Topic: Mid-side panning question.

[chinariderstl]

Hi, I am just now getting into mid-side recording and have a couple questions about panning the mics.  I will be using a cardioid and a figure-eight mic.

1. How should I pan the cardioid on my pre-amp (Mixpre) and/or deck (DR-680)?  Middle?
2. How should I pan the figure-eight mic (on the Mixpre/DR-680)?  Left?

I'll be doing post in either Audacity or Sound Forge.

I appreciate any input.

Thanks, Chris.

[page]

When recording, keep the channels separate (Cardioid/Forward in the left channel, the figure 8 in the right). Do your M/S decoding in post, you're giving up one of it's greatest features by trying to do it in the field.

[chinariderstl]

Right, record to two mono tracks and decode in post.  (I guess that eliminates the Mixpre > PCM-M10 option, because I don't think the M10 can record to two mono tracks.  I think it only records a stereo pair.  I could be wrong, though.)

So, on the DR-680, should I pan the mics?  From what I've read, it seems like I would pan the card Center (or no panning), and pan the figure-eight to the Left.  (Then duplicate the left track to the right channel in post).

Sorry if these questions seem remedial.

[mec111272]

http://www.youtube.com/watch?v=nFiIJAIKN0o

 I did my first attempt last week.  Used this as a quick guide. 

[voltronic]

Right, record to two mono tracks and decode in post.  (I guess that eliminates the Mixpre > PCM-M10 option, because I don't think the M10 can record to two mono tracks.  I think it only records a stereo pair.  I could be wrong, though.)

So, on the DR-680, should I pan the mics?  From what I've read, it seems like I would pan the card Center (or no panning), and pan the figure-eight to the Left.  (Then duplicate the left track to the right channel in post).

Sorry if these questions seem remedial.

EDIT: You can certainly use your MixPre.  Pan the fig 8 channel right and the center card left.  You could do the opposite if doing a matrix yourself as described here, but I believe mid/side processing plugins would expect that mid is left and side is right.  The most important thing is you remember which was which.  Then those two mics will appear in those respective channels in your recorded tracks.
Record everything center-panned to avoid confusion later.

The M10 records as a stereo track, but it's not a problem.  If you import your mid-side track into Audacity, click the drop-down on the track menu and select "split stereo to mono".  Note that this is different than the normal "split stereo track" choice because if you did it that way, you'd then need to go into each of the resulting two tracks and change them from Left or Right to Mono.

Label your MID and SIDE before going on.  It's easy to tell by listening if you forgot - mid is no room sound; side is only the room.  Now make a duplicate of the Side channel.  Pan the first one hard-left.  Pan the second one hard-right, and then invert its phase.  In Audacity, you have to do this by selecting that entire track, and then using Effect > Invert.  In SoundForge there should be a similar function.  Other DAWs usually have a switch right on the channel to do this.

Then you can play with your stereo image by lowering the level of the two Side tracks until you get the balance you want.  Leave the Mid (cardioid track) alone.  Just make sure you're moving the two side tracks by equal amounts - I don't think there's a way to link track faders in Audacity like you can in other programs.

[voltronic]

http://www.youtube.com/watch?v=nFiIJAIKN0o

 I did my first attempt last week.  Used this as a quick guide.

That video shows how to make a standard L/R stereo recording into mid-side channels.  chinariderstl is trying to do the opposite.

[chinariderstl]

Right, record to two mono tracks and decode in post.  (I guess that eliminates the Mixpre > PCM-M10 option, because I don't think the M10 can record to two mono tracks.  I think it only records a stereo pair.  I could be wrong, though.)

So, on the DR-680, should I pan the mics?  From what I've read, it seems like I would pan the card Center (or no panning), and pan the figure-eight to the Left.  (Then duplicate the left track to the right channel in post).

Sorry if these questions seem remedial.

Record everything center-panned to avoid confusion later.

The M10 records as a stereo track, but it's not a problem.  If you import your mid-side track into Audacity, click the drop-down on the track menu and select "split stereo to mono".  Note that this is different than the normal "split stereo track" choice because if you did it that way, you'd then need to go into each of the resulting two tracks and change them from Left or Right to Mono.

Label your MID and SIDE before going on.  It's easy to tell by listening if you forgot - mid is no room sound; side is only the room.  Now make a duplicate of the Side channel.  Pan the first one hard-left.  Pan the second one hard-right, and then invert its phase.  In Audacity, you have to do this by selecting that entire track, and then using Effect > Invert.  In SoundForge there should be a similar function.  Other DAWs usually have a switch right on the channel to do this.

