Topic: figure 8 mic for M/S stereo setup

[ingsy]

I have used a 41 in an acoustic recording session of harp and bagpipe and it came out incredible (anyone want to hear it?). 

yes please 

[saneproductions]

I would love it!

[midside]

Ask and you shall receive:

http://www.yourfilehost.com/media.php?cat=audio&file=harpandbagpipe.mp3

Here's a picture of the harp (sorry no rig in this pic):

[ingsy]

that recording sounds great!  nice job.

[BayTaynt3d]

Number one, why are people saying right off that a Schoeps supercardioid isn't the optimal "M" microphone for an M/S pair? The "M" microphone can be any type that would give you a good mono recording by itself; there is no pre-ordained ideal type or pattern for "M". I've seen a few on-line descriptions of M/S that specify cardioid as if it was the Only Officially Correct "M" pattern, but they are simply mistaken both historically and technically.

Well, couple of things this thread made me think of.

For starters, sure you could use a card, hyper, or even an omni for mid, but don't think for a minute it's not going to make a HUGE difference in the recording you make cause it will. The reason hypers probably aren't ideal is because they're real narrow in their patterns, meaning they are going to be pretty focused straight ahead. This results in several things. One is, you're probably going to need more side than you would with a card or omni. The other is that hyper is going to be attenuating the more wide sounds. Both of those things combine into much more OFF-AXIS sound being used by both mics. Simply put, off-axis sound doesn't sound as good as on-axis sound, so you better have some damn good mics or everything's going to be colored by that fact alone. Also, depending on the hyper's narrowness and the fig 8's pattern, you may actually end up with some blind spots in the resulting combined pattern, which goes back to my point about needing more side that you would have needed with a card or omni. That would be ESPECIALLY true if you used a shotgun. Remember too about the "proximity effects" of directional mics. The more directional, the more proximity effect.

The main point of M/S, when Lauridsen introduced it in the 1950s, was its guaranteed compatibility between mono and stereo. The mono version of the recording came directly from the "M" microphone; you were supposed to use whatever microphone for "M" you would use for an optimal mono recording. Back then, good engineers all still knew how to make good-sounding mono recordings, and cardioid microphones certainly weren't their only choice for doing so!

I don't think that bolded part is true at all. All coincident stereo techniques are mono-compatible (MS, XY, Bluemlin, etc.) because the sound arrives at both capsules simultaneously and doesn't suffer from phase or timing differences. When they collapse these stereo pairs down to mono, they STILL USE BOTH MICS' signals. They don't throw away the side at all, they just downmix the stereo signal to mono and everythings fine. In fact, in most cases today, the downmix to mono doesn't even happen on the recordist's side, it happens on the end-users' side. Think about it this way, you record a concert and broadcast it over cable TV along with the video and the audio is in stereo. As long as they use a mono-friendly stereo signal, for the folks who watch the program on crappy small or old TVs that only have one speaker, it'll still sound OK because the L and R won't be phase-cancelling each other. Also, here's another example, say you're recording a huge symphony from the sweet spot above the conductor's head with a single stereo MS pair. If the mono signal you created was simply only from the one cardiod facing forward, it's sound like ass cause you wouldn't hear much of the symphony from the left or right sides. What they WOULD do is simply mix the MS to stereo, then downmix that to mono where BOTH mics would still be used. Think about it this way, what about XY and Bluemlin? Which mic would you pick for a mono recording in that case? You'd pick BOTH and downmix to mono. Take Bluemlin for example, in a classical or chamber music environment, that setup brings in a lot of the ambience of the hall plus the direct sound of the musiciancs, in your mono downmix, you'd still want all of that in there.

I have used an MK41 for the mid cap in many MS recordings and they come out great.
It's all about what you want.
For the record, the 41 is the cap of choice for many camera operators (news and motion pictures) as it helps narrow the field.
I have used a 41 in an acoustic recording session of harp and bagpipe and it came out incredible (anyone want to hear it?).

