Ms-Stereo - Some help????

[Steve House]

If that is the case, you would have to use a small condenser, probably a small diaphragm condenser for both the the figure 8 and the cardioid. Is that correct?

One doesn't necessarily 'have' to use a small condensor - you could, for example, use a pair of AKG C414. With its switchable pattern you could set one to cardioid and the other to figure-8 for M/S or set both to figure-8 for Blumlein. But if I had a small diaphram cardioid and was looking for a figure-8 to use with it, I'd look first for a small diaphram. The point is to shoot for a match in timbre, sensitivity, etc, for the same reason you would try to use a matched pair of mics for X/Y micing. Using a small diaphram mid with a large diaphram side could sound strange.

 

[Steve House]

So...If i record by this way, directly for the recorder, you are saying that in post-production, i could use the "ms-decoder", to do this? to get the result as well as i could get by doing what i said before?

and, if i do by the way you said, i would record the "side" mic as a mono and the middle as mono too, as well...???

Your idea of using a reverse wired cable to flip the side signal and trying to mix the two versions of the side with the mid channel in a mixing desk just seems a pretty wonky kludge to me, going to be hard to adjust levels and balance as the pan and fader contrls no longer do what they normally do to the signal. There's nothing wrong with the theory, just I think it'll be hard to pull it off in practice and have it come out right. There are hardware M/S matrixers that take the mid and side mic inputs and matrix them into a L & R stereo pair and what you're describing is exactly what they do, albeit they do it electronically - my SD442 has an MS Link switch that sets it up right inside the mixer, disabling and reassigning the mixer's input one and two pan, gain, and fader controls so they can be more readily used to control the process. Recording the mid and side mics "raw" as two mono channels and doing the matrixing to stereo in post using a plugin for your audio workstation software is the best way to do it if your mixer doesn't include a hardware matrixing circuit and has strong merits as a workflow even IF your mixer supports matrixing as you shoot. Second best is to duplicate the side track, inverting one, and manually mix the side copies with the mid in your workstation.

It's unfortunate that the terminology of recording is sometimes confusing. A recorder or camera is casually said to be recording a "stereo" track because it's recording mics going into two channels labeled left and right. But each channel taken by itself is actually a mono channel - they're not mixed together in any way. Also, recording two mics do not make it stereo. It's only "stereo" if the mic feeding each channel is arranged so that the two mono signals being recorded have specific time, level, and phase relationships to each other so the original acoustic space can be recreated on playback. If they don't have that relationship, that "stereo" track is more appropriately called "dual-mono" where the two mono signals being recorded have no particular relationship with each other. For instance, putting a boom mic on the left channel and a lavalier on the right is a common practice - that results in a stereo track but it's by no stretch of the imagination a stereo recording. Multi-track audio software makes a distinction between stereo tracks and mono tracks because when you do multi-track recording you send each mic to its own separate mono channel and mix them to output stereo in the software. So in a multitrack workstation you'll find you can have projects containing both stereo tracks with two channels and mono tracks with only one channel. When you capture the video from a camera and send it to your workstation, its two audio channels usually are imported as a single stereo track but it doesn't have to stay that way.

Let's say you want to record M/S in-camera (assume you have two XLR inputs, marked left and right on the camera). You just plug the mid mic in where the left channel mic normally goes and the side mic where the right channel normally goes. The result is one "stereo" track that really consists of two mono channels. When you capture that in your audio workstation back at the barn, you have a "stereo" track in that it has two channels but not a stereo recording because the channels aren't yet in a true stereo relationship to each other. Sending that track through the M/S matrixing plugin results in a true stereo signal being output. Or if you want to manually matrix them, most better audio software allows you to split out the two channels of the "stereo" track to make them into two separate mono tracks. Splitting them, then copying the resulting side track to a third mono track and inverting its phase, results in three mono tracks, mid, side +, and side -, which you can then mix in the software to produce your left (mid plus side +) and right (mid plus side -) stereo output. The only downside of doing it like this is that when you monitor the camera audio as you shoot you don't hear stereo in your phones, you hear the mid mic in your left ear and the side mic in the right. (Again, the better mixers like my 442 actually have a M/S matrixing circuit on the headphone monitor as well so I can record the original mid and side mic signals as is but monitor them matrixed to stereo.)

 

[Noiz2]

Sorry for that, but i want to experiment! The sound will be perfectly captured by my shotgun mic, and with this ms-technique, i just want to experiment! sorry if i cause you so much trouble... by the way, do you know Frank Capra?

Do you know that he started to make cinema without knowing anything? well, that's just an example, but by your opinion, if you were there at that time, you should advised him that he souldn't started to make cinema...

People should experiment, and all i asked was some help with this technique...if i'm bothering you, just don't reply, ok?

Really, was he just born? I rather think he knew a lot. He didn't start directing till the mid twenties but he had worked as an editor as early as 1915 and worked as a prop man, a writer, an assistant etc. You seem to think he was an "auteur" who just grabbed a camera and started making films. Quite the opposite he worked his way up in the early studio system. On to of that he started out as an engineer, so not quite the starry eyed kid. Most people in film started "not knowing anything", about film anyway. I do know a few of them but Capra died in 91 so I didn't know him, though I have worked with his son. James Cameron started out as a trucker. Maybe he's a better example? I do know him and if you "experimented" on his sound track he would ...&*&*... (OK he is a bit extreme, most would just fire you). I'm not opposed to experimentation, but to quote one of the inventors I used to work for, "only an idiot reinvents the wheel". M/S is not "experimental" it is a quite common technique. But of course you were NOT going to record M/S. You were going to record some semi stereo two track recording. If you do it wrong then the image will be all screwed up and you might well have phasing etc going on it the track that makes it useless. Your a student your supposed to be learning, crack a book do a little research it's not rocket science. Sorry if that seems rude but anyone who runs around comparing themselves to Frank Capra and claims they will record "perfectly" but is trying to do what they call M/S and has obviously not even taken the time to Google the term just makes me smile. As a rule I wouldn't care but since I work in post I'm the one that has to try to polish the turds that come from folks who call it experimenting to excuse a woeful lack of preparation.