Then you can play with your stereo image by lowering the level of the two Side tracks until you get the balance you want.  Leave the Mid (cardioid track) alone.  Just make sure you're moving the two side tracks by equal amounts - I don't think there's a way to link track faders in Audacity like you can in other programs.

This is killer, thank you for the detailed instructions.

I am going to practice with my Avantone CK-40.

[Tom McCreadie]

With the M and S channel signals panned hard left and right, just record it as a conventional stereo file, then in post run that file through the free Voxengo MSED plugin.

[page]

With the M and S channel signals panned hard left and right, just record it as a conventional stereo file

This. Treat the channels just like a normal stereo pair, you don't want any of the left channel signal in the right channel and vice versa while recording. It doesn't matter whether you're doing M/S or a standard stereo pair. With M/S you just do the decode to normal stereo later in your DAW.

[chinariderstl]

Sounds good, thanks guys.  I really appreciate the input!

I'll run some tests at home and see how it goes.

Chris.

[microburst]

With the M and S channel signals panned hard left and right, just record it as a conventional stereo file, then in post run that file through the free Voxengo MSED plugin.

^^^^ This...is the easiest fail safe solution.  I also highly recommend Voxengo MSED...it's super easy to use.

I've also found that the Mid-Side Mic Visualizer iPhone app (https://itunes.apple.com/us/app/mid-side-mic-visualizer/id486145346?mt=8) is a great tool for getting angle/width and pattern approximations while obviously using your ears to fine tune the M/S matrix in post.  It costs a buck but what can you buy in the real world for under a $1 these days?

[tgakidis]

All this talk of mid side is making me want to run that tonight for Club d'Elf in cambridge 

[microburst]

Do it Ted...never ran M/S at the Lizard when I lived in Boston but did a few Blumlein recording with a pair of TLM 170's at d'Elf shows.  I found it a good room to expreiment, especially when more and more tapers caught on to d'Elf.  Seems all their shows get captured now.  I'm hoping to make it up to their show in Marlboro, NY on 10/30 with Medeski.

In terms of M/S recordings, I haven't made any since Janaury but last week finally got around to decoding a good chunk of my M/S recordings frm Jam Cruise.  The post work got me motivated to do some more M/S captures before the year is out. 

[MIQ]

With the M and S channel signals panned hard left and right, just record it as a conventional stereo file, then in post run that file through the free Voxengo MSED plugin.

^^^^ This...is the easiest fail safe solution.  I also highly recommend Voxengo MSED...it's super easy to use.

I've also found that the Mid-Side Mic Visualizer iPhone app (https://itunes.apple.com/us/app/mid-side-mic-visualizer/id486145346?mt=8) is a great tool for getting angle/width and pattern approximations while obviously using your ears to fine tune the M/S matrix in post.  It costs a buck but what can you buy in the real world for under a $1 these days?

+T for the Voxengo MSED plug.  Easy to use and works well. 

Another free but more complicated VST tool is the Flux Stereo Tool  http://www.fluxhome.com/products/freewares/stereotool  It is not labeled as a Mid Side processor but the "Width" control is doing just that.  It converts from L&R to M&S (sum and difference) then allows you to alter the ratio of Mid to Side then converts back to L&R (sum and difference) at the output.  That's different than what you want to do but I thought I'd mention it.  It has a cool vector scope visual display that lets you see the level and phase relationships of the audio signals that are being fed throught its processing which is cool even if you never touch the "width" control.  The scope is a modern day version of the AEA LD2020 Stereo Scope.  http://www.posthorn.com/Aea_5.html  Wes Dooley knows a thing or two about MS.   

Thanks for the props on the MS Visualizer microburst!  Glad to hear you are a happy user.

Miq

[capnhook]

I use the Voxengo MSED plug-in for going the other way, from XY@90 to Mid-Side.

It's like a pair of good channel-locks......something everyone should have.

[page]

I must be the only person who does the decoding by hand...

[tgakidis]

Do it Ted...never ran M/S at the Lizard when I lived in Boston but did a few Blumlein recording with a pair of TLM 170's at d'Elf shows.  I found it a good room to expreiment, especially when more and more tapers caught on to d'Elf.  Seems all their shows get captured now.  I'm hoping to make it up to their show in Marlboro, NY on 10/30 with Medeski.

In terms of M/S recordings, I haven't made any since Janaury but last week finally got around to decoding a good chunk of my M/S recordings frm Jam Cruise.  The post work got me motivated to do some more M/S captures before the year is out.

https://archive.org/details/delf2014-10-17.akg414.mid-side.flac

[Gutbucket]

Just to clarify, when recording to the 6 primary input channels of the DR-680 there is no input panning available.  The only channel panning available is through the monitor (output) mix.  You can set things up to record that monitor output mix to the stereo channel in addition to recording the direct individual inputs, and that is the only way to record a panned input channel.  Even then you'd still have the unpanned input channels recorded as well.