Yeah, but that said recording would probably have sounded way, WAY better using split omnis or a card pair. Remember, this forum is all about recording music, so don't take this the wrong way, but you'd pretty much never see someone record an acoustic harp and bagpipe in a studio with a shotgun, and there's a really good reason for that. So, shotguns and hypers all have there place, especially for ENG and video work, and even at times for music, but it'll be a rare, rare day that they'll be able to compete with a good card or omni under the right conditions. The difference would be night and day in all likelihood.

Anyway, just some observations from my end...

[musicsherlock]

Some great observations there...

I've actually been re-thinking this whole M/S thing...what is the end result of a good M/S mix?

Matched Hypers...



I think investing in a great pair of Hypers and using the appropriate set-up would minimize alot of post production time...

[Brian Skalinder]

I think investing in a great pair of Hypers and using the appropriate set-up would minimize alot of post production time...

You'd lose the flexibility of defining the stereo image width in post, though.

[BayTaynt3d]

I think investing in a great pair of Hypers and using the appropriate set-up would minimize alot of post production time...

You'd lose the flexibility of defining the stereo image width in post, though.

Which is one of the best reasons to use MS in the first place.   

[BayTaynt3d]

Some great observations there...

I've actually been re-thinking this whole M/S thing...what is the end result of a good M/S mix?

Matched Hypers...



I think investing in a great pair of Hypers and using the appropriate set-up would minimize alot of post production time...

Actually, it's more than just having the flexibility of post-imaging. For example, one of the reasons I'd love to do some MS is b/c of the music I tend to record, and how I record it: acoustic jazz in small venues. Being able to slap a MS on-stage would be fantastic. Think about a scenario I just had the other day: tenor on the left, clarinet in front, and trumpet to the right. Due to circumstances, my stand had to be right in their face, specifically right in the clarinetist's face, he was super-close to the mics, with the trumpet and tenor farther off to the sides. Man, MS would have killed in that situation b/c I would have been able to crank the S and lower the M and just flat-out nail the balance with mostly on-axis sound for everyone. What would you have done their with a pair of hypers? You'd have been screwed with either focusing on the center clarinet and not getting much of the tenor or trumpet, or you'd have angled them out and picked them up great but completely attenuated and colored the clarinetist straight ahead. So, I don't think a pair of hypers would ever come close to the flexibility you could get with MS, especially when you start bringing a hyper, card, sub-card, or omni into the M channel -- you can create all sorts of different patterns with those combos, when with hypers, you're patterns are extremely limited IMHO. And FWIW, I ended up using 18" split 482 omnis in that situation which ended up sounding pretty damn good, heh. Samples are in the first post on my website right now (note: it was split 482s + DI off the bass > R4, and I so wished I had time to set one overhead on the drumkit, but oh well...).

[DSatz]

Hello, BayTaynt3d. Of course it matters what kind of microphone you use for "M"--I was only saying that M/S isn't a technique with a fixed "recipe" in that respect; the "S" microphone must of course be a figure-8, but as I said, any appropriate type of "M" microphone can be used. The original poster makes mono recordings often, and this technique should be a natural extension of that. I'm eager to hear how this will go for him.

Second, you're completely right that off-axis sound is very important; in fact I would say it is far more important than most people realize, until they leave the studio (or the basement apartment) and start to make two-microphone stereo recordings in concert halls, churches, etc. But you seem to assume that all microphones have equally poor off-axis sound quality, and that is decidedly not the case.

This is a little hard to say in one sentence, but: Microphones whose response is primarily based on the pressure gradient (i.e. microphones tending toward a figure-8 pattern) tend to have off-axis response that more closely matches their on-axis response than microphones whose response is primarily based on sound pressure alone (i.e. microphones tending toward omnidirectional). The upshot is that a good supercardioid such as the Schoeps, which has very flat on-axis response and a very "clean" polar pattern (i.e. it is a supercardioid throughout almost its entire frequency range) will have audibly smoother, flatter off-axis response than any cardioid microphone of normal size. That's why it is one of the preferred microphone types in film and video sound. It's not only because it suppresses off-axis sound efficiently--more often than not, people have an exaggerated notion of how narrow a supercardioid directional pattern really is. But mainly, the reason such microphones are used so much is because the sound which is, inevitably, picked up from off-axis still has a very listenable quality to it.

