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MKH 30 / 30 MS imaging Condenser Microphones
Old 6th June 2016
  #121
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Quote:
Originally Posted by aracu View Post
Do you mean, by physically aligning the microphone capsules as close as
possible, and then possibly moving an audio file in post to synch up the
waveforms more closely?
Yes, more or less and yes.

If you look at the pic in post 116 (which is quite a good setup btw, I do not understand why the poster apologizes for this one), you can see that if you aim this (vertically) towards the source, the centre sources will arrive completely in time in both capsules. (if you point the array down towards the sound source)

However, due to the height of the mic setup, the musicians sitting towards the side (and below) of the array, will get into the Side mic slightly early. This can be solved by delaying the side mic 1 or 2 samples in post. This causes the mid to be early on centered sources, so it makes sense to retract -physically- the mid mic a few mm to compensate for your digital-post-compensation. Makes sense ?

If you do not do this physical adjustment, then the centered musicians will tend to collapse into mono if you do the 2 sample adjustment on the side mic, because the mid mic is early.

Of course, I agree there is no way to get this completely right.
But it easy to get it quite wrong and conclude MS images badly.
It is also incredibly important to get this more or less right when comparing Blumlein MS to Blumlein XY, as in the MS version you are summing the capsules.

One has to get the hang of it, to decide to do slight adjustments on the spot. Dependes on the height of the main mic, on the width (and depth) of the source, and on what you want to prioritize in the imaging department. Also, aiming at the back or rather the front of an ensemble (for balance purposes) will have an impact on imaging precision of certain groups.
Old 6th June 2016
  #122
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voltronic's Avatar
 

Quote:
Originally Posted by Yannick View Post
If you look at the pic in post 116 (which is quite a good setup btw, I do not understand why the poster apologizes for this one), you can see that if you aim this (vertically) towards the source, the centre sources will arrive completely in time in both capsules. (if you point the array down towards the sound source)
I was apologetic because I really wanted to get the capsules closer - they are about 1cm apart. But it was frustratingly difficult because the old mounts they were in had extremely tight cradles with extremely loose and worn out elastic, and these are the older CMC5 bodies that have almost a velveteen texture on them. As a result, I was risking breaking the A20 cradle every time I tried to move the mics even a few mm.

Quote:
However, due to the height of the mic setup, the musicians sitting towards the side (and below) of the array, will get into the Side mic slightly early. This can be solved by delaying the side mic 1 or 2 samples in post. This causes the mid to be early on centered sources, so it makes sense to retract -physically- the mid mic a few mm to compensate for your digital-post-compensation. Makes sense ?

If you do not do this physical adjustment, then the centered musicians will tend to collapse into mono if you do the 2 sample adjustment on the side mic, because the mid mic is early.
The height was not at all what I wanted - I was forced to use that placement because I needed to be right in front of the conductor. Behind him would have blocked the main center aisle of the orchestra section, which the school would not allow for a live concert because of safety reasons. So I knew that the front row of singers would be very overbalanced in both mics (and they were).

I'm very interested in your suggestion of delaying the side mic and sliding back the mid. I might try this if forced into the same arrangement again, but it sounds very touchy. It seems like it would be very easy to go too far and then introduce phase problems. But could that then be solved by adding slightly more delay to the mid?

In any case, I was very happy with the lateral imaging considering the poor placement. There are samples posted here if you care to listen.
Old 6th June 2016
  #123
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No one can say MS is easy, but once it is mastered, with the right tools,now readily available, it is very reliable .
It is fallible, all techniques are, MS needs attention to some processing detail ,and good placement, and encouragement to the novice, not harassment of self interest
Old 6th June 2016
  #124
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boojum's Avatar
Quote:
Originally Posted by Rolo 46 View Post
No one can say MS is easy, but once it is mastered, with the right tools,now readily available, it is very reliable .
It is fallible, all techniques are, MS needs attention to some processing detail ,and good placement, and encouragement to the novice, not harassment of self interest
Agreed, but I alternately praise and curse Blumlein for this array. It is a wonderful tool and can yield great results when applied with care. OTOH it excites more discussion and bickering than an election. I guess we can expect that sort of thing here. MS vs the world excites almost as much ire as SD vs Nagra. And the SD vs Nagra was slain when no one, not one single person, could tell which file was which when the test was first posted with unattributed files.