Playing back files directly from the DR-680 through the monitor mix instead of as individual channel outs, you can do M/S to L/R matrixing on channel pairs, which provides width control but no panning.

You can probably set up the DR-680 to record the L/R output after it's internal M/S matrix.  I've never done that, and like the other have suggested, it's usually better to record the independent M and S channels separately, but even in that case there is no pan control, only a width control.

[kindms]

I must be the only person who does the decoding by hand...

I do it that way as well. It took a few tries to get the process down in audacity but Now I always do it that way.

[DSatz]

Um, voltronic--if I'm reading your advice correctly, it would cause both channels on the recorder to contain the signals from both microphones in equal amounts. That would give you the left channel of the intended stereo pickup in both recorded channels, while the right channel would be lost and unrecoverable.

If a person has already made up their mind to produce the stereo L/R version of an M/S recording in post, they should simply record the M microphone's signal on the left track (i.e. panned all the way to left if that's an issue) and the S microphone's signal on the right track (all the way to the right). No mixing or combining of signals should occur until the person is ready to make their choices while listening to the results.

There's no question that matrixing in post gives optimal results much more reliably, since with two-microphone M/S, there's usually only one relative gain setting between M and S signals that sounds right at all (i.e. has a reverberation balance that plausibly matches the width of the stereo image)--and in my experience, it's not usually the setting that you'd get by coincidence. Just because a person ignores an issue doesn't make that issue go away. Mother Nature doesn't reward us for ignoring the inherent difference in sensitivity between M and S microphones (why should two different models of microphone or capsule have identical 0° sensitivity? Usually they don't) and the difference in gain between your two recorder channels (analog level controls can easily cause 1 to 2 dB differences between channels). With some practice you can get the live recording to be "in the ballpark" but it nearly always sounds better when you choose the relative gain setting by ear, i.e. by matrixing in post while monitoring the L/R result. And that approach also lets you do nice things such as boosting the low frequencies of the "S" channel before converting to L/R stereo.

--best regards

P.S.: Originally I mistyped the last sentence and wrote "M" channel instead. Sorry!

[voltronic]

Um, voltronic--if I'm reading your advice correctly, it would cause both channels on the recorder to contain the signals from both microphones in equal amounts. That would give you the left channel of the intended stereo pickup in both recorded channels, while the right channel would be lost and unrecoverable.

If a person has already made up their mind to produce the stereo L/R version of an M/S recording in post, they should simply record the M microphone's signal on the left track (i.e. panned all the way to left if that's an issue) and the S microphone's signal on the right track (all the way to the right). No mixing or combining of signals should occur until the person is ready to make their choices while listening to the results.

There's no question that matrixing in post gives optimal results much more reliably, since with two-microphone M/S, there's usually only one relative gain setting between M and S signals that sounds right at all (i.e. has a reverberation balance that plausibly matches the width of the stereo image)--and in my experience, it's not usually the setting that you'd get by coincidence. Just because a person ignores an issue doesn't make that issue go away. Mother Nature doesn't reward us for ignoring the inherent difference in sensitivity between M and S microphones (why should two different models of microphone or capsule have identical 0° sensitivity? Usually they don't) and the difference in gain between your two recorder channels (analog level controls can easily cause 1 to 2 dB differences between channels). With some practice you can get the live recording to be "in the ballpark" but it nearly always sounds better when you choose the relative gain setting by ear, i.e. by matrixing in post while monitoring the L/R result. And that approach also lets you do nice things such as boosting the low frequencies of the "M" channel before converting to L/R stereo.

--best regards

DSatz,

With respect, I'm not sure how you are interpreting what I wrote in that way.  The M10 generates a stereo track, one channel of which would be your mid and the other the side.  It is necessary to split them into two separate tracks in software to duplicate the side track and do normal mid side balancing, etc.  Unless one were to use a preamp with mixing capabilities, mid/side or otherwise, I don't see how it would be possible for either of the two mic signals to be recorded in duplicate channels as you are suggesting. 

In any case, we are in complete agreement about matrixing in post for the exact reasons you state.

[Tom McCreadie]

Um, voltronic--if I'm reading your advice correctly, it would cause both channels on the recorder to contain the signals from both microphones in equal amounts. That would give you the left channel of the intended stereo pickup in both recorded channels, while the right channel would be lost and unrecoverable.