Just so you know, I've made perhaps 2,000 live stereo recordings of classical music concerts and recitals using coincident or near-coincident pairs of Schoeps supercardioids; they've been my "go to" microphones for about 25 years now. In that application the off-axis response is absolutely crucial to the result--the center of the sound source is generally hitting the microphones at a 45-degree angle or a little greater. So any harmful coloration would be immediately evident, if it was really a defect of those microphones as you seem to assume.

When you talk about possible "blind spots in the resulting combined pattern," I can only think that you have a somewhat confused mental picture of how M/S recording works; "blind spots" aren't a problem at all, either in theory or in practice. Similarly, what you said about the mono compatibility of X/Y stereo recording is perfectly true--but please note that when you sum L + R from an X/Y (coincident) microphone pair as you discussed, you get the precise equivalent of M in an M/S pair. Or to put it the other way around: L and R are obtained from an M/S pair respectively by adding (L = M + S) and subtracting (R = M - S) the microphone signals. M is the mono sum to begin with, and S is the difference between the L and R stereo channels. It's exactly parallel to the way FM stereo is broadcast. A mono FM receiver gets only M (= L + R), while a stereo receiver gets M but can also detect a subcarrier which is modulated at the transmitter by the L - R signal (= S). In stereo mode, this S signal is matrixed with M to get L and R.

So the S signal in an M/S recording is simply ignored if you want the compatible mono version of the recording. When you think about it, you'll realize that it must be so. The two lobes of a figure-8 microphone are in opposite polarity, so you can never mix any amount of the S signal into M without causing the result to favor either the left or the right of the original sound picture. Most people who make this mistake have not fully realized the part about the two lobes of the figure-8 having opposite "sign." A figure-8 has a cosine pattern, and the cosine of any angle between 90 and 270 degrees is negative. This isn't obvious from a normal polar diagram but it is an essential fact of any bidirectional microphone (including the supercardioid, by the way--its rear lobe has inverse polarity, too).

--best regards

[sygdwm]

i wish i could comprehend all of that.

[saneproductions]

I really appreciate all of the running commentary on this topic. I certainly didn't expect this amount of response or the richness of detail offered. I can't think of any place in the world I could get this advice. I feel like I should start writing checks!

I am excited to try a M/S recording and I will report back after I do. The concert is on the 18th of this month and I plan to go to a rehearsal the day before and do some tests.

Thanks again!

[midside]

Yeah, but that said recording would probably have sounded way, WAY better using split omnis or a card pair. Remember, this forum is all about recording music, so don't take this the wrong way, but you'd pretty much never see someone record an acoustic harp and bagpipe in a studio with a shotgun, and there's a really good reason for that. So, shotguns and hypers all have there place, especially for ENG and video work, and even at times for music, but it'll be a rare, rare day that they'll be able to compete with a good card or omni under the right conditions. The difference would be night and day in all likelihood.

Anyway, just some observations from my end...

This is turning into an interesting thread, but I must comment on some of these points:
First - You should use caution with the word 'better'.  Better can mean different things to different people.
Second - I would hardly compare an MK41 to a shotgun microphone.
Third - I also wouldn't compare a live location recording to what would be done in a studio.

With all this in mind, if I was to record this again, perhaps I would do something slightly different but I wouldn't go with split omnis.  The room was just too open for this type of recording.  I picked MS with a 41 for a few reasons, two being of high importance:
1. I wanted a very tight, directional upfront sound.
2. I had to nail it that day....

If I was to do it again, perhaps I would try out an MK4 and arrange the performers a little differently...or, just mic each instrument separately and pan a pseudo stereo image in post.

