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MS tips/techniques for (field) recording
Old 24th May 2017
  #1
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MS tips/techniques for (field) recording

I am new to M/S recording (or recording in general if I may be humble) and I wondered if some of you could share tips and techniques for M/S field recording. I'm beginning to record sound effects, ambience, nature (as well as live gigs sometimes).

For instance, I understand that you need to duplicate the figure-of-8 signal and inverse its polarity to get true stereo from M/S. However, using the MixPre-3 as my mixer/digital recorder, the matrix stage would necessarily come later, at home, in production so to speak. So I wonder how you can trust/guide your ears with the placing of your microphones since you're actually not hearing the final recording.

Any piece of advice will be useful

Cheers from Spain!
Old 24th May 2017
  #2
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Quote:
Originally Posted by Octave Octavio View Post
I am new to M/S recording (or recording in general if I may be humble) and I wondered if some of you could share tips and techniques for M/S field recording. I'm beginning to record sound effects, ambience, nature (as well as live gigs sometimes).

For instance, I understand that you need to duplicate the figure-of-8 signal and inverse its polarity to get true stereo from M/S. However, using the MixPre-3 as my mixer/digital recorder, the matrix stage would necessarily come later, at home, in production so to speak. So I wonder how you can trust/guide your ears with the placing of your microphones since you're actually not hearing the final recording.

Any piece of advice will be useful

Cheers from Spain!
The MP3 has an MS matrix for the HP-out so you can hear XY while recording MS.
Old 24th May 2017
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Old 24th May 2017
  #4
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Quote:
Originally Posted by Octave Octavio View Post
Are you sure ?

Doesn't have Input Polarity Reverse according to SD website https://www.sounddevices.com/product...ure-comparison
The HP-selector has an MS to XY option so you can record discrete MS to your tracks but what you hear is XY(L/R-Stereo).

Or you can chose to record directly to XY from your MS-mic. (MS-linking option).

What you describe is how to turn MS into XY using a traditional mixer or the equivalent in the ProTools mixer.

No need to set that up from scratch on the MP. Like you said, you're doing that in post not on the machine.

Last edited by apple-q; 24th May 2017 at 05:09 PM..
Old 30th May 2017
  #5
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Here's a screen-shot of the mid-side headphone preset I have set up on my Mixpre-3 for monitoring the decoded/matrixed MS while recording the original M and S mics to channels 1 and 2 respectively. You can see the MS box in the bottom right that you need to check. The manual is a bit hazy in this regard, and I hope SD add such detail in due course.

Cheers,

Roland
Attached Thumbnails
MS tips/techniques for (field) recording-_2690095.jpg  
Old 30th May 2017
  #6
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Octavio: I wanted to help clarify this. You will want to record the mid and side signals as they are, directly off the mics. Then with your digital audio workstation, decode those two tracks into stereo. You generally have the right idea about decoding the mid and side tracks to stereo, but let me add:

When tracking:
-- Make sure that the in-phase side of your figure-8 mic faces what will be left in your stereo field.
-- If you are using a figure-8 for the mid mic, the in-phase side should be facing forward, otherwise it's just your cardioid facing forward.
-- Roger puts a little red dot sticker on the +phase sides of his mics. It's a helpful idea when working in dim lighting while rushed.

The MixPre3 will allow you to monitor a mid side mic array in stereo. I believe they call this "MS Linking". The thing to be careful about on SD recorders is that the recorders give you the option of recording either the decoded stereo signal, or the raw mid and side signals. By default, the SD788, for example, records the decoded stereo signal. But by changing the setup menu item: "MS to Pre-Fade ISO" to the OFF setting, the recorder will capture the discrete mid and side signals. I wanted to point this out to you and make it clear, but I was once bitten by this feature when I ended up recording the decoded stereo signal by accident. This "MS to Pre-Fade ISO" thing wasn't really very intuitive to me because I have always been using the Nagra VI, which ALWAYS records the mid and side signals, NEVER the decoded stereo signal, unless you route the decoded signal to the mix tracks. But with the Nagra, you ALWAYS have the raw mid and side. The SD recorders offer either way, but you have to be careful to make sure that MS to Pre-Fade setting is OFF.

