Stereo for mono sound engineers

[Jonathan Morrow]

This may be a little too big a subject for you but here goes:

I got myself a figure eight mic and an Audio Developments AD261 so I can collect some stereo sound. I would like to use it, but ... I have been deaf in one ear since I was 3 years old - I have no idea how stereo sounds, or how to use it. I can see that a stereo image of a scene should match the visual image, and I suppose that my gear will collect that information, but what do you do with close ups, or changes of view point? Do you move with the camera? Or do you try and maintain an overall big stereo picture for everyone to hold onto so they don't get confused? Like I am ....

Good luck to us all on this one.

[Steve House]

Originally Posted by Jonathan Morrow

This may be a little too big a subject for you but here goes:

I got myself a figure eight mic and an Audio Developments AD261 so I can collect some stereo sound. I would like to use it, but ... I have been deaf in one ear since I was 3 years old - I have no idea how stereo sounds, or how to use it. I can see that a stereo image of a scene should match the visual image, and I suppose that my gear will collect that information, but what do you do with close ups, or changes of view point? Do you move with the camera? Or do you try and maintain an overall big stereo picture for everyone to hold onto so they don't get confused? Like I am ....

Good luck to us all on this one.

A figure-8 mic DOES NOT capture stereo. It produces a mono signal of sounds coming at it from the mic's front and the rear while rejecting sounds coming at it from the sides. You still have mono. You need to add a second mic to record stereo with it, most commonly a cardioid pattern mic. The cardioid is aimed at the centre of the group and captures the "mid" signal, the figure-8 is aimed sideways so its axis is at a 90 degree angle to the cardioid and captures the "side" signal. It's arranged so the "front" of the figure-8 pattern points left. To get stereo you have to do some matrix trickery. The mid mic is mixed with the side mic and the result becomes the left stereo channel. A copy of the side mic signal is inverted 180 degrees in phase and mixed with the mid signal to become the right stereo channel. Some mixers have the ability to do this in the mixer itself - some just for monitoring, others decoding before sending the resulting stereo signal out of its outputs, still others not touching it at all - read your manual for what yours offers. But not to worry ... if your mixer only offers monitor decoding, or none at all, you simply record the mid mic to one channel, the side mic to the other channel, and do the matrixing in your editing software in post. The main thing for you now is to get the mid mic you need for it all to work. It should be a close match sonically to the figure-8 so if you tell us what mic you have we might be able to offer suggestions for a good mate for it.

As for how to handle the stereo once you've got it, you pose a classic dillema that is typically answered by .... are you ready? .... you don't shoot dialog stereo! Stereo is normally reserved for music and ambience, both of which represent a stable soundstage that does not shift with camera angle or position. Dialog is normally shot in mono and mixed to the centre channel or equally between left and right so it appears to come from centre screen. Remember that a mono recording can be made to sound like it's anywhere from full left to full right by the use of the pan controls when the sound is finally mixed during post.

[Gary Nattrass]

As Steve says keep all location dialogue in mono and then post produce it into stereo by adding buzz tracks and music if required. You will be able to control the stereo image better and you can then use M/S phase meters to get a visual indication of the stereo imaging.
This is what I have done as a pro dubbing mixer for 28 years and is industry standard so it is tried and tested.

[Jonathan Morrow]

Originally Posted by Steve House

A figure-8 mic DOES NOT capture stereo. It produces a mono signal of sounds coming at it from the mic's front and the rear while rejecting sounds coming at it from the sides. You still have mono. You need to add a second mic to record stereo with it, most commonly a cardioid pattern mic. The cardioid is aimed at the centre of the group and captures the "mid" signal, the figure-8 is aimed sideways so its axis is at a 90 degree angle to the cardioid and captures the "side" signal. It's arranged so the "front" of the figure-8 pattern points left. To get stereo you have to do some matrix trickery. The mid mic is mixed with the side mic and the result becomes the left stereo channel. A copy of the side mic signal is inverted 180 degrees in phase and mixed with the mid signal to become the right stereo channel. Some mixers have the ability to do this in the mixer itself - some just for monitoring, others decoding before sending the resulting stereo signal out of its outputs, still others not touching it at all - read your manual for what yours offers. But not to worry ... if your mixer only offers monitor decoding, or none at all, you simply record the mid mic to one channel, the side mic to the other channel, and do the matrixing in your editing software in post. The main thing for you now is to get the mid mic you need for it all to work. It should be a close match sonically to the figure-8 so if you tell us what mic you have we might be able to offer suggestions for a good mate for it.

As for how to handle the stereo once you've got it, you pose a classic dillema that is typically answered by .... are you ready? .... you don't shoot dialog stereo! Stereo is normally reserved for music and ambience, both of which represent a stable soundstage that does not shift with camera angle or position. Dialog is normally shot in mono and mixed to the centre channel or equally between left and right so it appears to come from centre screen. Remember that a mono recording can be made to sound like it's anywhere from full left to full right by the use of the pan controls when the sound is finally mixed during post.

