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Which Figure-8 Mic For Mid-Side?
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#91
13th November 2011
Old 13th November 2011
  #91
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Quote:
Originally Posted by dseetoo View Post
Schoeps MK8 asymmetrical characteristic is well known and its effect is readily audible, whether used as S mic in a MS configuration or a Blumlein setup. In both cases you would notice losing of high end from the “dull side”. The consequence is more problematic in a MS configuration because you could never decode L/R properly or symmetrically, whereas in a Blumlein configuration, because what you ultimately end up with, the stereo image is symmetrical therefore its asymmetrical response is not nearly bothersome. (So, you lose some high end from the back of the hall.) I use the word bothersome, because I was very bothered by the fact I could never get the whole sound stage to sound symmetrical with a MK8 as S mic. One could “fix” this somewhat by using slight EQ on the “dull side” of the decoded channel. But, using EQ does not really fix the problem, it actually introduces a new problem: because you unavoidably EQing the output of the M mic that is in the matrix as well. I realized, after working with MK8s for a long while (years) the situation is hopeless and I gave up on it.
Of course, the cure is in using a perfectly symmetrical figure 8 mic if MS is your thing, whether it is a true symmetrical capsule like MKH30 or one with double cardioids, (almost 100% of the switchable pattern microphones available use double cardioid principle, LD or SD with the only exception of MK6) One can argue about the sonic attribute of one of those double capsule microphones thus not being suitable as a M mic. A simply solution would be to try to use two of your favorite cardioid microphones, say a pair of MKH8040 or MK4 and place both capsules as close as possible but facing back to back just like what it is in a double capsule microphone to roll your own favorite figure 8 microphone, the equivalent of MKH800 Twin. Make sure you don’t reverse the polarity of either cardioid microphone when decoding with the M microphone. Yes, you would need a third channel in your following chain to accomplish this. A hint: the result could be very rewarding.


Best regards,

Da-Hong Seetoo
Sorry, but to me this statement is confusing, convoluted and not at all helpful. What am I missing?
#92
14th November 2011
Old 14th November 2011
  #92
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"I realized, after working with MK8s for a long while (years) the situation is hopeless and I gave up on it."

Why did you work with it such a long time?
#93
14th November 2011
Old 14th November 2011
  #93
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"The image is more accurate and more solidly positioned, and I put this down to the capsules being able to be located closer together than the other arrays."

It may also be related to the frequency response, and possibly to the
relatively simple single-ended construction.
#94
14th November 2011
Old 14th November 2011
  #94
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dseetoo is offline
I purposely avoided talking about the sound qualities of MK8 in my post. I have MK6, MK8 as well as MKH 30 so I know how they sound and I certainly understand why people prefer one over the other. The sonic attribute was not what I was talking about in my post, nor did I ever say MK8 is dull sounding. For lack of better word, when I say “dull side” I meant the back side, the side has slightly drop of high end comparing to the front side. But since figure 8 can be used either way, 0 or 180 degree, saying front or back is not as to the point. Since I was talking about the asymmetrical nature of the MK8, I choose the word dull. No, MK8 is certainly not a dull sounding mic.

I suppose most of the orchestras you recorded have the viola and cello seated on audience right, or stage left. Therefore, the phenomenal in discussion is not as apparent in your recording. Imagine what happens when you are recoding an orchestra seated like the Vienna Phil, which the 2nd violins are seated on audience right or stage left. Their seating favors the 1st violin section because for most part, the 2nd violin section their instrument is facing the back of the stage instead of audience and they don’t sound as forward as their 1st violin section, not to mention in general, the 1st violin always play higher notes and therefore carry the sound better in the hall. In that situation, MK8 will further exaggerate the un-equal violin sound. Come to think about it, I guess one could setup the MK8 red dot facing stage left to compensate a bit in that situation. Something to think about, at least.

The key ingredient to my suggested double cardioid alternative is to use SD microphones. LD will have too big of a shadow. However, using a pair of good sounding cardioids comes with a lot of interesting benefits; 1, Most of cardioids have better low end than any figure 8 microphone. 2, They are less susceptible to wind noise because they tend to have higher diaphragm tension. 3, By not position them 180 degree you can have certain stereo pickup pattern not obtainable with a regular figure 8. 4, Easily maintain MS symmetry. 5, Ability for independent manipulation of each cardioid electronically before MS decoding. 6, A much bigger pool of good sounding cardioids, thus you get to choose your favorite ones. I dare to assume most of recording engineers will have a least handful of cardioids but not all of them will have figure 8. Again, one has to try this for himself to make your own judgment if this approach works for you, or not. I personally tried this and found the above mentioned benefits and I am sharing them with all of you. Of course, YMMV.


