's up to you if you find it too much of a chore to go through them all, although of course we're in danger of going round in circles if you don't. :)
 
May 19, 2017 at 8:06 AM Post #13 of 116
1. I don't think you realise what that means in practice, with the technology of the time. They had 4 tracks and that was it, there was no way to increase that number as the technology for more tracks wouldn't become available in the UK for several years after Sgt Pepper and the technology to increase track count by sync'ing different tape machines was likewise years away. So at that time, "lots of multi-tracking" did not mean recording to lots of tracks!
Yup, just 4 tracks, that's it. The possible exception was for "A Day In The Life", where they supposedly figured out how to synch two 4 track machines (one for the orchestra) using a 50Hz signal, so goes the legend, though I've never heard the details, and it would have required a synch mark like a movie clap-stick.

It would have been possible to dub all 4 tracks to the second 4 track machine before each bounce, but that would slow the process. It would, however, be the only way to provide an "undo". No idea if that was done, or if all those steps were kept.
2. Hopefully, point #1 has explained the difficulties of separating out elements in recordings of that era in order to have material to put in the 5.1 channels. Atmos is effectively a 7.1 mix with up to 128 "audio objects" which can be precisely positioned but of course that requires even more separate elements. Of course, this doesn't matter if all we're doing is essentially a stereo mix and adding a surround ambience to create an "immersive" feel but then there's going to be little audible difference between a 5.1 and an Atmos mix.
Yeah, my feeling exactly. What Giles Martin did with Love was not just a 5.1 remix, he created something entirely new using out-takes, demos, rehearsals, and recording new material. It was for a special purpose (Love, the Cirque show). I'm not sure I even like the idea of a 5.1 Sgt. Pepper if he's doing that again, though I did love Love. Love. (Had do put in the third one, cuz...all you need is.....)
 
May 19, 2017 at 1:56 PM Post #14 of 116
Gregorio. the description of how the Sgt Pepper sessions were tracked has been the subject of numerous articles, and there's a lot of info out there about what Giles Martin is doing with the remixes. When they recorded Sgt Pepper, George Martin figured out a jury rigged method of locking multiple four track machines together to create the sub-mixes. There were mix downs from four track as well. Songs like Strawberry Fields and A Day In The Life had more mix downs than other songs. But the technology of the day and generation loss introduced noise and distortion. Since the album was first released, every copy has come from the final two track master. But Giles Martin has gone back to the original raw recordings and has rebuilt them from the ground up in the digital realm, peeling back all the noise and distortion. There will be several remixes... a reconstructed mono mix following the Beatles' approved mix, a mix that opens up the mono mix into a stereo spread, and a totally new 5.1 Atmos mix that reimagines the album in surround. I hear that there are special 5.1 mixes created for the promotional films the Beatles made for the album too. I'm most interested in the 5.1 mixes myself, because the Love album is one of the most forward thinking 5.1 mixes I've ever heard. I can listen past a little noise and distortion, but Sgt Pepper is a kaleidoscope of an album, and it lends itself perfectly to 5.1. The reports are that the results are amazing, and they're talking about going back into other Beatles albums and outtakes and doing the same with them.

http://www.latimes.com/entertainmen...t-pepper-50th-anniversary-20170405-story.html

Steven Wilson has been doing the same with 70s and 80s prog rock albums. He has done dozens of 5.1 remixes of Jethro Tull, Yes, XTC, Anthony Phillips, Steve Hackett, etc. He also goes in and rebuilds from the multitrack sources and creates a reimagined 5.1 mix. I'm not as fond of prog rock, but I still pick up his work because it's fascinating to see how much flexibility there is in old multitrack masters. Early on, Elton John did some astounding surround mixes of his albums, but those were the exception rather than the rule. Most SACD 5.1 mixes are pretty conservative and don't really take full advantage of the medium. That is changing now, but the new stuff is mostly on blu-ray along with video content. A perfect case in point is the Roy Orbison B&W Night remix that just came out. The original mix was typical ping pong with elements isolated in specific speakers or pairs of speakers. The new mix presents it as an immersive soundstage, with some very well crafted engineering. It's like two quite different shows, but they share the same original master.

Lots of legacy titles have masters that could serve to create interesting 5.1 mixes. The biggest limitation to 5.1 sound isn't so much the number of tracks on the master, but the real estate in the living room and what wives will allow. I'm single, so I can indulge in it all I want!

