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Orchestra/choral records done with omni stereopair with APEs only
Old 4 weeks ago
  #1
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DAH's Avatar
 
🎧 15 years
Orchestra/choral records done with omni stereopair with APEs only

I know, it is not the mic number but how you use it.
However, it is now all I have, namely:
a Korg MR-1000,
a stereopair of free-field B&K 4165 1/2" omnis with B&K 2619 preamps(bodies),
a set of 20, 30 and 40 mm APEs
a B&K 2807 power supply (impedance conditioner with 0 dB gain),
Superlux MS200 mic/overhead stand,

and I want to start with this minimal setup to learn the main pair positioning.

Any classical records made with just a stereopair that can pass as a reference in terms of space, noise level, timbral accuracy? May be old or new, piano+vocalist, baroque ensemble, choir, large orchestra?

I know, the timing is not good to say the least, still I am on pursuit of making some nice minimalist recordings in DSD.

Last edited by DAH; 4 weeks ago at 11:01 PM..
Old 4 weeks ago
  #2
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king2070lplaya's Avatar
Maazel/Pittsburgh Pines of Rome on Sony

Mackerras/SCO Brahms Symphonies on Telarc

Pretty much any Decca solo piano recording, would recommend Pascal Rogé’s Ravel, Thibaudet’s Debussy, pretty much anything Ashkenazy or de Larrocha

Quote:
Originally Posted by DAH ➡️
I know, it is not the mic number but how you use it.
However, it is now all I have, namely:
a Korg MR-1000,
a stereopair of free-field B&K 4165 1/2" omnis with B&K 2619 preamps(bodies),
a set of 20, 30 and 40 mm APEs
a B&K 2807 power supply (impedance conditioner with 0 dB gain),
Superlux MS200 mic/overhead stand,

and I want to start with this minimal setup to learn the main pair positioning.

Any classical records made with just a stereopair that can pass as a reference in terms of space, noise level, timbral accuracy? May be old or new, piano+vocalist, baroque ensemble, choir, large orchestra?

I know, the timing is not good to say the least, still I am on pursuit of making some nice minimalist recordings in DSD.
Old 4 weeks ago
  #3
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hughesmr's Avatar
 
🎧 15 years
Quote:
Originally Posted by DAH ➡️
I know, it is not the mic number but how you use it.
However, it is now all I have, namely:
a Korg MR-1000,
a stereopair of free-field B&K 4165 1/2" omnis with B&K 2619 preamps(bodies),
a set of 20, 30 and 40 mm APEs
a B&K 2807 power supply (impedance conditioner with 0 dB gain),
Superlux MS200 mic/overhead stand,

and I want to start with this minimal setup to learn the main pair positioning.

Any classical records made with just a stereopair that can pass as a reference in terms of space, noise level, timbral accuracy? May be old or new, piano+vocalist, baroque ensemble, choir, large orchestra?

I know, the timing is not good to say the least, still I am on pursuit of making some nice minimalist recordings in DSD.
Pretty much any recording on the Dorian label back in the 1980s/90s would qualify.
Old 3 weeks ago
  #4
Is this something you look for? This is done with a wide A-B. Two tripods on each side of the conductor, probably a width of 1.7 meters). It is a long time ago, 1993.
Attached Files

02 Andante.mp3 (14.38 MB, 1444 views)

Old 3 weeks ago
  #5
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king2070lplaya's Avatar
An example of a very-if-not-too-wide AB orch recording can be heard in the Reiner/CSO “Also Sprach Zarathustra”, which I think was among the first stereo recordings done by RCA in 1954 using 2x widely-spaced U47s. Compare this recording to the later Don Quixote or any of the other recordings by that conductor and ensemble, and you can hear the effect that adding the 3rd U47 or SM2 in the middle of the arrangement had on the stereo field.
Old 3 weeks ago
  #6
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DAH's Avatar
 