Yes, Voltronic's' opening statement:  "Record everything center-panned to avoid confusion later." is incorrect and causes confusion itself  :-).  It seems to contradict his subsequent correct explanation in the same post. '

... With some practice you can get the live recording to be "in the ballpark" but it nearly always sounds better when you choose the relative gain setting by ear, i.e. by matrixing in post while monitoring the L/R result. And that approach also lets you do nice things such as boosting the low frequencies of the "M" channel before converting to L/R stereo.

Actually it's often the boosting of the low frequencies in the "S" channel that does the nice things!
For this increases the perceived width of the bass sound sources (which tend to image too centrally), so that they then fall into better lateral register with their higher frequency brethren. Something like a bass boost of ca. 2-3db between 300 and 700 Hz. Gerzon and Griesinger worked on this in the 80's and 90's, with descriptions like "shuffling" and "spatial equalization".

Confusingly  :-), the term "shuffling" has morphed in meaning: I believe it was first coined by Blumlein to describe a different operation - comandeering two closely-spaced omni capsules (N.B.  _not_ back-to-back coincident cardioids) to synthesize a Fig8 pattern for his research. My understanding is that Gerzon's work is what's been implemented in the Waves "S1 Shuffler" plugin.

[voltronic]

Um, voltronic--if I'm reading your advice correctly, it would cause both channels on the recorder to contain the signals from both microphones in equal amounts. That would give you the left channel of the intended stereo pickup in both recorded channels, while the right channel would be lost and unrecoverable.

Yes, Voltronic's' opening statement:  "Record everything center-panned to avoid confusion later." is incorrect and causes confusion itself  :-).  It seems to contradict his subsequent correct explanation in the same post. '

How is this incorrect?  For a "regular" 2-channel stereo recording, I agree that would certainly be wrong to do it that way.  Maybe I'm having trouble processing this - how does the panning of two separate recorded tracks at the time of recording makes any difference if you are going to run them through a mid-side matrix later on?  If the recorder is recording them as two separate mono tracks then it shouldn't be an issue and you're going to alter the panning in post anyway.  For instance, why would one ever choose to record the side track panned left and the mid track panned right, unless you are recording through a mid-side matrix and then into your recorder?  Once in the DAW, you're going to have the center track panned center in your matrix anyway so why pan it otherwise in the first place?

Granted I've never used the DR-60, so maybe I don't have a full understanding of its controls.  I've only ever done mid/side recordings going from the preamp into the M10 or a Zoom H6, and the panning is not adjustable on those.

[Gutbucket]

It all depends on when the panning happens- in the signal chain prior to the signals being recorded, in a live monitor mix during the recording although not recorded itself, afterwards on playback from the machine or in the DAW.

[Life In Rewind]

I guess the lingo depends on your recorder's features and how you have it setup - 2 channel recorders vs multichannel with mix functions
Some record multiple mono wav files - no panning needed during mastering,
Some might also record a single wav with 2 channels that are already in effect, panned...

Your really just mastering two mono sources.

[DSatz]

voltronic, I really don't see where the ambiguity could be. When recording M/S for the purpose of matrixing to L/R stereo afterward, you send the M microphone's signal to the recorder's left-channel input and the S microphone's signal to the recorder's right-channel input. If the microphones are connected to a preamp or mixer that has pan controls, you would pan the M signal fully to the left and the S signal fully to the right.

Your advice was, "Record everything center-panned to avoid confusion later." But center panning, for a mixer or preamp that has two output channels, means directing an input signal to the L and R outputs with equal amplitude. Thus what you wrote is equivalent to saying, "Record 50% M plus 50% S in both recorder channels."

I'm glad that isn't what you meant to say. And it's very nice to see Mahler's picture next to your posts.

--best regards

P.S.: Tom McC, you're right--that was a typo when I talked about boosting the bass in the "M" channel. And it's even a typo I've made at least once before. (Sheesh.)

[voltronic]

DSatz,

OK, now I see where you're coming from.  While I understand that center panning a channel in a mixing console will send the signal equally to the left and right mains, for some reason I didn't think standalone digital recorders are structured in that way internally.  Now I realize it makes sense that those devices would do the same thing.  I'll edit my original post to reflect this.

Thanks for noticing our friend Gustav.  You are now the second one here to call him out.

[Tom McCreadie]

Thanks for noticing our friend Gustav.  You are now the second one here to call him out.

Overheard years ago on a London tube escalator: "Gustav Mahler is in grave danger of being taken too seriously."   :-)

[chinariderstl]

Thanks again guys.  I just sent my stock Avantone CK-40 LD stereo mic to Chris Johnson at Busman Audio to have it upgraded to the "BSCS-L sound."  I am anxious to try my hand at mid-side recording.  I'll let you how I fare.