Best regards,

Da-Hong Seetoo




#95
14th November 2011
Old 14th November 2011
  #95
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Fran Guidry is offline
Sir, could we have a bit more detail on the summing and decoding? I just threw up some cardioids here and tried summing them with left mic panned hard left, right mic panned hard right, no inversion.

Then I tried summing the two side facing cardioids with right facing mic polarity inverted, to give something approximating a bidirectional mic. This gave me a "normal" mid-side pair, which required copying and inverting of the virtual "side" mic before decoding.

In the first example there was a noticeable boost to sources in the center position compared to sources at the side. The back-to-back cardioids simply panned and summed lack the null of a bidirectional mic.

Thanks,
Fran
#96
14th November 2011
Old 14th November 2011
  #96
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David Spearritt is offline
Quote:
Originally Posted by dseetoo View Post
However, using a pair of good sounding cardioids comes with a lot of interesting benefits ...
and one of the biggest disadvantages over a genuine fig 8 dipole, that of relatively poor directivity with frequency. A fig 8 dipole has the most constant directivity with frequency of any pattern, and therefore gives the most uncoloured sound rendition.
#97
14th November 2011
Old 14th November 2011
  #97
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Quote:
Originally Posted by David Spearritt View Post
Far be it from me to argue with the venerable Mr Seeto, but reading this thread gives the impression that the MK8 is unusable and dull, which is plainly not the case, as evidenced by the many fine recordings and many users round the world.
Thank you, Dave. Let's all continue to use those tools that please our ears.

D.
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#98
14th November 2011
Old 14th November 2011
  #98
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dseetoo is offline
Quote:
Originally Posted by Fran Guidry View Post
Sir, could we have a bit more detail on the summing and decoding? I just threw up some cardioids here and tried summing them with left mic panned hard left, right mic panned hard right, no inversion.

Then I tried summing the two side facing cardioids with right facing mic polarity inverted, to give something approximating a bidirectional mic. This gave me a "normal" mid-side pair, which required copying and inverting of the virtual "side" mic before decoding.

In the first example there was a noticeable boost to sources in the center position compared to sources at the side. The back-to-back cardioids simply panned and summed lack the null of a bidirectional mic.

Thanks,
Fran





I have to admit that It has been a while since I last used the MS technique…

To use opposite facing double cardioids as a figure 8, you do need to first invert the phase of the right facing one, sum the left facing and inverted right facing together as your true figure 8. The summation can then be used as S mic in a MS setup. This is easier to setup in a virtual environment than actual hardware. Simply sum two opposite facing cardioids without inverting one of them would yield an omni mic. Sorry for the confusion.

Da-Hong
#99
29th November 2011
Old 29th November 2011
  #99
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Jörg Wuttke's MK 8 measurements

Further comments received today from Jörg Wuttke about Schoeps MK 8:

### BEGIN ###

Hello Michael, I am back from Paris and you are waiting for further comments. Here they follow:

Let me first comment on the remark that someone claims that “Schoeps measures microphones up close - not at a reasonable distance of 1m”. As you will have understood by my previous mail this is a wrong statement. However, it is true that one microphone manufacturer is really measuring at a distance of 33 cm but SCHOEPS is not doing that.


This time I enclose a copy of measuring results that show the possibilities how good figure of eights can be. The MK 8 is among the best dipoles that exist on the world market. Famous recording engineers like Tony Faulkner would approve.


As mentioned in my earlier mail it is possible to compensate for having a flat response down to lowest frequencies but the danger of high sensitivity against air movements and solid born noise rises. The DSP-Box made by SCHOEPS for the Polarflex technique contained an EQ. The second attachment shows how much compensation was applied.


Please understand that I cannot write a book within an mail. Some of my papers are available in German on the SCHOEPS homepage
www.schoeps.de and on my own www.ingwu.de But I see it coming that two more questions will come up, so I prefer to answer now:

1. The low end response of omnis seem always to be better than that of figure of eights even if they are perfectly equalized. If EQ is exaggerated the sound gets muddy.