🎧 15 years
Yes, to be clear: I value depth and focus, so wide AB is not kind of tech I am looking for, rather I consider ORTF-like width and angle with omni low-end and APEs helping the focus.
Old 3 weeks ago | Show parent
  #7
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king2070lplaya's Avatar
Quote:
Originally Posted by DAH ➡️
Yes, to be clear: I value depth and focus, so wide AB is not kind of tech I am looking for, rather I consider ORTF-like width and angle with omni low-end and APEs helping the focus.
Cool.
Old 3 weeks ago | Show parent
  #8
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🎧 10 years
Quote:
Originally Posted by Orgeltonmeister ➡️
Is this something you look for? This is done with a wide A-B. Two tripods on each side of the conductor, probably a width of 1.7 meters). It is a long time ago, 1993.
No spot ?
Great recording.
The problem I hear with large ABs like here is some phase problems with the double-basses and a distorded stereo image (compared with for example an ORTF)
Old 3 weeks ago | Show parent
  #9
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didier.brest's Avatar
 
🎧 10 years
Quote:
Originally Posted by mathieujm ➡️
some phase problems with the double-basses

Which ones? The phase difference between A and B is the key of the stereo effect. It becomes a problem if it is too large because of too large AB, which would happen first on high frequencies.
Old 3 weeks ago | Show parent
  #10
Quote:
Originally Posted by mathieujm ➡️
No spot ?
Great recording.
The problem I hear with large ABs like here is some phase problems with the double-basses and a distorded stereo image (compared with for example an ORTF)
1. For safety I placed spots at the woodwinds and timpani but they were not used.
2. Thank You !
3. What is wide? I used approx. 1.5-1.7 meters. Not really wide, I would say medium.

Any thoughts about the used microphones? APE's ? Brand/Type?
Old 3 weeks ago | Show parent
  #11
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🎧 10 years
Quote:
Originally Posted by Orgeltonmeister ➡️
3. What is wide? I used approx. 1.5-1.7 meters. Not really wide, I would say medium.
According to Williams curves, 150cm AB gives a recording angle of +-15° !
So the AB should be too far from the orchester to see it within this angle.
It's also my experience : 40 to 50 cm is ok to have a good stereo image with an orchester, less if the AB main is just above the conductor.
Old 3 weeks ago | Show parent
  #12
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king2070lplaya's Avatar
Quote:
Originally Posted by mathieujm ➡️
According to Williams curves, 150cm AB gives a recording angle of +-15° !
So the AB should be too far from the orchester to see it within this angle.
It's also my experience : 40 to 50 cm is ok to have a good stereo image with an orchester, less if the AB main is just above the conductor.
When you use 40-50cm to record an orchestra, are you using outriggers? In my experience, that small of spacing on a large ensemble results in a quite narrow stereo image, which doesn’t convey well the size, power, or dynamic nuance one can hear in a live performance in a hall by the same group.

Maybe it doesn’t follow Williams’ math super well but many recordings I admire are built around AB’s greater than 2’/60cm, and often at or in excess of 3’/90cm.
Old 3 weeks ago | Show parent
  #13
Quote:
Originally Posted by mathieujm ➡️
According to Williams curves, 150cm AB gives a recording angle of +-15° !
So the AB should be too far from the orchester to see it within this angle.
William's SRA is just a theory and works for ideal microphone polar patterns, ideal acoustics where the mix between direct and indirect sound is constant, where all instruments have the same ideal acoustical radiation pattern. None of these things exist in real concert-recording life.


A perfect stereo image even in reality is an illusion, it does not exist. Close your eyes during a concert, and you might experience the sound of the clarinette coming directly from the ceiling of the concerthall.

This recording dates from 1993, the days from mixing directly to stereo 2 track DAT machines, and a maximum of ten minutes to fix a balance before they started recording. Very stressy !
Old 3 weeks ago | Show parent
  #14
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🎧 10 years
Quote:
Originally Posted by Orgeltonmeister ➡️
William's SRA is just a theory and works for ideal microphone polar patterns, ideal acoustics where the mix between direct and indirect sound is constant, where all instruments have the same ideal acoustical radiation pattern. None of these things exist in real concert-recording life.
If the translation to real life conditions were this stringent then I doubt there'd be any meaningful correlation between the theory and practical application, and the entire Williams platform would be next to useless. It isn't ...and I wouldn't be surprised to find that Williams employed extensive subjective listening tests to underpin his theoretical framework. Your characterisation substantially sells his concept short.
Indeed many of the alternative approaches to concert hall measurements (not to mention their architectural design alongside acoustic principles) would be significantly hampered and have little application value, if your assertions were 'necessary conditions'