Originally Posted by Gary Nattrass

As Steve says keep all location dialogue in mono and then post produce it into stereo by adding buzz tracks and music if required. You will be able to control the stereo image better and you can then use M/S phase meters to get a visual indication of the stereo imaging.
This is what I have done as a pro dubbing mixer for 28 years and is industry standard so it is tried and tested.

Hi Guys

Thanks for the replies. I have the AKG blueline series of mics, I got the figure 8 CK94 along with a hypercardiod and cardiod CK91 and CK93 (I think, they are in with the sleeping baby at the moment so I don't have access). I also managed to get a MKH416T on eBay for £175 so I hope I have enough gear for the time being.

As for mono dialogue I see what you are both saying, when there is only one person in shot anyway. Do you try and create some stereo from the panned mono when you have 2 people (or more) in shot?

Also what about this stereo background, is it totally fabricated? Do you try and avoid any of the dialogue being in it? i.e. would you capture it at a different time to the action you are filming? I have 4 inputs on my mixer, I assume I would have an M-S pair on say 1 and 2 and then another mic or two on the remaining inputs. But, since I only have 2 outputs, it needs to be in the replace stereophonically before it is recorded surely?

M/S phase meter? Where do I get one of those?

Cheers, Jon

[Gary Nattrass]

Panning dialogue should only be done if the line is off camera and needs to be placed for effect, you will find if you mess around with the stereo dialogue placement that it becomes distracting as you are looking straight ahead at a single screen.
Most of the stereo backgrounds I use have been sourced from libraries or recorded by myself, it also helps in pro dubbing when producing Music and Effects only dubs for international sales.

An M/S meter is available as a plug in for my pro tools system its called phase scope:http://akmedia.digidesign.com/produc..._1234_8561.pdf

You can see an example of an M/S phase scope here:http://www.soundtechnology.com/simage.html

You can get stand alone hardware versions too but they arent cheap.

[Nick Flowers]

If given the chance a recordist will record an atmos track at least in mono or, if the production wants it, in stereo. If the chance ISN'T given the recordist will moan and sulk and say: "You'll be sorry." The sooner it is grabbed after the synch stuff has been shot, the better, as it will better match what was in the background then. Clients new to the game sometimes wonder why we are all keeping quiet for a minute (how long an atmos track do you prefer, Gary? I find it hard to keep the crew quiet for longer than a minute!) while I mouth the numbers up to 60 with the mic roughly in the same position as where it was on the take. Room atmos is just as important as exterior fx so that dubbing mixers can fill in gaps and smooth over joins.

Nick F.

[Gary Nattrass]

I min is usually fine as we can loop it in dubbing, room atmos is also important in mono as it can cover difficult edits although using my main disk editor an AudioFile small overlaps can be done to dialogue on the same track.

Of course other stereo tracks can be added for effect and in the case of The Bill we would lay up to 20 tracks of stereo fx so that we could change the feel during the dub, for eg the hospital or office scenes would have all sorts of things going on that were then blended for the final stereo sound stage.

Take a listen to this clip it is totally produced in post prod by yours truly, the only sync sound is the clips of mono dialogue:http://www.youtube.com/watch?v=2PmQfg2rx14

[Nick Flowers]

Impressive, Gary!

I'm amazed that you can achieve all that within the schedule that The Bill has. Much respect.

Nick F.

[Steve House]

The Waves S1 plugin has a number of good controls for working with MS signals as well as stereo signals.

[Gary Nattrass]

Originally Posted by Nick Flowers

Impressive, Gary!

I'm amazed that you can achieve all that within the schedule that The Bill has. Much respect.

Nick F.

Thanks Nick I stopped doing the show three years ago as the stress was just too much, you have four days but one of those is taken with viewing with the director and loading the omf's. That leaves three but they then throw re-edits and all sorts of dialogue replacement sessions into the pot. Its a bit better now as they have a dedicated suite for re-edits but I dont miss it one bit. Heartbeat was a lot more civilised, five days to track-lay and two to mix but I suspect that has all changed too.
Sorry for slight hijack of post, using M/S meters can be a good indication of stereo image and you get used to the correct patterns in time to get a good wide image.

The scene is completed here:http://www.youtube.com/watch?v=RB47_wUY_uA&NR=1
Quite proud of that ep as it was all done in post as I said and there were no re-edit notes from the prod's.

[Jonathan Morrow]

Well, I thought I would get a response from some technologically informed amateurs, so I am thrilled by the replies. I need some time to study the you tube clips, but I would like to know: are they in stereo on you tube? I can't tell myself...

I am very excited by the knowledge that I am able to connect with on this website (I read much more than I post). Let me get on with some recording and I shall let you know how it goes.

PS my speciality is atheist propaganda, and I have been trying to revive the fortunes of Cains brewery tonight, might be a bit too late though.

[Gary Nattrass]

Glad to help and yes the your tube clips are in stereo although at a fairly compressed bit rate like all internet clips but it gives you an idea of pro dubbing of mono dialogue only and adding all effects in stereo. I just wish I had the same clip with no effects added so you can see the difference.

Sad to hear cains brewery going under but from what I have heard tonight from a customer of mine who is an ex whitbread quality control guy who advised them before the last takeover the beer was shite anyway!