Again, your recorder will allow you to monitor in stereo, so there is no "trusting your ears" or learning some special technique to monitor mid-side. Your SD recorder will give you decoded stereo to your headphones.

In post:
-- Duplicate the side channel
-- Flip the phase of the duplicate channel
-- Pan the duplicate side channel hard right
-- Pan the original side channel hard left
-- Vary the ratio of the mid to the side channels to adjust stereo width

Hope that helps and glad to see your interest in mid side.

Quote:
Originally Posted by Octave Octavio View Post
I am new to M/S recording (or recording in general if I may be humble) and I wondered if some of you could share tips and techniques for M/S field recording. I'm beginning to record sound effects, ambience, nature (as well as live gigs sometimes).

For instance, I understand that you need to duplicate the figure-of-8 signal and inverse its polarity to get true stereo from M/S. However, using the MixPre-3 as my mixer/digital recorder, the matrix stage would necessarily come later, at home, in production so to speak. So I wonder how you can trust/guide your ears with the placing of your microphones since you're actually not hearing the final recording.

Any piece of advice will be useful

Cheers from Spain!
Old 31st May 2017
  #7
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Be careful when using MS.... by increasing the width of MS either by increasing S+ & S- or by reducing the M signal you are actually altering the Mono compatibility of the mix.

Always, Always cross check you mix in Mono.... A mix done with a MS signal in it can be stuffed up easily. (been there done that)
Old 31st May 2017
  #8
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Quote:
Originally Posted by OzGizmo View Post
Be careful when using MS.... by increasing the width of MS either by increasing S+ & S- or by reducing the M signal you are actually altering the Mono compatibility of the mix.
How does it alter the mono compatibility? The sides will cancel out regardless of their proportion to the mid. You'll be left with just the mid signal. Same as if the side mic were never there.
Old 31st May 2017
  #9
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Quote:
Originally Posted by leddy View Post
How does it alter the mono compatibility? The sides will cancel out regardless of their proportion to the mid. You'll be left with just the mid signal. Same as if the side mic were never there.
During mixing, the sides will only null successfully if the S+ and S- are in equal proportion to one another...anything other than that and the Side component could be expected to add 'weirdness' to the mix ? The Mid is simply pure mono, so it's inherently compatible per se ?
Old 31st May 2017
  #10
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Try it...... Push the sides of MS in a mix and Mono it and listen to what happens....... Drums, atmos Fx, piano anything

Do it in real time don't just hypothesis over it.... Do It

This is the stuff Ive been playing with for nearly 40 years of Broadcast TV sound.

Last edited by OzGizmo; 31st May 2017 at 07:29 AM..
Old 31st May 2017
  #11
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Quote:
Originally Posted by bwanajim View Post
The MixPre3 will allow you to monitor a mid side mic array in stereo. I believe they call this "MS Linking". The thing to be careful about on SD recorders is that the recorders give you the option of recording either the decoded stereo signal, or the raw mid and side signals. By default, the SD788, for example, records the decoded stereo signal. But by changing the setup menu item: "MS to Pre-Fade ISO" to the OFF setting, the recorder will capture the discrete mid and side signals. I wanted to point this out to you and make it clear, but I was once bitten by this feature when I ended up recording the decoded stereo signal by accident. This "MS to Pre-Fade ISO" thing wasn't really very intuitive to me because I have always been using the Nagra VI, which ALWAYS records the mid and side signals, NEVER the decoded stereo signal, unless you route the decoded signal to the mix tracks. But with the Nagra, you ALWAYS have the raw mid and side. The SD recorders offer either way, but you have to be careful to make sure that MS to Pre-Fade setting is OFF.
This advice doesn't apply to the Mixpre-3, I'm afraid: MS linking (push channel 1 knob to access this) on the Mixpre-3 means recording the decoded (encoded?) MS signal - i.e. recording LR stereo. Recording the raw M and S signals whilst monitoring in stereo to headphones means record as normal (i.e. do not apply MS linking), but set up a headphone preset as per my previous post and screenshot (i.e. post number 5).

