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Speaking of MS
Old 11th October 2019
  #31
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Quote:
Originally Posted by didier.brest View Post
No comb filtering in MS because M and S are in-phase at any frequency.
Re the oft touted 'mono compatibility' of MS...when the signals from an MS stereo mic are mixed to mono, the resulting signal is from the front facing mid capsule only.

If the mid capsule is cardioid, sound sources derived from the far left and far right are going to be attenuated, thus the balance might indeed be different between stereo and mono, so you'd be better off using coincident XY instead ?

In opposite fashion the central image of an ORTF is comprised of well off axis cardioid capsules

Another disadvantage of MS is that the stereo spread and direct to reverberant ratio are interdependent: you can't change one without changing the other.

The early findings (in the 70's and 80's, by Griesinger I think ?) were also critical of MS's lack of warmth and spaciousness...and I think that's why he proposed giving the low frequencies a shelving boost of 4dB (+2dB @ 600Hz) in the side signal and a complementary shelving cut in the L+R (mid)

Has anyone tired this and found an increase in spaciousness ?
Old 11th October 2019
  #32
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emrr's Avatar
Quote:
Originally Posted by studer58 View Post
The early findings (in the 70's and 80's, by Griesinger I think ?) were also critical of MS's lack of warmth and spaciousness...and I think that's why he proposed giving the low frequencies a shelving boost of 4dB (+2dB @ 600Hz) in the side signal and a complementary shelving cut in the L+R (mid)

Has anyone tired this and found an increase in spaciousness ?

That would sound a bit crazy with MKH mics in every instance I've recorded. They have bass, in fact I usually have to take some out of the side.
Old 11th October 2019
  #33
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Quote:
Originally Posted by emrr View Post
That would sound a bit crazy with MKH mics in every instance I've recorded. They have bass, in fact I usually have to take some out of the side.
Maybe the complementary mid-mic bass-cut would offset that boost, in the final matrixing balance ? A similar principle was employed in the Gerzon and Blumlein 'shuffler' circuits.

See 'Spaciousness and spatial equalization' in link below....

https://books.google.com.au/books?id...zation&f=false

There's also a wealth of stereo related documents here, including a good outline of orchestral spot and sectional miking methods, from Dieter Beheng (of Deutsche Welle Radio Training Centre: Stereo Recording Techniques):

http://tbbaliverpool.com/wiki/files/...d-f6a478aee336

Last edited by studer58; 11th October 2019 at 02:59 PM..
Old 11th October 2019
  #34
Gear Addict
 

Quote:
Originally Posted by studer58 View Post
Re the oft touted 'mono compatibility' of MS...when the signals from an MS stereo mic are mixed to mono, the resulting signal is from the front facing mid capsule only.

If the mid capsule is cardioid, sound sources derived from the far left and far right are going to be attenuated, thus the balance might indeed be different between stereo and mono, so you'd be better off using coincident XY instead ?

In opposite fashion the central image of an ORTF is comprised of well off axis cardioid capsules

Another disadvantage of MS is that the stereo spread and direct to reverberant ratio are interdependent: you can't change one without changing the other.

The early findings (in the 70's and 80's, by Griesinger I think ?) were also critical of MS's lack of warmth and spaciousness...and I think that's why he proposed giving the low frequencies a shelving boost of 4dB (+2dB @ 600Hz) in the side signal and a complementary shelving cut in the L+R (mid)

Has anyone tired this and found an increase in spaciousness ?


With MS, you need a full spectrum signal from both microphones, especially the S microphone in order to correctly decode the directionality. Whatever the signal is missing from the S microphone, that signal will be only presented in the M channel, thus mono sound. Figure 8 microphones have traditionally been poor in their bass response and I suspect that is the reason people tend to think MS lacks some “spaciousness”. With any other none-coincident technique, there always will be some time/phase difference in the two channels to give your ears/brain some locational cue , even if the bass is greatly reduced, such as using two figure 8. So, the key is to make sure the S microphone has decent bass response to begin with if you want to do MS.
Old 11th October 2019
  #35
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MKH 30 bass is not reduced though
It has eq and proximity cut if needed
They are not bass light and make a perfect MS pair.
Old 11th October 2019
  #36
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MKH30 is better than most of figure8 in regard to bass. But, it is only properly compensated down to about 50Hz. However, it can go lower if the internal bass end of the circuit is reworked.