That microphones are tested in anechoic chambers is undeniable, but that is simply to afford a baseline of consistency...their application in concert halls is hardly a dark art nor the matter of guesswork that you're implying. Can I suggest you peruse F Alton Everest's books as a preliminary challenge to your assertions ?
Old 3 weeks ago | Show parent
  #15
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king2070lplaya's Avatar
Quote:
Originally Posted by Orgeltonmeister ➡️
Is this something you look for? This is done with a wide A-B. Two tripods on each side of the conductor, probably a width of 1.7 meters). It is a long time ago, 1993.
I’m a fan of this! Nice space, too, I assume if it’s 1993 that it’s real?
Old 3 weeks ago | Show parent
  #16
Quote:
Originally Posted by king2070lplaya ➡️
I’m a fan of this! Nice space, too, I assume if it’s 1993 that it’s real?
You mean the reverb? Yes, 100% real acoustics, no artficial reverb.
Old 3 weeks ago | Show parent
  #17
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🎧 10 years
Quote:
Originally Posted by Orgeltonmeister ➡️
A perfect stereo image even in reality is an illusion, it does not exist. Close your eyes during a concert, and you might experience the sound of the clarinette coming directly from the ceiling of the concerthall.
This was recorded with an AB of omnis at 35cm.
I prefer this stereo image.
Attached Files

2016-01-25 Orchestre.mp3 (5.57 MB, 828 views)

Old 3 weeks ago | Show parent
  #18
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DAH's Avatar
 
🎧 15 years
Quote:
Originally Posted by mathieujm ➡️
This was recorded with an AB of omnis at 35cm.
I prefer this stereo image.
Were APEs used? Or just AB? What mics?
Old 3 weeks ago
  #19
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king2070lplaya's Avatar
This is a good thread, thank you both for sharing.

On headphones I think both work well. On speakers, I have a strong preference for the wider setup, though I think I also just like the performance and room more as well, so it’s hard to say anything too conclusive. I think the wider recording actually works better on speakers than on headphones, which was interesting.

The thing I hear in the narrower recording which I don’t love is this center congestion; which is more pronounced on speakers than on headphones (though I do still hear it, specifically in the woodwind passages). The wider recording sounds more relaxed across the middle, though maybe the timpani is a little more diffused on headphones than.... perfect, I guess? But on speakers I don’t feel that way at all, it’s a very full, tight, and powerful sound, and I’m really enjoying it.

I would love to know others opinions or thoughts on what they hear, especially in terms of how the recordings translate for them between speakers and headphones.

Great work, both of you, and thanks again for sharing!
Old 3 weeks ago
  #20
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🎧 10 years
mathieujm's narrower recording sounds as if it was made in a dryer acoustic, with mics closer to the orchestra than the earlier wide pair sample.

While the former probably occupies closer to the 'theoretically ideal' 75-80% of the SRA I also find it a little centre-dense on headphones. The differences in depth detail-retrieval are quite pronounced between the 2 recordings, with more nuanced layering in mathieujm's capture.

Whether that's simply down to the dryish acoustic or closer mic placement is hard to say. Maybe there's a happy medium to be found between these (very substantial !) extremes ?

It would be an interesting experiment to deploy a matched pair of omni mics along a 2m bar, with a servo motor (would have to be silent and well damped vibration-wise !) varying their width from the centre. With this you'd be able to govern their spacing while a performance was occurring.

I suspect that, rather than there being a steady linear progression in perceived image width you'd actually find there to be several nodes or 'pinch points' along the travel where the image slides in and out of coherence and solidity. I guess what I'm suggesting is that there is probably more than a single 'ideal spacing width' for any given AB recording setting...there could be 2 or 3...perhaps depending on choice of repro medium (headphones, speakers or both)

To ease speculation anxiety...it's already been done, with a rig that wouldn't exactly endear one to the video team covering a concert capture. !!

