Pink noise volume pan for evaluating stereo imaging

[bigshot]

Depth is enhanced by physical distance and the number of channels. So headphones would have the least depth and an Atmos speaker system would have the most. Sound stage is a flat horizontal plane in front of you. Sound fields extend that sound source from in front of you to behind you. That is depth.

Scale in a speaker system is determined by the distance between the mains. Stereo is limited in scale because if you increase the size of the triangle formed by the mains and listening distance too far, the phantom center falls out. A center channel can extend that distance before gaps in the phantom center by double.

So basically, depth is determined by front to back, and scale is determined by left to right.

 

[gregorio]

I will need more time with a system to tell whether I can for example clearly hear a sense of the woodwinds or trumpets actually being further back on the stage than the strings etc.

That brings us back to where I started, that will depend on the individual recording and how it’s been mixed. IRL, woodwinds and trumpets aren’t really much further back than the strings. In fact the back desks of the strings will only be two or three feet in front of the woodwinds and trumpets. So in some cases the effect will be very subtle, in others somewhat less so but it generally shouldn’t be a particularly obvious effect. The best way to learn how to identify relatively small/subtle effects is to start with big obvious examples and work your way down. For example start with some orchestral recordings of pieces with off-stage instruments (typically brass), also some of the antiphonal choral pieces from the renaissance period recorded in churches are excellent examples.

G

 

[bigshot]

I have a series of multichannel recordings of the Royal Philharmonic that were recorded in such a way that there is a great deal of secondary depth cues on the horns and percussion. It gives the effect of an exaggerated sense of depth.

They’re very odd recordings. The liner notes say that they were recorded multi miked with as many as a hundred channels. That is unusual isn’t it, Gregorio?

 

[gregorio]

I have a series of multichannel recordings of the Royal Philharmonic that were recorded in such a way that there is a great deal of secondary depth cues on the horns and percussion. It gives the effect of an exaggerated sense of depth.

They’re very odd recordings. The liner notes say that they were recorded multi miked with as many as a hundred channels. That is unusual isn’t it, Gregorio?

Sorry, very, very late, only just seen your question.

A hundred channels wouldn’t be unusual if you include all the routing channels; sub-groups, etc. It would be rather unusual if that’s a hundred mic input channels, 30-50 or so would be more usual, although in the case of surround sound or Dolby Atmos it could be more. A hundred isn’t unbelievable.

G

 

[bigshot]

This was a series of recordings of the London Philharmonic in surround. The liner notes explained that between concert seasons and in down time from sessions, they went in the studio and worked their way through recording the orchestra’s core repertoire. They set up a unique system with up to 100 channels and recorded and rehearsed every day for weeks. They had the venue and miking in place so all they had to do is record. Of course the LPO has a wide repertoire, and they used several conductors. It was in the studio, not a venue so the room ambience and overall balance was primarily created in the mix. It sounds like movie soundtrack style. Interesting idea. Is that common?

 

[castleofargh]

Out of curiosity, is there a generally accepted number for "enough voices"? Like maybe after a certain number it starts to inevitably lose coherence because too many people can't be that synchronized, or maybe it just kind of starts sounding the same to us be it 100 or 10000?
I'm sure the main considerations at a pro level are space and money, but usually when I have those questions, many had them long before me.

 

[bigshot]

Coherence into an overall image kind of depends on how well the tracks are balanced. A large number of tracks makes the mix more complicated.

These recordings I’m referring to are weird because they don’t do it the way it’s usually done. It’s organized to take advantage of 5.1. There’s a slice of the orchestra in the rear (percussion primarily) that has its own soundstage with a reverb indicating distance. Then there’s a slice through the middle with brass and woodwinds with less reverb and pinpoint placement left to right. Then the strings extend across pushed slightly forward into the room giving the perspective of the conductor with violins on the left side of the room and cellos on the right. In the rears there’s a natural sounding (but completely concocted in the mix) hall ambience. The effect is to place the orchestra from beyond the front wall of the listening room to the middle of the room, with hall ambience around and behind that..