Now, some people do not fully understand MS recording and think that adjusting the mid to side ratio is:
1. more side = wider
2. more mid - narrower
THIS IS NOT THE CASE!
First off, let's assume for explanation purposes that the mid and side recording levels are approximately the same.
You have the widest stereo image possible when the mid to side ratio is 1:1
When you adjust to all M, you have a mono recording of the M cap only.
When you adjust to all S, you have a mono recording of the S cap only.
Everything else is somewhere inbetween.
It obviously sounds more narrow when you adjust heavier on the M cap in post and it is.  But, the thing most people don't understand is that when you adjust heavier on the S cap (past 1:1) that the image is not getting wider, it is actually getting narrower but with more information from the sides.  It might sound wider, but that is just because of the extra room ambiance.
For instance, if you have one musician on the left and one on the right, and you want to hear them in the proper place, then a close to 1:1 will be the most accurate (depending on the caps used).  If you adjust to the S cap only, then both musicians will be placed equally on the left and right (mono from the side cap).

So, if you really want to make it sound wider than it is (in post), then the best thing to do is lower the gain of the mid (in your audio editor), or raise the gain of the side.  Then, matrix 1:1.  That will give you the truest wider stereo image.

MY MAIN REASONS FOR USING M/S:
I must admit, that while I love the sound of MS, it is (of course) not always the best method to use.
As we all know, different recording situations call for different techniques.
I use M/S a lot because I record mainly in the field and usually do not have a second chance....it's quite easy to get quality material, then 'fix it up' in post.  Just pick your M cap, get in a good location or arrange performers (if you can), get good levels and record.
Later on, if I think the room is too boomy or hollow, etc., I go with more mid.
The waves S1 shuffler is a great tool (works with LR recording too).  (If you use MS techniques and you don't know what shuffing is...then NOW is the time to learn!)
You can also isolate mastering effects (EQ, de-hisser, multiband dynamics, etc.) on the mid or side channel before you matrix it.....
M/S really gives you many great post benefits.  Plus, I can fit two caps in a tiny little rycote for outdoor work.  Great set-up for 'run and gun' or 'no take 2' situations.

Remember, recording techniques/equipment are just tools and there is no replacement for knowing how to use your tool.

With all that said, if I was going to record a symphony in a good sounding room, M/S would NOT be my first choice....I would probably run split omnis from overhead

[midside]

p.s. don't forget to look here:

http://groups.google.com/group/rec.audio.pro/search?hl=en&group=rec.audio.pro&q=ms&qt_g=Search+this+group

[DSatz]

midside (gee, with a name like that, it's no surprise to see you in this discussion)--when BeyTaynt3d says that an omni or cardioid would have sounded "better" than a supercardioid, he's being opinionated, of course.

But I think there's a very real basis for his opinion. There is something hugely desirable about the sound and feel of a well-made recording when omnidirectional (i.e. pressure) microphones are used. The stereo image may be only a vague, wandering mist, but if you change to a "right-brained" listening mode in which you are receptive mainly to tone color, there can be sensual goodies galore. For many musicians, that is the only mode in which they ever listen or even consider listening. For them, localization is but a parlor trick; who cares where everybody was exactly on the stage? They like the fact that real space is being bypassed or abolished.

I can see their point very well, but I hear both ways at the same time, and I don't want to abandon all spatial perspective completely. To discuss this would carry us even farther away from M/S, so let me just say that lately I've become keen on using wide cardioids for stereo recordings when room acoustics allow. You can get about 75% of those sensual pressure-transducer "goodies," while with proper setup you can also have a clear, stable stereo image. (A sphere stereo microphone can also give you "the best of both worlds" in this way--that's a fascinating way of recording.)

Interestingly, it appears that European engineers use omnidirectional microphones for studio recording more often than American studio engineers do. (I mean pressure transducers--not the "omni" setting of a multi-pattern microphone such as a U 87, which synthesizes its "omni" pattern by summing the signals from two back-to-back cardioids.) Typical American studio engineers never look at any pattern other than cardioid; their fidelity to the cardioid pattern is often greater than their fidelity to their wives.

--dre, can I encourage you to ask whatever questions are on your mind about this stuff? When you're really interested in something is always the best time to learn. If need be, we can start another thread to avoid hijacking this one, or we can latch on to an existing thread if you know of one that's more similar to what you want to talk about. (My guess is, it has to do with directional patterns and maybe polar diagrams.)

--best regards