Cheers,

Roland
Old 31st May 2017
  #12
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Quote:
Originally Posted by bwanajim View Post
Octavio: I wanted to help clarify this. You will want to record the mid and side signals as they are, directly off the mics. Then with your digital audio workstation, decode those two tracks into stereo. You generally have the right idea about decoding the mid and side tracks to stereo, but let me add:

When tracking:
-- Make sure that the in-phase side of your figure-8 mic faces what will be left in your stereo field.
-- If you are using a figure-8 for the mid mic, the in-phase side should be facing forward, otherwise it's just your cardioid facing forward.
-- Roger puts a little red dot sticker on the +phase sides of his mics. It's a helpful idea when working in dim lighting while rushed.

The MixPre3 will allow you to monitor a mid side mic array in stereo. I believe they call this "MS Linking". The thing to be careful about on SD recorders is that the recorders give you the option of recording either the decoded stereo signal, or the raw mid and side signals. By default, the SD788, for example, records the decoded stereo signal. But by changing the setup menu item: "MS to Pre-Fade ISO" to the OFF setting, the recorder will capture the discrete mid and side signals. I wanted to point this out to you and make it clear, but I was once bitten by this feature when I ended up recording the decoded stereo signal by accident. This "MS to Pre-Fade ISO" thing wasn't really very intuitive to me because I have always been using the Nagra VI, which ALWAYS records the mid and side signals, NEVER the decoded stereo signal, unless you route the decoded signal to the mix tracks. But with the Nagra, you ALWAYS have the raw mid and side. The SD recorders offer either way, but you have to be careful to make sure that MS to Pre-Fade setting is OFF.
The 788 has MS-linking just like the MP3 and the 744 and the 702. No need to use the MS to pre-fade iso" you can record straight MS or decoded XY depending on the linking you chose. MS-Linking means it records XY. normal linking means the channels are just linked but not turned to XY prior to recording.

"MS to pre-fade ISO" feature is just for complex routing/mixdown setups.
Old 31st May 2017
  #13
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Quote:
Originally Posted by OzGizmo View Post
Try it...... Push the sides of MS in a mix and Mono it and listen to what happens....... Drums, atmos Fx, piano anything

Do it in real time don't just hypothesis over it.... Do It

This is the stuff Ive been playing with for nearly 40 years of Broadcast TV sound.
I record MS all the time. I just pulled up an MS recording. I hit the mono button on my monitor controller (so I folded in a stereo mix), then while listening I'd solo the mid channel and go back and forth. Couldn't hear a difference.

If I have time I'll take a stereo render, then reprocess to mono, then see if that nulls with just the mid channel of the same recording. My guess is it will. (Unless the sides are not equal as Studer said).

Edit:
I just did it quick and they nulled.
Old 31st May 2017
  #14
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Quote:
Originally Posted by leddy View Post
I record MS all the time. I just pulled up an MS recording. I hit the mono button on my monitor controller (so I folded in a stereo mix), then while listening I'd solo the mid channel and go back and forth. Couldn't hear a difference.

If I have time I'll take a stereo render, then reprocess to mono, then see if that nulls with just the mid channel of the same recording. My guess is it will. (Unless the sides are not equal as Studer said).

Edit:
I just did it quick and they nulled.
Yes they always null. What Oz is saying that when you pull up your s you'll get more and more negative correlation in your resulting XY stereo signal which usually is flagged by QC. When summed it will obviously null away. Hence the red flag.

That said: that high S signal is obviously wrong as it is beyond the width that is achievable with MS anyway. Normal MS to XY decoding is perfectly fine and mono-compatible even by the correlation meter.

Technically an xy signal with very high S content will still be 100% mono-compatible but the result when summed is a very low M signal because most of your signal was +S and -S.

When Oz says "mono-compatible" I think he means it will sound more or less the same when played back on a mono TV/Radio which isn't the case when your S signal is higher than the M signal. The result will be much quieter but still the pure M signal.
Old 1st June 2017
  #15
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One of the main problems with MS is the step AFTER the actual recording, hey its easy enough to record a Mid signal on one track and a fig8 on the other...BUT what happens when you pass it to the next person in the production chain...Do they know how to take the raw MS material and make it into a usable / broadcast-able track?