Is this a great board or what?
Old 4 weeks ago
  #125
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Quote:
Originally Posted by David Spearritt View Post
For example, the absolute minimum centre distance between your beloved MKH30 caps in MS Blumlein is approx 44mm! As 4kHz sound has a wavelength of 86mm, if a 4k sound arrives at your MS pair (extreme angle example), one channel picks it up at full positive amplitude and you then add this to a full negative amplitude from the other mic in the matrix to get one of your MS channels.

So from 4kHz and above its anyone's guess what sort of nonsense you are baking into the signals. With pure Blumlein none of this happens.
Bumping this thread - I never really thought about this but it seems obvious now.

I've used MS a lot. I have a pair of MKH30's, as well as some other fig 8's. It's usually worked best for me when I had no choice but to set up very close to the ensemble and use an omni mid.

It works as a problem-solver in that regard but it's never my go-to. I love the flexibility but the sound has never been as good as other methods when I A-B them. Too many variables to attribute this summing issue I suppose, but it makes me wonder if anyone can hear what's going on or if it's not really that audible:

Do people who don't like MS just tend to prefer spaced methods etc or is there something audible here that is turning people off?

And what about Soundfield mics? How do they deal with this with multiple capsules several mm apart?
Old 4 weeks ago
  #126
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Soundfield capsules are spaced as close as physically possible in the array
Even vertically mounted fig 8s head to head will be spaced when they are tilted, hence no difference to fore and aft or side by side technique
In practice this makes very little difference, real life halls are full of reflections and nodes
The essence is proper placement, as ever.
This applies to all arrays, which all have nightmarish problems with HF phases
The other essence is, less is more.
Roger
Old 4 weeks ago
  #127
Gear Addict
Quote:
Originally Posted by leddy View Post
Bumping this thread - I never really thought about this but it seems obvious now.

I've used MS a lot. I have a pair of MKH30's, as well as some other fig 8's. It's usually worked best for me when I had no choice but to set up very close to the ensemble and use an omni mid.

It works as a problem-solver in that regard but it's never my go-to. I love the flexibility but the sound has never been as good as other methods when I A-B them. Too many variables to attribute this summing issue I suppose, but it makes me wonder if anyone can hear what's going on or if it's not really that audible:

Do people who don't like MS just tend to prefer spaced methods etc or is there something audible here that is turning people off?

And what about Soundfield mics? How do they deal with this with multiple capsules several mm apart?
Soundfield mics have capsules that are very close together and the phase accuracy is further improved by their
dedicated preamp/processors ( all Soundfield mics except the SPS200).
The SPS200 conversion from A-format
(capsule outputs) to B-format is done
in software which also improves the phase accuracy. Of the Soundfield mics,
the DSF-1/DSF-2 (which have digital processing in their dedicated preamp/processor) have the best phase
accuracy of all Soundfields. The ST450
MKll has the best phase accuracy (reportedly up to 15K) of any analog Soundfield mic.

While there is no phase correction when using MKH30's in an MS pair( whether side-by-side or nose-to-nose) I'm not sure it matters. They can be used for great sounding recordings-witness Rolo's wonderful recordings.
I have a DSF-1 and recently got a pair
of MKH30's and at some point I will try
to do a head to head recording (jangling
keys?, metal clicker?) to try and and assess the phase accuracy in practice.

Any other sound source that I should record?
I was planning on recording sounds while walking around the mics in a circle as well
as a vertical "floor to above my head" movement.