In a large concert hall, you never have to worry about proximity problem. If MS is used as main pair, it is at least 20 feet away from the bass or tuba section, most likely a lot further than that. At that distance, you lose low end really quickly in a concert hall.
Old 12th October 2019
  #37
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Quote:
Originally Posted by dseetoo View Post
MKH30 is better than most of figure8 in regard to bass. But, it is only properly compensated down to about 50Hz. However, it can go lower if the internal bass end of the circuit is reworked.
How can a pressure difference microphone be "bass compensated" ? Long wavelengths will produce next to nothing pressure difference at the capsule dimensions.
Old 12th October 2019
  #38
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Quote:
Originally Posted by David Spearritt View Post
How can a pressure difference microphone be "bass compensated" ? Long wavelengths will produce next to nothing pressure difference at the capsule dimensions.


Hello David,

I trust you know the story behind the MKHXX microphone design. As such, the circuitry in MKHXX microphone employs EQ for high end as well as low end. It also has HPF in every of MKHXX microphone. The capsule of MKH30 does pick up a lot of low end information but the circuitry actively cuts it out. They did that deliberately, for their reasoning. The same MKH30 can go much lower if the circuitry is modified. I know this because I did that to mine.


You can verify this by doing the following two ways;

1 Inserting a LPF in my Brahms Symphony No.2 recording and see how much more bass is coming front the right channel than the left. (Double bass section is to the far right) As you know, without the bass information from MKH30, you will not have bass localization information in decoded stereo.


2 Reverse the phase of one channel and then combine them into mono, doing which will cancel out the M signal altogether but restore the entire MKH30 signal. Now listen to it and see how much bass is in the recording. It will surprise you as how much real bass this MKH30 picks up, certainly a lot more than stock MKH30.




Best regards,


Da-Hong
Old 12th October 2019
  #39
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boojum's Avatar
I think some confusion has arisen from the fact that the original mics used for Blumlein and MS do not have the same good specs as those do today. I use the Samar VL373A and its specs are 20 Hz to 25 KHz. This is not bass shy. The MKH30 claims 40 Hz to 20 Khz and Da-Hong has altered his MKH30 circuits to extend the bottom end lower. So to write off MS/Blumlein as bass-shy is a dated and broad generalization.

And as was mentioned upstream, if a great recording can be made with carbon mics, great. It is a fact that MS will give accurate recordings of spaciousness and clarity. This has been demonstrated in this thread. This is not rocket surgery. It is out there for those who want it.

Dixi.
Old 12th October 2019
  #40
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Quote:
Originally Posted by boojum View Post
I think some confusion has arisen from the fact that the original mics used for Blumlein and MS do not have the same good specs as those do today. I use the Samar VL373A and its specs are 20 Hz to 25 KHz. This is not bass shy. The MKH30 claims 40 Hz to 20 Khz and Da-Hong has altered his MKH30 circuits to extend the bottom end lower. So to write off MS/Blumlein as bass-shy is a dated and broad generalization.

And as was mentioned upstream, if a great recording can be made with carbon mics, great. It is a fact that MS will give accurate recordings of spaciousness and clarity. This has been demonstrated in this thread. This is not rocket surgery. It is out there for those who want it.

Dixi.
Gerzon and Griesinger were writing in AES papers in the late 1980's about spatial equalization, shuffling and such, and I don't think the fig 8 mics of that time (ie well after the RCA 44/77 era !) were particularly compromised in bass extension, compared with today's offerings ?

In addition, it wasn't just confined to MS/fig 8 mics: in Bruce Bartlett's book on location recording he writes:

"Gerzon notes that spatial equalization is best applied to stereo microphone techniques not having a large antiphase reverberation component at low frequencies, such as coincident or near-coincident cardioids. With the stereosonic technique of crossed figure-eights, antiphase components tend to become excessive. He suggests a 2.4dB cut in the sum (L+R) signal and a 5.6dB boost in the difference (L-R) signal for better bass response.

Griesinger states 'Spatial equalization can be very helpful in coincident and semi-coincident techniques [especially when listening is done in small rooms]. Since the strongest localization information comes from the high frequencies, microphone patterns and angles can be chosen which give an accurate spread to the images at high frequencies. Spatial equalization can then be used to raise the spaciousness at low frequencies' "

So these guys were proposing relatively simple adjustments made on the basis of perceived shortcomings of (several) miking techniques...and they remain today for us to test and verify, at our leisure... and if curiosity leads us there.

I suspect there's some inherent 'cringe factor' at play here, whereby adherents to a particular miking method (not necessarily just MS) feel slighted that their 'elegantly simple' methods must never be capable of enhancement, as if there might be an unspeakable, inherent flaw... which must be brushed aside and dismissed whenever it appears.