By the way, if you're interested in early multitrack rock recording techniques, Frank Zappa's family has released a 4 CD set called MOFO (Making of Freak Out). IFreak Out was produced by Tom Wilson in 1965 and it pre-dated Sgt Pepper in the way it built up complex layers of sound. (John Lennon said Zappa was one of the primary influences on Sgt Pepper.) The box set separates out the mix down elements and throws in rehearsals and alternate takes to give you a good idea of how the album was constructed. It was pretty revolutionary- it was the first double LP rock concept album,, and it was also Zappa's debut record. The CD set is like pulling apart a Chinese puzzle box to figure out the secrets. Well worth getting and studying.
 
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May 20, 2017 at 1:29 PM Post #15 of 116
1. The possible exception was for "A Day In The Life", where they supposedly figured out how to synch two 4 track machines (one for the orchestra) using a 50Hz signal, so goes the legend, though I've never heard the details, and it would have required a synch mark like a movie clap-stick.
2. It would have been possible to dub all 4 tracks to the second 4 track machine before each bounce, but that would slow the process.
3. What Giles Martin did with Love was not just a 5.1 remix, he created something entirely new using out-takes, demos, rehearsals, and recording new material.

1. I didn't know that rumour/legend. If I had known, I would've asked George Martin about it but we only discussed Sgt Pepper for a few minutes, as I figured he was probably sick to death of being asked about it. He did say in passing that "we only had 4 tracks" but he could've meant in general for the album. I can't imagine how they could've achieved decent sync-lock without the tape drive mechanism being designed for it and the use of time-code for positional ref but that was 25 years before I got involved with recording technology.

2. Yes, they did bounce to a second machine but almost never more than twice, due to noise. I don't know about tape availability at the time and if they reused any of them but knowing Abbey Road, once a reel had been bounced (and not reused) they'd have carefully archived/stored it. There's still the problem of what/how they recorded though, for example, it was mentioned that the whole drum kit was recorded to a single track (mono).

3. Ah, that's a bit different then! Adding new/different material would solve some of the problems of separation and having enough material for the additional channels, I was under the impression that we were talking about the same musical arrangements just made into 5.1.
1. When they recorded Sgt Pepper, George Martin figured out a jury rigged method of locking multiple four track machines together to create the sub-mixes.

2. By the way, if you're interested in early multitrack rock recording techniques ...

1. If true, that would have given them 8 tracks (or more, in increments of 4 tracks per machine), which is contrary to what George Martin told me. They definitely did bounce down to a second machine but the machines were not sync-locked, so they couldn't play both tapes at the same time. In other words, once bounced to a new tape, recording/mixing switched to that new tape and the old tape (from which they bounced) was of no further use. I can't rule out that they did lock two machines for a particular song but not for the vast majority of the album.

2. To be honest, I'm not really particularly interested. I've never researched it, just picked up a bits over the years from conversations with those directly involved at the time. Building up complex layers was pioneered by Phil Spectre, pre-dating Sgt Pepper by about a decade and Les Paul was doing overdubs even earlier. Multi-track recording technology was led by the US and us Brits were playing catch-up, although we did come up with innovative production techniques, Joe Meek being a particularly influential example. I am familiar with Zappa's work BTW.

Apart from some technical misconceptions about the surround formats, our disagreement might also be simply one of personal taste and expectation. I have a very high expectations (because I'm so used to it) and while I've heard some interesting uses of surround in music production there's nothing which has blown me away. With stereo, the popular music genres quite quickly evolved to take advantage of it and eventually we saw some great music which was reliant on stereo. That hasn't happened with surround, it's either just stereo + surround ambience or effectively stereo composition/arrangements with some extra parts in unusual positions. No one seems to be thinking in terms of surround composition, just typical composition which is then mixed in surround. Maybe it's just not possible, maybe music is too abstract and the added complexity of multichannel just doesn't work beyond positional gimmickry? Whatever the difficulties in this regard with 5.1, they're only exacerbated with Atmos but to be honest, I see little advantage for the consumer with Atmos anyway. It's a significant step forward in cinemas, where we've typically got around 30-100 speakers but of very limited benefit in a home environment.

G
 

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