My guess is that since they recorded hours and hours of music with the same mic setup, they were able to use a lot of the same balance settings in the mix, grouping sections of the orchestra and adjusting them as needed as a group. That would make the large number of channels more manageable. But they still would have the ability to bring up a flute or hold back a trumpet if needed.

It doesn’t sound anything like any of my other orchestral recordings, but it has a certain presence that sounds good and real anyway.

 

[gregorio]

Interesting idea. Is that common?

No, not in England. I’ve never heard of such a thing, amateur orchestras maybe but the professional ones, nope, there’s just not the money to rehearse everyday for weeks. Typically it would be a couple of rehearsal sessions, probably on the same day or spread over a couple of days, then a dress rehearsal on the concert day (that’s usually more of just a run through) and that’s your lot. One rehearsal, then the dress rehearsal and gig is entirely common/usual. Really important gigs with more challenging pieces, such as big premiers of contemporary works, might get 3 or 4 rehearsal sessions possibly 1 or 2 more under truly exceptional circumstances, baring in mind two rehearsal sessions a day or a rehearsal session and gig but I’ve never heard of rehearsing everyday for weeks, I don’t know how that would even be funded. British orchestras, particularly the London orchestras, are well known for their sight reading and short rehearsal skills because of the way they’ve been funded historically, that’s one of the reasons they’re attractive for film score work. “Everyday for weeks” sounds to me like a bit of creative marketing!

If they recorded a lot of different pieces then the same mic setup might be appropriate, in which case using 100 or so would make more sense, although for studio work that would usually not be the optimal way of doing it. They do the BBC Proms with about 130 mics but that’s because they have to set them up before the festival starts and then cover pretty much every sort of classical ensemble imaginable for the next 2 or 3 months with that same setup, which they’ve developed of a period of about 60 years!

Out of curiosity, is there a generally accepted number for "enough voices"?

Not sure what you mean by “voices”, do you mean musicians, mic channels or audio channels? The number of musicians can literally be up to 1,000 (Mahler’s 8th Symphony) and even in the 1830’s, Berlioz’s Requiem was scored for about 450. Orchestra sizes typically top out around 100-125 (Sacre du Pretemps and the Alpine Symphony for example). The number of mic channels will often start to be self defeating from around 50 upwards but there’s no hard rules, it’s dictated by what you’re recording, where you’re recording it and what amount of flexibility you might need when mixing. Film score work commonly uses the most mics but the problems can be reduced with (transparent) screens which provide a little more isolation between the mics. The number of audio channels can be over 400 but that’s really only film scores, where it’s not uncommon to have an entire symphony orchestra plus a MIDI (sample) orchestra mixed together to create a sort of super orchestra (Hans Zimmer pioneered that trick), hence the ridiculous number of audio channels. Film sound is where the channel counts can get really huge, up to about 1,500 or so in some instances (including the music). Typically there would be 3 mix (“re-recording”) engineers working together/simultaneously on a mix of that size.

G

 

[castleofargh]

I'm a little offended to learn that you are not telepaths, because although I worded it in that confusing way, in my mind the question was clear^_^.
I meant a number of voices or instruments that sing/play the same thing. I wrote voices because I started thinking we were probably more tolerant(used) to having many different voices and differences in timing, than we are with instruments. So my intuition was that we could hit a higher limit with singers before it became terrible.

 

[gregorio]

I'm a little offended to learn that you are not telepaths, because although I worded it in that confusing way, in my mind the question was clear^_^.

Some DAWs use the term “voices” (Pro Tools for example) because of the way the “channels” are handled programmatically and the fact that the term “channel” itself can be ambiguous. Actual human voices though, I don’t think there’s much of a limit, Mahler’s 8th is scored for about 850 voices if I remember correctly. Distance becomes the problem eventually though. You sing/play according to what you hear and if what you hear is delayed by several tens of milli-secs (due to the speed of sound), then it can get messy. Orchestras are more used to that issue and the musicians most likely to suffer those problems learn to “anticipate the beat” and reduce it somewhat. This is balanced against the fact that in the early days of sampled orchs we discovered that perfect or even good timing sounded horrifically bad! The software now has pretty decent “humanise” algorithms which include randomising timing (and tuning) between voices.