The reason:


Most room problems are low frequency problems. The smaller the room is the less you have natural harmonics (Eigenfrequenzen). If an electrostatic omni is positioned in the antinode of the pressure at least all the corresponding frequencies will be transmitted without any attenuation.


The number of antinodes of the velocity is the same as for the pressure but now the microphone must also be directed in the right direction because the velocity is a vector. For this reason dipoles capture only one third of the Eigenfrequencies. At low frequencies there are often not enough of them, especially in smaller rooms.


2. Some people noticed that the sound on axis differs from the sound received at 180°.


The reason:

All these people tested their microphone with an earphone. Listening with an earphone to your own voice means that you get two signals. The one that travels directly through the head and the electrically transmitted sound. The second is reversed in polarity speaking on the rear of the dipole. This effect can be avoided if the phase switch on the amplifier is reversed if the microphone is turned by 180°

Best regards,


Jörg


### END ###
Attached Thumbnails
Which Figure-8 Mic For Mid-Side?-mk8_research.jpg   Which Figure-8 Mic For Mid-Side?-mk-8-rohr-eq-dsp.jpg  
#100
30th November 2011
Old 30th November 2011
  #100
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Another word -PlugIns- from Schoeps

I received this today from Jörg (he knows, btw, that I post all his comments here for the slutz):

###BEGIN###

Hello again Michael,

Helmut Wittek informed me that the new Polarflex-plugin and the double-MS-plugin both contain the EQ for the MK 8. Both are free and can be downloaded from the SCHOEPS homepage.

Best regards

Jörg

###END###

Apparently, Schoeps' approach is to put the fig-8 corrective EQ in the plugin where we can control it rather than fixed EQ values in the microphone.

Here's what the literature says: "The Polarflex plug-in mixes two capsules in three different frequency bands such that the level and the frequency response of the diffuse sound and with that the directivity of the micro-phone is altered. The plug-in automatically maintains the overall level at all frequencies which means that every possible setting leads to a potentially useful result. "

I'm glad Schoeps gives users control over the fig-8 EQ while maintaining overall signal level (a function of the plugin), rather than putting a fixed EQ correction in the microphone itself. This aligns with their long-held philosophy of giving engineers flexible tools that can be applied in many practical situations. The challenge, at least for me, is to think like an engineer and use the tools thoughtfully!

Plug-in for RTAS, VST, VST3, AU Polarflex - Overview - SCHOEPS.de
Surround Plug-in for RTAS Mac, VST Windows/Mac Double*MS*Tool - Overview - SCHOEPS.de
.
Attached Thumbnails
Which Figure-8 Mic For Mid-Side?-polflexpluginlegend2.jpg  
#101
2nd December 2011
Old 2nd December 2011
  #101
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Quote:
Originally Posted by MichaelPatrick View Post
Apparently, Schoeps' approach is to put the fig-8 corrective EQ in the plugin where we can control it rather than fixed EQ values in the microphone.
This raises the question of which is more desirable to have electronic
eq built into a mic, or to add eq in post.

One problem of having built in eq is that it is not possible for the eq
to be ideal for every recording situation, so it may be necessary to
eq it again in post anyway, which could involve undoing what the
built in eq is achieving.

An advantage though, of having built in eq, is if it happens to be just
right for a particular situation, then the signal can be monitored
without guessing as to what the final recording will sound like.
#102
2nd December 2011
Old 2nd December 2011
  #102
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Quote:
Originally Posted by aracu View Post
This raises the question of which is more desirable to have electronic
eq built into a mic, or to add eq in post.

One problem of having built in eq is that it is not possible for the eq
to be ideal for every recording situation, so it may be necessary to
eq it again in post anyway, which could involve undoing what the
built in eq is achieving.

An advantage though, of having built in eq, is if it happens to be just
right for a particular situation, then the signal can be monitored
without guessing as to what the final recording will sound like.
Yes, this makes good sense.

I think Schoeps is addressing the market for electronically-controllable patterns, saying that you can effectively employ fig-8s, omnis and cardioid-variants; you don't have to buy a special purpose mic (i.e. soundfield-type) if you've already got some Schoeps capsules with these fixed patterns.
.
Attached Thumbnails
Which Figure-8 Mic For Mid-Side?-polar1.jpg   Which Figure-8 Mic For Mid-Side?-polar2.jpg  
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#103
2nd December 2011
Old 2nd December 2011
  #103
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Theoretically this creates an ideal spaced pair for a given space.
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