In this particular example (linked below) I'm not sure the chosen antiphonal choral deployment is the best for demonstrating the various arrays...?

https://m.youtube.com/watch?v=fguw5I6MxEo

If you'd like a key to the above video....and I guess the motor(s) just get the mics to the required place, it's not necessary to listen to them while moving !
0:39 AB 80cm omni
0:47 AB 80cm cardioid
1:06 AB 60cm omni
1:12 AB 60cm cardioid
1:22 AB 40cm
1:46 AB 30cm
1:58 AB 30cm cardioid
2:16 NOS(30cm, 90°)
2:40 EBS(25cm, 90°)
3:02 ORTF(17cm,110°)
3:24 DIN(20cm, 110°)
3:46 XY(0cm,-90°)

If you're interested....here's a second sample...same methodology, different church, more orchestral material:

https://m.youtube.com/watch?v=MiL14IdYFRY

Last edited by studer58; 3 weeks ago at 05:25 AM..
Old 3 weeks ago
  #21
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🎧 10 years
Amidst all the roboticism, let's not forget another instrument which has AB miking adherents:

https://m.youtube.com/watch?v=LNfSMnS86ik
Old 3 weeks ago | Show parent
  #22
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🎧 10 years
Quote:
Originally Posted by DAH ➡️
Were APEs used? Or just AB? What mics?
Just a 35cm AB with OM1 mics. No APE.
And an amateur orchestra...

Last edited by mathieujm; 3 weeks ago at 09:29 AM..
Old 3 weeks ago | Show parent
  #23
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🎧 10 years
Quote:
Originally Posted by didier.brest ➡️

Which ones? The phase difference between A and B is the key of the stereo effect. It becomes a problem if it is too large because of too large AB, which would happen first on high frequencies.
Here is the problem on the bass : left and right are out of phase. This is very obvious with headphones.
Attached Thumbnails
Orchestra/choral records done with omni stereopair with APEs only-capture-d-ecran-2021-05-26-105024.jpg  

Last edited by mathieujm; 3 weeks ago at 10:49 AM..
Old 2 weeks ago | Show parent
  #24
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king2070lplaya's Avatar
Quote:
Originally Posted by mathieujm ➡️
Here is the problem on the bass : left and right are out of phase. This is very obvious with headphones.
If these two signals were coming from the same speaker, maybe this would be an issue, but with an AB pair this is a feature, not a bug. For what it’s worth, I don’t notice this at all, on speakers or on headphones, I suppose because those 2 signals never mix and cancel electrically before coming through the playback system.

The problem with too wide an AB pair is that the time delays between mics become so great that the signals decorrelate and become essentially individual mono signals, leading to the hole-in-the-middle sound. That’s definitely not happening in the first example posted here. An easy example though can be heard in the Reiner/CSO Also Sprach Zarathustra recording on RCA from ‘54.

I think your recording actually suffers from too much correlation, especially when listened to on speakers, leading to the congestion of sound I described hearing above. Total phase coherency doesn’t lead to better Sonic outcomes when using AB pairs of microphones at a distance.

I suppose that’s all my own preference, though. I definitely prefer a fat and slightly diffuse omni pair sound over a tight, clinical, precise MS/ORTF/small AB/etc approach for larger ensemble mic’ing, which to me generally sounds too anemic to convey the weight of whatever is in front of the mics.
Old 2 weeks ago | Show parent
  #25
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didier.brest's Avatar
 
🎧 10 years
Quote:
Originally Posted by mathieujm ➡️
Here is the problem on the bass : left and right are out of phase. This is very obvious with headphones.
Indeed there is a strong 63 Hz tone in the time interval of your screenshot (see attached spectrum plot) with perfect phase opposition between L and R channels. Too perfect for being acoustic: see attached screenshot showing the stereo track and below the sum of its left and right channels.(*) Anyway the wavelength at 63 Hz is larger than 5 m. So phase opposition occures for some sound propagation length difference larger than 2.5 m, hence larger than the L and R microphones spacing:
Quote:
Originally Posted by Orgeltonmeister ➡️
What is wide? I used approx. 1.5-1.7 meters. Not really wide, I would say medium.
(*)Edit: screenshot removed because of a dramatic mistake.
Attached Thumbnails
Orchestra/choral records done with omni stereopair with APEs only-capture-1.jpg  