Last edited by Folkie; 4 weeks ago at 12:47 AM..
Old 4 weeks ago
  #128
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Jangling keys is a helluva test
We used to submit radio mics to it and be amused by the absolute strangulation of the companders
Wether it will demonstrate phase disparity will require a goniometer and common sense
Where the MKH 30 scores is its pristine fig8 clarity of propagation, low noise and good bandwidth and smallish size
My 1950s bronze PGS ribbons are rather big, heavy, very magnetic and FM bandwidth limited ( They were designed for the opening of that BBC band in 1953)
Roger
Old 4 weeks ago
  #129
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Quote:
Originally Posted by Rolo 46 View Post
Where the MKH 30 scores is...
I also think the off-axis response of the MKH30 is smoother than any other mic I've compared it to.
Old 4 weeks ago
  #130
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My thought with jangling keys and my clicker is that transients will sound less precise/crisp if there is any phase
cancellation and especially if summed to
mono.
Old 3 weeks ago
  #131
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MS with a fig 8 mid is different from a Blumlein array in that it's geometry is not fixed in place. It can be used closer than a Blumlein array, to create a closer and wider stereo image, by adjusting the ratio of mid to side (having a higher ratio of side).

This is similar to making the angle of the two mics in a Blumlein array further apart than 90°, bringing the side quadrants further back from the ensemble.
Old 3 weeks ago
  #132
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Quote:
Originally Posted by aracu View Post
MS with a fig 8 mid is different from a Blumlein array in that it's geometry is not fixed in place.
Identical until you change the gain of either mic.

Quote:
It can be used closer than a Blumlein array, to create a closer and wider stereo image, by adjusting the ratio of mid to side (having a higher ratio of side).
Very strange desire, by reducing the mid fig 8 gain you will get a hole in the middle. Take it to its limits, you just get a two side mic pickups out of phase.

Quote:
This is similar to making the angle of the two mics in a Blumlein array further apart than 90°
Giving much more out of phase pickup.

Why one would ever want to decrease the relative gain of MS Blumlein mid is beyond me. Increase sure, but then just use a Cardioid mid. Gain changed MS Blumlein is not Blumlein.
Old 3 weeks ago
  #133
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I'm trying to clarify that an MS recording with a fig 8 mid is different from a Blumlein array, in that it does not have a fixed geometry. Similarly, if we adjust a Blumlein array by widening the angle, it is not a textbook Blumlein array. Although not a recommended practice to use on every recording, it would be close minded to insist that it should never be done. Some recordings can benefit from an artificially wide stereo image with the clear imaging of fig 8s.
Old 3 weeks ago
  #134
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Quote:
Originally Posted by aracu View Post
I'm trying to clarify that an MS recording with a fig 8 mid is different from a Blumlein array, in that it does not have a fixed geometry. Similarly, if we adjust a Blumlein array by widening the angle, it is not a textbook Blumlein array. Although not a recommended practice to use on every recording, it would be close minded to insist that it should never be done. Some recordings can benefit from an artificially wide stereo image with the clear imaging of fig 8s.
Fair enough. But I cannot ever imagine a need (that wouldn't be better served by another array config), unless perhaps a surround choir effect, or antiphonal brass or something.
Old 1 week ago
  #135
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Quote:
Originally Posted by David Spearritt View Post
Fair enough. But I cannot ever imagine a need (that wouldn't be better served by another array config), unless perhaps a surround choir effect, or antiphonal brass or something.
If you experimented with it in situations where the ensemble and / or acoustic needed to be enhanced artificially, you might end up feeling differently about it.

One thing I do tend to agree with you is that the term "Blumlein MS" is technically flawed, in that a Blumlein array is defined by a fixed geometry.