But isn't the advancement of science and greater knowledge generally typified thus: neat elegant theory brutalized by gangs of ugly facts ?
Old 12th October 2019
  #41
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Quote:
Originally Posted by dseetoo View Post
Hello David,

I trust you know the story behind the MKHXX microphone design.

Da-Hong
Hi Da-Hong

Yes, I am not referring to the circuitry. I refer to the fundamental fact that a fig 8 mic is a pressure difference transducer and is at the mercy of wavelength for low frequency pickup.

I am still amazed, despite Yannick's very convincing demo from a few years ago, that a 16mm diameter capsule (characteristic dimension) can render a pressure difference worth amplifying for signals having a wavelength of 6m (50Hz) and longer. With ribbons this dimension is much smaller, 2 or 3mm hence much less pressure difference.

I admire your continued efforts to extend the frequency responses of your mics. I am not so interested in the extremes of the audible frequency range.

Regards
David
Old 12th October 2019
  #42
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boojum's Avatar
OK, OK, you've moved me. My W10 has been stopped with malware, my router too, and two phones. I have been running Linux Mint for a month or so now. Which means I am now forced to learn Reaper, which is a good thing. I will try that add/subtract bass just to see how it sounds. And then I'll say it does not work. No, no, joking. I will make two files, one with no adjustment and one with and then AB them.

Let's neither of us lose sight of the fact that my technical underpinnings are shaky. But I do know how to experiment. Give me some time as I have to find the time and learn the new software and I understand that Reaper has a pretty steep learning curve. But Samplitude is not intuitive. None of it is.

Cheers

Last edited by boojum; 12th October 2019 at 07:46 AM..
Old 12th October 2019
  #43
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Quote:
Originally Posted by boojum View Post
OK, OK, you've moved me. My W10 has been stopped with malware, my router too, and two phones. I have been running Linix Mint for a month or so now. Which means I am now forced to learn Reaper, which is a good thing. I will try that add/subtract bass just to see how it sounds. And then I'll say it does not work. No, no, joking. I will make two files, one with no adjustment and one with and then AB them.

Let's neither of us lose sight of the fact that my technical underpinnings are shaky. But I do know how to experiment. Give me some time as I have to find the time and learn the new software and I understand that Reaper has a pretty steep learning curve. But Samplitude is not intuitive. None of it is.

Cheers
Is learning Reaper for you the equivalent of reading a book by candlelight, after the town's power supply goes down after a big storm ?

I'm going to try the same GG (Gerzon/Griesinger) tricks with some of my ORTF recordings...to see if I can turn them into lovely AB omni captures with some simple shelving eq

I'm not expecting transformative miracles, but just to see if they can wring out any helpful changes !

BTW, Reaper is blessed with some powerful video tutorial musclepower, to add some serious incline to your learning curve....especially from these 2 guys : Kenny Gioia

https://www.youtube.com/channel/UCq2...GSsQ/playlists
https://www.youtube.com/channel/UCq2...VFHGSsQ/videos

and Jon Tidey: https://www.youtube.com/user/audiogeekzine/playlists
Old 12th October 2019
  #44
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boojum's Avatar
Thanks for the YouTube links.
Old 12th October 2019
  #45
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Quote:
Originally Posted by boojum View Post
Thanks for the YouTube links.
No worries...as we say in Oz, they're "heaps good" ! The hard part is knowing what you don't know...and then finding the video solution to that
Old 12th October 2019
  #46
Many thanks for the links Studer58 - very useful!! (I did not realise you are in Oz!)
Old 13th October 2019
  #47
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Yannick's Avatar
 

As mentioned above:
MS stereo does not collapse to mono at LF

This mod for the MKH30 does interest me. But is there a significant difference with doing it with a digital EQ afterwards ?

IME ms recording with MKH series mics do not suffer at all from a lack of warmth nor bass, when done correctly (insert good hall and good ensemble).

What does go on is a combination of things. Using more directional M mics tends to sound a bit thinner than more omni M mics, because the former picks up less of the hall acoustic, and thus less bass buildup in the hall. I sometimes compensate with a very slight EQ (generally 1-2 dB is more than enough)
When comparing to spaced omnis, ms can sound thinner. A lot depends on the playback system and room. In my setup AB recordings almost invariably sound too thick. Hf directionality, exaggerated sub bass pickup, and things are made worse by the complex comb filtering in the mid frequencies, which does substract a lot of information there, rendering the playback even darker.