Lets face it that most editors are so stressed in their process the last thing they want to deal with is some sort of 'coding' / audio trickery. They understand stereo music from CDs or other sources. Ok you can educate them over time if EVERY stereo tracked arrived in that sort of coding but they don't.
What do you do after about 10 years and 6 generations of staff changes?

I've been involved with Broadcast TV for 40+ years and thought that MS was the answer to stereo production for location but it actually created more problems than it solved, switched to XY and those problems / training required disappeared and the results are SO much better On Air.

I recommend ANY location sound person sit in on a post production session for a day or so (not just an hour) and see how work flows are actually used.

Look MS is a good system IF and ONLY If everybody in the production chain understands it, how to work with it..... IF not you have got problems.
Old 1st June 2017
  #16
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Quote:
Originally Posted by OzGizmo View Post
One of the main problems with MS is the step AFTER the actual recording, hey its easy enough to record a Mid signal on one track and a fig8 on the other...BUT what happens when you pass it to the next person in the production chain...Do they know how to take the raw MS material and make it into a usable / broadcast-able track?

Lets face it that most editors are so stressed in their process the last thing they want to deal with is some sort of 'coding' / audio trickery. They understand stereo music from CDs or other sources. Ok you can educate them over time if EVERY stereo tracked arrived in that sort of coding but they don't.
What do you do after about 10 years and 6 generations of staff changes?

I've been involved with Broadcast TV for 40+ years and thought that MS was the answer to stereo production for location but it actually created more problems than it solved, switched to XY and those problems / training required disappeared and the results are SO much better On Air.

I recommend ANY location sound person sit in on a post production session for a day or so (not just an hour) and see how work flows are actually used.

Look MS is a good system IF and ONLY If everybody in the production chain understands it, how to work with it..... IF not you have got problems.
+1

If I'm recording stuff that I know only I am going to use, I'll record raw MS. If its getting passed to someone else for post, I'll go ahead and decode to stereo.

-Mike
Old 1st June 2017
  #17
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Unfortunately there a new generation of 'location sound people' coming through the world scene that seem to only record ISO tracks, have little knowledge of workflows other than the ones taught at film school and have little or no / little ability to mix live. Even mixing 2 lav mics to one track without 'auto mix' some people seem to struggle at.
Yes its all very nice to record ISO or raw MS and then hand it up to post production patting themselves on the back, but often they have just handed on their problems to someone further down the chain.
Old 4th June 2017
  #18
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I have read all these posts with great interest and I would like to ask how would you set up a configuration to record a violin and a baroque lute in a nice sounding room/small church if you only had 4 mics. (2 cardioids and 2 omnis) ?
Would you use both cardioids for the lute, to compensate for the soft volume and let the violin be capture by the omnis in AB, or would you rather use 1 cardioid for each instrument + the omnis as AB to capture the reverb of the place ?

Thank you
Herman
Old 5th June 2017
  #19
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Quote:
Originally Posted by Herman Heil View Post
I have read all these posts with great interest and I would like to ask how would you set up a configuration to record a violin and a baroque lute in a nice sounding room/small church if you only had 4 mics. (2 cardioids and 2 omnis) ?
Would you use both cardioids for the lute, to compensate for the soft volume and let the violin be capture by the omnis in AB, or would you rather use 1 cardioid for each instrument + the omnis as AB to capture the reverb of the place ?

Thank you
Herman
This thread is about M/S. So your question is not relevant in any way to the subject.

Perhaps start a new thread with your question.
Old 9th June 2017
  #20
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Great posts in the thread, thanks everyone for helping.
Old 10th June 2017
  #21
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The other night, I was recording a small concert and the organizer brought in someone he said had a lot of experience to do the FOH sound. He's also a musician with several folk albums to his credit. During setup and sound check, he was ogling my AKG C246 set up in M/S as a room mic. He though it very strange that one capsule faced forward, while the other faced to the sides. He looked at me askance as I explained that it was set up as a mid side array and that I had the forward facing capsule set to supercard, and the side capsule to fig8. He was pretty bewildered by the thing, and wanted to know how in the world you could get stereo out of it. So I said something like "Well, in your DAW, you keep the mid mic panned center, pan the in-phase side channel hard left, then make a copy, flip the phase and pan it hard right. Mix them all together at equal levels and you have stereo. If you set the mid mic to fig 8 as well and you have the equivalent of a standard Blumlein array. Then, you can adjust the stereo field by varying the proportion of the mid channel to the side channels." "Whoa, whoa, whoa", he said, "You just used way too many 50 cent words there!".