Another important difference between a Blumlein array and a mid-side array using a figure 8 mid, is that it allows for a particular version of the array by allowing the mid fig 8 and side fig 8 mics to be different from one another. The way to understand the value of this is through experimentation. I can sense the protests, but remember that a cardioid or omni mid mic can never possibly be matched with the side fig 8.
Old 1 week ago
  #136
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John Willett's Avatar
 

Question

Quote:
Originally Posted by aracu View Post
I can sense the protests, but remember that a cardioid or omni mid mic can never possibly be matched with the side fig 8.
Please explain, because I can't see your reasoning on this.
Old 1 week ago
  #137
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Yannick's Avatar
 

There’s a paper floating around which clearly proves that any mismatch between M and S mic actually gets dimished a lot when mixing the two to LR stereo.

So I do not get the comment as well, especially not for the MKH series which have been specifically designed for MS use with the MKH30.
Old 1 week ago
  #138
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Sorry for this swerve--I don't want to start a new thread for this--but for the life of me I cannot find the photos illustrating Rolo's and/or others' setups using two MKH 30s in MS. The photos on the first page by the OP don't seem to be the same type of setup, if I recall correctly.

I know I've seen them. Searched. Can't find them.

Does anyone have a few handy?
Old 1 week ago
  #139
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Here's some
Roger
Attached Thumbnails
MKH 30 / 30 MS imaging-dsc_0004.jpg   MKH 30 / 30 MS imaging-dsc_0002.jpg  
Old 1 week ago
  #140
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Quote:
Originally Posted by Rolo 46 View Post
Here's some
Roger
Lovely! Thank you!
Old 1 week ago
  #141
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Hey Roger.

Do you have any worries about the blockage to the rear of the mid MKH30 by the side MKH30? Would it be better, or worse, to mount the side MKH30 above the mid MKH30 is a standard "Blumlein" array turned to be M/S?

Sincere question, not poking.

And you have probably explained this somewhere that I just didn't see.

D.
Old 1 week ago
  #142
Gear Addict
I doubt that the shadowing is significant but just in case I use a Shapeways nose to nose mount for MS or XY with MKH30's.

https://www.shapeways.com/product/26...ionId=63166967

For XY Blumlein the mic clip/mount is right
behind the mics. For MS just rotate the
mic mount 45deg to the left. In either
case the mic mount and mic stand are 45 deg off-axis from the mics to minimize
shadowing.

Like my other Shapeways mounts I find it quick and easy.
Strongly recommend using it with a Rycote INV7 HG MKIII lyre mount.
This mount also works well with my
Shapeways MKH8040 ORTF and XY mounts.

Last edited by Folkie; 1 week ago at 07:01 AM..
Old 1 week ago
  #143
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Quote:
Originally Posted by tourtelot View Post
Hey Roger.

Do you have any worries about the blockage to the rear of the mid MKH30 by the side MKH30? Would it be better, or worse, to mount the side MKH30 above the mid MKH30 is a standard "Blumlein" array turned to be M/S?

Sincere question, not poking.

And you have probably explained this somewhere that I just didn't see.

D.
Doug ,we have been through this many, many times
Vertical mounting is visually obtrusive
Side by side or fore and aft are much more compact and shadowing is not an issue
Aiming the vertical array down causes as much non coincidence as the side or rear placement
They all sound the same to me anyhow...
Roger
Old 1 week ago
  #144
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tourtelot's Avatar
Yeah, okay. Just hadn't paid attention before this. It is not an array I use as a rule, the exception being sometimes using the Samar stereo ribbon, which, of course, is a stacked Blumlein. And sight-line problems? Maybe if it's a foot over the conductors head but don't you think that a 12' high mic stand is a bit more impactful? Just sayin'

But good to know that shadowing is minimal.

Thanks for the clarification and I'll sit in the front row from here on out as to not fall asleep in class. I think it's because my mom makes me eat these large breakfasts on school mornings and I hate the crash from Red Bulls.

BTW, I have a bunch of Shapeway mounts, especially OFTF that make the setup of that array quick and easy. I also recommend them highly, although it does take some ingenuity to mount them to stands sometimes.