Last edited by didier.brest; 2 weeks ago at 09:24 AM..
Old 2 weeks ago | Show parent
  #26
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🎧 10 years
Quote:
Originally Posted by didier.brest ➡️
Indeed there is a strong 63 Hz tone in the time interval of your screenshot (see attached spectrum plot) with perfect phase opposition between L and R channels. Too perfect for being acoustic: see attached screenshot showing the stereo track and below the sum of its left and right channels. Anyway the wavelength at 63 Hz is larger than 5 m. So phase opposition occures for some sound propagation length difference larger than 2.5 m, hence larger than the L and R microphones spacing:
What I mesure is exactly what Orgeltonmeister told us :
We have a delay of 5ms between R and L for the 63hz. If the double-basses were all on the side of the mics, this gives us the distance between the mics : 543 * 0.005 = 1.70 m !
So nothing else than the distance between the mics is the cause of this "cancelation" of the bass,

And I don't like this. Just do the test of delaying 5ms the right chanel and whit headphones, you will see how the sound is relaxing in the bass.
Old 2 weeks ago
  #27
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king2070lplaya's Avatar
63 hz lies just under the fundamental tone of C2. On neither headphones or speakers do I hear a noticeable cancellation in the contrabass amplitude as we approach that fundamental, nor any shifting of it's location in the stereo image as a result of that visible phase cancellation. Beyond it not looking uniform on a waveform, I genuinely don't see what the issue is.

Again, as long as the signals are routed directly to individual speakers, there will be no electrical cancellation of those signals, and the phase and time differences caused by the mic spacing work acoustically and/or temporally to generate a coherent and correlated stereo image.

Can you please provide a timestamp of where there is an audible negative impact of this out-of-phase character, and describe the effect you hear?
Old 2 weeks ago
  #28
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king2070lplaya's Avatar
I think you're maybe conflating a phrasing issue with a phasing issue, in that the players hold back on the leading tones throughout the passage. But if you listen at around 1:38 to the same passage that you cite in your chart earlier in the piece, you hear a stronger leading tone resolution which doesn't exhibit as much of this effect. Strong C tone. Similarly exhibited at 2:42-2:43.
Old 2 weeks ago | Show parent
  #29
Quote:
Originally Posted by mathieujm ➡️
343 * 0.005 = 1.70 m !
In 1993 we recorded for speakers, we monitored with speakers in separate room. I used Genelec 1019. Headphones were used by the producer to check for mistakes and disturbances, balance was checked on speakers.

I don't think I was so far away with my microphones, probably as close as in the second recording shown in this thread. The church has quite a bit of natural reverb, look at the pictures.

The church is in Haarlem, The Netherlands. It is the church where Harnoncourt and Leonhardt recorded the Bach Kantates in the 1960s.
Attached Thumbnails
Orchestra/choral records done with omni stereopair with APEs only-doopsgezinde-kerk-hlem-alt.jpg   Orchestra/choral records done with omni stereopair with APEs only-dv-hlem-zicht-op-orgel.jpg   Orchestra/choral records done with omni stereopair with APEs only-kerkinterieur-bovenaf.jpg   Orchestra/choral records done with omni stereopair with APEs only-plattegrond-dv-hlem.jpg  
Old 2 weeks ago | Show parent
  #30
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didier.brest's Avatar
 
🎧 10 years
Quote:
Originally Posted by mathieujm ➡️
We have a delay of 5ms between R and L for the 63hz.

The minimum delay that causes phase opposition at 63 Hz is half of a period for a 63 Hz sine waveform: (1/63) / 2 = 7,9 ms.
The sound speed in air is about 343 m/s at 20°C. Hence the minimum propagation length required for phase opposition at 63 Hz is 343×(1/63)/2 = 2,72 m.

Last edited by didier.brest; 2 weeks ago at 10:04 PM..
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