I think a lot of people just find M/S too geeky. This fellow was really surprised to learn about all the things you could do in post when you capture in M/S. He'd never even heard of it despite his years mixing FOH and even recording his own albums. It really is a shame more people don't take the time to learn this useful technique.
Old 11th June 2017
  #22
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Quote:
Originally Posted by bwanajim View Post
He'd never even heard of it despite his years mixing FOH and even recording his own albums. It really is a shame more people don't take the time to learn this useful technique.
M/S is just not used routinely (if at all) in the audio reinforcement side of FOH...perhaps it might be in the recording side of live concerts ? Ditto for recording studios, which typically use multi-track overdub methods for recording multiple instruments. Nothing in the typical small studio, with its damped walls and ceilings, invites any desire to capture or manipulate the non-existent 'acoustics' of the space.

Location movie and documentary sound, and radio...that is the true domain of M/S. There, I'd be surprised to find practitioners who aren't aware of it, or don't use it regularly.
Old 12th June 2017
  #23
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If you are doing anything in 5.1 then MS has big problems....
Old 20th June 2017
  #24
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Thread Starter
Would it be weird to do m/s studio and/or field recording with Gefell mics ?

MV692 M94 for cardioid + MV692 UM70 for fig of eight
Old 24th June 2017
  #25
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Quote:
Originally Posted by OzGizmo View Post
If you are doing anything in 5.1 then MS has big problems....
Why ?
Old 24th June 2017
  #26
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I've used MS in 5.1 without problems.
Old 24th June 2017
  #27
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Quote:
Originally Posted by Yannick View Post
Why ?
As MS stereo is a 'phase' based stereo using both + and - of the side signal it appears that the conversion from 6 discreet channel program mix (5.1) Dolby Surround to a 2 channel encoded system to sent it to a Transmitter via a STL and then converting it back to 5.1 in the home receiver / monitoring some strange things happen in the L & R surround.

Some of the things that I noticed was some off shoots from Front R were appearing in L rear and the reverse, some Front L signals are appearing in R rear.

If you listen at the mixer its seems to be ok but it seems the encoding / decoding maybe part of the problem.

This happened at a stadium sporting event on a TV outside broadcast, the following week the MS mic (VP88) was changed to an AKG 552 stereo XY mic, the odd phasing oddities this week didn't seem to appear the rest of the mics and positions were virtually the same.

Ok yes it could have been some other thing but in a tight time lines of broadcasting you need systems that work, and work well EVERY time.
If like most productions you only have about 3-4 hrs from arrival to airtime you can't afford spending an hour or so on getting your crowd sound in 5.1 right.

Im currently looking at the new Sennheiser surround mic, its work flow is and could it be a better option than the setups we currently have.

Ok if you have the time and ability to change things in a post production studio it might be ok, but I just can't be bothered anymore.
Old 24th June 2017
  #28
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Interesting, but that's a very specific broadcast transmission issue, and not a general problem with MS and surround.
Old 24th June 2017
  #29
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This depends on the mid mic pattern IMO.

And the encoding/decording to stereo.

Purely for 5.1 double ms works great.
Old 24th June 2017
  #30
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Quote:
Originally Posted by itsyourself View Post
Interesting, but that's a very specific broadcast transmission issue, and not a general problem with MS and surround.
Yes while that is true.... Even a feature film will one day end up being sent in a transmission system.

I can recall a conversation I had with a film mixer about wide MS, he claimed it was fine and not a problem......UNTILL i got a copy of that film on DVD and played it back to him in mono high lighting the problems that it contained for broadcast.... 20+ years after the film was released.

While a sound mix that works well for one situation may not work well in another, just keep in mind that often product WILL end up in a different format.

And this is why products like this exist https://www.youtube.com/watch?v=hujVyCXqjPw
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