D.
Old 1 week ago
  #145
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Larry Elliott's Avatar
Quote:
Originally Posted by tourtelot View Post

BTW, I have a bunch of Shapeway mounts, especially OFTF that make the setup of that array quick and easy. I also recommend them highly, although it does take some ingenuity to mount them to stands sometimes.

D.
I agree finding a way of mounting them can be "challenging"
Old 1 week ago
  #146
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mount to stand?

Quote:
Originally Posted by Folkie View Post
I doubt that the shadowing is significant but just in case I use a Shapeways nose to nose mount for MS or XY with MKH30's.

https://www.shapeways.com/product/26...ionId=63166967

For XY Blumlein the mic clip/mount is right
behind the mics. For MS just rotate the
mic mount 45deg to the left. In either
case the mic mount and mic stand are 45 deg off-axis from the mics to minimize
shadowing.

Like my other Shapeways mounts I find it quick and easy.
Strongly recommend using it with a Rycote INV7 HG MKIII lyre mount.
This mount also works well with my
Shapeways MKH8040 ORTF and XY mounts.
Your information-rich post has my pair of MKH30 calling for this mount!



I can't see how to interface/mount the plastic cross bar covered by a plastic sleeve to a conventional stand, though.

Custom clamp needed?

TIA
Old 1 week ago
  #147
Gear Addict
Quote:
Originally Posted by Larry Elliott View Post
I agree finding a way of mounting them can be "challenging"
I find the Shapeways mounts very easy to use. As I mentioned above,
it is easy if you use a Rycote INV7 HG MKIII lyre mount to hold the Shapeways mount.
Below are pictures of the Shapeways MKH30 MS/Blumlein V4 mount held by the Rycote mount directly attached to a stand, with the Rycote mount attached to a
side-arm mic bar, and the Shapeways MKH8040 ORTF mount held by the same Rycote mount. Use of the side arm micbar allows for additional up/down angling (e.g. you can attach the side-arm mic bar upside down (thread pointed down) which will allow more downward tilting of the stereo mount.)

Feel free to contact me with questions.

Thanks,
Bill
Attached Thumbnails
MKH 30 / 30 MS imaging-img-4474.jpg   MKH 30 / 30 MS imaging-img-4476.jpg   MKH 30 / 30 MS imaging-img-4477.jpg  
Old 1 week ago
  #148
Gear Addict
The Rycote INV-7 HG MKIII mount (along with Rycote back-to-back clips) is also very useful for other MS setups with MKH30 side mic.

Photos below are MKH8040-cardiod/MKH30 and Josephson C617 (omni)/MKH30 MS setups. Would expect it to also work with e.g MKH40/MKH30, etc. pairs.
Attached Thumbnails
MKH 30 / 30 MS imaging-img-4479.jpg   MKH 30 / 30 MS imaging-img-4480.jpg  
Old 6 days ago
  #149
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tourtelot's Avatar
I agree; I have obviously found various ways to make the Shapeway mounts work, and I do love them. The Rycote suspension you show has proven good in a number of mounts.

D.
Old 6 days ago
  #150
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Larry Elliott's Avatar
Quote:
Originally Posted by Folkie View Post
I find the Shapeways mounts very easy to use. As I mentioned above,
it is easy if you use a Rycote INV7 HG MKIII lyre mount to hold the Shapeways mount.
Below are pictures of the Shapeways MKH30 MS/Blumlein V4 mount held by the Rycote mount directly attached to a stand, with the Rycote mount attached to a
side-arm mic bar, and the Shapeways MKH8040 ORTF mount held by the same Rycote mount. Use of the side arm micbar allows for additional up/down angling (e.g. you can attach the side-arm mic bar upside down (thread pointed down) which will allow more downward tilting of the stereo mount.)

Feel free to contact me with questions.

Thanks,
Bill
Thank you very much Bill. I will check the Rycote availability.

Larry
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