Imo, historically, AB has been considered superior, and maybe was at a certain point. It is my personal opinion that, given the potential for superior playback in our current times, MS is most often the more accurate approach. Tonally as well as imaging.

I know many very good AB recordings, but there are very few that surpass merely sounding like a good recording.

I am stuck on location, so have not been able to listen to the examples here. Very anxious to do that.
Old 14th October 2019
  #48
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Quote:
Originally Posted by Yannick View Post
As mentioned above:
MS stereo does not collapse to mono at LF

This mod for the MKH30 does interest me. But is there a significant difference with doing it with a digital EQ afterwards ?

IME ms recording with MKH series mics do not suffer at all from a lack of warmth nor bass, when done correctly (insert good hall and good ensemble).

What does go on is a combination of things. Using more directional M mics tends to sound a bit thinner than more omni M mics, because the former picks up less of the hall acoustic, and thus less bass buildup in the hall. I sometimes compensate with a very slight EQ (generally 1-2 dB is more than enough)
When comparing to spaced omnis, ms can sound thinner. A lot depends on the playback system and room. In my setup AB recordings almost invariably sound too thick. Hf directionality, exaggerated sub bass pickup, and things are made worse by the complex comb filtering in the mid frequencies, which does substract a lot of information there, rendering the playback even darker.

Imo, historically, AB has been considered superior, and maybe was at a certain point. It is my personal opinion that, given the potential for superior playback in our current times, MS is most often the more accurate approach. Tonally as well as imaging.

I know many very good AB recordings, but there are very few that surpass merely sounding like a good recording.

I am stuck on location, so have not been able to listen to the examples here. Very anxious to do that.
do you ever use a/b? if so, for specific genre or ensembles/instruments?
Old 14th October 2019
  #49
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Quote:
Originally Posted by boojum View Post
I'm on board, again.

!snip!..... But I fall back on two techniques on a regular basis: MS and ECA. Earcatcher's ECA posts are transcendant....... !snip!.

Sorry for not knowing, but what is ECA?

Many thanks,
-09
Old 14th October 2019
  #50
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Quote:
Originally Posted by Omicron_9 View Post
Sorry for not knowing, but what is ECA?

Many thanks,
-09
“ECA”-Earcatcher Array, is a proprietary mic array developed by the forum member Earcatcher.
Old 14th October 2019
  #51
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Yannick's Avatar
 

Quote:
Originally Posted by deedeeyeah View Post
do you ever use a/b? if so, for specific genre or ensembles/instruments?
My business partner is sometimes quite fond of AB setups, so we sometimes do dual setups. Most often, the MS setup wins in the studio. By far.
Interestingly, on location, on headphones or bad monitoring conditions, the difference is smaller, or even favorable for the AB setup. Food for thought.
Old 14th October 2019
  #52
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Quote:
Originally Posted by Yannick View Post
My business partner is sometimes quite fond of AB setups, so we sometimes do dual setups. Most often, the MS setup wins in the studio. By far.
Interestingly, on location, on headphones or bad monitoring conditions, the difference is smaller, or even favorable for the AB setup. Food for thought.
pretty much the same over here: except for occasional (stereo) recording of instruments/ensembles which heavily rely on the room (such as an organ or choir on which a/b imo has some merits) and for ambis, i mostly put up a/b or oss just to give a producer an option to choose from but otherwise rely on x/y, m/s, soundfield or ortf.

what's your experience with double m/s?

regarding monitoring on headphones: similar experience until i started using a crossfeed matrix - wouldn't wanna work wiithout any as the difference between listening on cans and speakers gets much smaller and so the advantage of less correlated sound from a/b systems compensating for the typical effect of hearing inside the head mostly disappeared :-)
Old 15th October 2019
  #53
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boojum's Avatar
Quote:
Originally Posted by Omicron_9 View Post
Sorry for not knowing, but what is ECA?

Many thanks,
-09
Search for Earcatcher and you will find some of his posts of sound files. The array is able to capture a more "whole" impression of the venue and the sound within it, IMO. It has been a contentious array on the board as Earcatcher has not divulged its secrets.
Old 15th October 2019
  #54
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Tommy-boy's Avatar
 

Quote:
Originally Posted by Orgeltonmeister View Post
Beautiful sound and natural balance, but speaking of the "hole in middle" effect, that is what I actually hear here. I would not have expected that with MS. Is the S signal louder than the M?
I thought the same as I listened.

Tom
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