G

 

[2leftears]

I'm a little offended to learn that you are not telepaths, because although I worded it in that confusing way, in my mind the question was clear^_^.
I meant a number of voices or instruments that sing/play the same thing. I wrote voices because I started thinking we were probably more tolerant(used) to having many different voices and differences in timing, than we are with instruments. So my intuition was that we could hit a higher limit with singers before it became terrible.

Maybe that is also a matter of personal preference?

Too many instruments and/or voices "playing the same thing" as you phrased it is not my cup of tea.

In particular I am not a fan of too many violins playing simultaneously, hence I tend to prefer the sound of a small baroque orchestra to that of a large symphony orchestra; symphony orchestras often sound a bit too 'noisy' to me, even though the 1st and 2nd violins and cellos and basses aren't 'playing the same thing'.

I don't mind a small orchestra with a modestly sized choir, but in the 'choir music' I listen to not too many voices are singing the same thing, it is mostly 15th/16th/17th century polyphonic.

Distance becomes the problem eventually though. You sing/play according to what you hear and if what you hear is delayed by several tens of milli-secs (due to the speed of sound), then it can get messy. Orchestras are more used to that issue and the musicians most likely to suffer those problems learn to “anticipate the beat” and reduce it somewhat.

I always wondered how the musicians themselves deal with this problem. From what I have read some larger church organs can have a noticeable delay between key press and pipe speak on the longer pipes. Must take quite a bit of experience and skill to play a large church organ in time with the orchestra. (I like many of Ton Koopman recordings.)

 

[bigshot]

I don’t mind the numbers of instruments as much as I do masses of instruments playing the same thing. I love the complex string textures of Wagner, but I’m not keen on the Andrew Lloyd Weberesque unison strings of Puccini.

 

[gregorio]

I always wondered how the musicians themselves deal with this problem.

Years of sitting in an orchestra as a teenager, with the conductor regularly stopping the rehearsal and shouting “brass you’re late” (and too loud) and you eventually start to learn! It’s still only a rough guess though as exactly how much to anticipate varies from venue to venue, an orchestra pit (in the case of opera and ballet) is particularly challenging for the inexperienced.

Must take quite a bit of experience and skill to play a large church organ in time with the orchestra.

And generally they’re not! Typically a large church organ is played on its own or sometimes with a choir, very rarely with an orchestra and so they usually don’t have that “quite a bit of experience”. It’s often a challenge, not uncommonly the orchestra has to adapt to the organist more than the other way around, because the organist does not have that “quite a bit of experience” of anticipating the beat to stay in time with an orchestra, the end result is commonly that the timing isn’t great. Fortunately, that’s not so much of a serious issue in a large church, because the timing is pretty blurry anyway due to all the delays and reflections from stone walls, columns, floors, domed/vaulted ceilings, etc. When recording, we will typically position the mics to provide options when editing/mixing, a little “wiggle room to tighten it up a bit”.

An even bigger problem than timing can be the tuning!

G

 

[2leftears]

An even bigger problem than timing can be the tuning!

G

This I can definitely believe!

 

[gregorio]

This I can definitely believe!

Yep, concert pitch today is typically A = 440Hz but go back a couple of centuries or so and it was much higher, a semi-tone or so. A bit uncomfortable to get in tune with that if you’re a singer or string player but certainly doable. Not so if you’re a wind instrument player, other than chopping bits off your instruments with power tools, there’s no solution. Years ago, Durham Cathedral, one of the most famous in the UK, had a wonderful huge period organ. We just could not sharpen our instruments enough to get in tune with it, had to dump it and use an electronic organ and some huge speakers instead, such a shame.

G