Author Topic: M-S setup question (Read 10396 times)

china_rider · « **on:** October 16, 2007, 11:24:28 PM »

Hey all... I've not had much success in my Mid Side recordings yet and just wanted to verify I've been setting up correctly. So I've been putting the mid card in the right channel with the figure 8 in the left with the front of the figure 8 pattern facing left. Is this what decoders in post are expecting?

KLowe · « **Reply #1 on:** October 17, 2007, 12:21:22 AM »

Side goes into the right channel with the positive lobe facing left.

I remember "Side" kindof rhymes with "right"

John Willett · « **Reply #2 on:** October 17, 2007, 10:05:11 AM »

Quote from: china_rider on October 16, 2007, 11:24:28 PM

Hey all... I've not had much success in my Mid Side recordings yet and just wanted to verify I've been setting up correctly. So I've been putting the mid card in the right channel with the figure 8 in the left with the front of the figure 8 pattern facing left. Is this what decoders in post are expecting?

Wrong channels - Mid is always left as this corresponds to a mono signal on an old half-track tape.

Side goes in the right - but you are correct in saying that the +ve lobe faces left.

china_rider · « **Reply #3 on:** October 17, 2007, 11:58:26 AM »

+T to all. That explains the problem. Glad I asked after only trying 2 shows... Also glad I was running my AKGs on the other 2 channels to save the show.

anhisr · « **Reply #4 on:** October 17, 2007, 12:22:04 PM »

Are you mixing on the fly or in post?

china_rider · « **Reply #5 on:** October 17, 2007, 12:26:51 PM »

Quote from: anhisr on October 17, 2007, 12:22:04 PM

Are you mixing on the fly or in post?

In post and I have the raw files so I can just reverse the channels and try again once I get some time.

anhisr · « **Reply #6 on:** October 17, 2007, 01:15:50 PM »

correct. I have had to flip the channels when I first started doing M/S sometimes.

Frank in JC · « **Reply #7 on:** October 17, 2007, 05:30:14 PM »

I know you've fixed the problem already, but...

Depending on the software you're using to mix, it may not matter which mic is which channel so long as you perform the the correct summing. This assumes the positive lobe of the figure 8 is pointing left:

LEFT CHANNEL: cardioid signal + figure 8 signal
RIGHT CHANNEL: cardioid signal - figure 8 signal (which is same as, cardioid + out-of-phase figure 8 signal)

ghellquist · « **Reply #8 on:** October 17, 2007, 06:13:26 PM »

A quick fix may be to simply invert one of the channels (no need to redo the mix then). The main result of putting the M mic in the Righthand channel instead of left is that the channels get different phase getting a quite fuzzy stereo image. A simple invert of one of them will correct that part, putting the stereo back in the middle. You may try to listen for which one to invert -- some people can hear absolute phase but most cannot as far as I have tested.

Gunnar

china_rider · « **Reply #9 on:** October 18, 2007, 03:17:43 AM »

I went ahead and tried the chan swap for a show tonight. It only took a few min to remix in wavelab. It's better than the first mix... However, I'm still not happy with the results. I think I was not running M-S in the right situations but was just playing around since I had 4 chan so I knew that I would have my AKGs as a backup. Overall the mix lacks alot of bass and sounds bright enough that it comes close to giving me a headache after a few min. There is good stereo separation though.

Now that I got the modded TLs back I think I'm going to try M-S on stage at On the One on Tuesday. That should be a good test.

Thanks for all the help,
Dana

Frank in JC · « **Reply #10 on:** October 18, 2007, 08:03:17 AM »

Quote from: china_rider on October 18, 2007, 03:17:43 AM

I went ahead and tried the chan swap for a show tonight. It only took a few min to remix in wavelab. It's better than the first mix... However, I'm still not happy with the results. I think I was not running M-S in the right situations but was just playing around since I had 4 chan so I knew that I would have my AKGs as a backup. Overall the mix lacks alot of bass and sounds bright enough that it comes close to giving me a headache after a few min. There is good stereo separation though.

Now that I got the modded TLs back I think I'm going to try M-S on stage at On the One on Tuesday. That should be a good test.

Thanks for all the help,
Dana

If you're not hearing any bass, maybe somehow you're only getting the figure-8 mic, or it's too "heavy" in the mix? (Figure 8s being light in the bass by virtue of their design.)

I've used the TL's mid-side several times in small venues and always liked the results. I'll finally be putting them back to work soon and that's the pattern I'll probably stick with indoors. BTW, what's involved in the mod?

KLowe · « **Reply #11 on:** October 18, 2007, 09:02:05 AM »

I agree. Definately "tighten up" the m/s mix. Two much side gives no bass and a headache.

Soundforges M/S tool is very simple to use. Makes adjusting the width a breeze.

china_rider · « **Reply #12 on:** October 18, 2007, 12:46:14 PM »

Quote

BTW, what's involved in the mod?

It's a sort of unique one that Chris did by reqeust.... Put in some new caps and replaced alot of the electronics.

DeepCreatures · « **Reply #13 on:** October 19, 2007, 07:24:46 AM »

hope you don't mind me hopping on here china_rider...

the other day i finally gave the M-S a try. i use an LSD2 and put the bottom on card and left it pointed straight ahead. the top cap was put to figure-8 and rotated 90 degrees. i recorded just like that with really great results (i was quite surprised actually), although the right channel seems a bit heavy. the mix seems pretty solid, with good bass and all. anyway, i keep reading about needing to do post mixing for the best sound, but am quite lost on what needs to be done and what the results are. i currently use Cool Edit Pro. any help would be appreciated. thanks.

peace,
ts

Roving Sign · « **Reply #14 on:** October 19, 2007, 07:33:33 AM »

Quote from: DeepCreatures on October 19, 2007, 07:24:46 AM

hope you don't mind me hopping on here china_rider...

the other day i finally gave the M-S a try. i use an LSD2 and put the bottom on card and left it pointed straight ahead. the top cap was put to figure-8 and rotated 90 degrees. i recorded just like that with really great results (i was quite surprised actually), although the right channel seems a bit heavy. the mix seems pretty solid, with good bass and all. anyway, i keep reading about needing to do post mixing for the best sound, but am quite lost on what needs to be done and what the results are. i currently use Cool Edit Pro. any help would be appreciated. thanks.

peace,
ts

Unless the LSD2 has a built in MS matrix circuit - you abosolutely need post work.

http://www.dpamicrophones.com/page.php?PID=126

DeepCreatures · « **Reply #15 on:** October 19, 2007, 08:52:13 AM »

Quote from: Roving Sign on October 19, 2007, 07:33:33 AM

Unless the LSD2 has a built in MS matrix circuit - you abosolutely need post work.

http://www.dpamicrophones.com/page.php?PID=126

thanks for the link. so, if i am gathering this correctly, if the LSD2 has a built in MS matrix circuit then no worries. i am really not sure if it does or not - anyone know??? however, if it does not then i need to do the following in post:

Left channel=M + S
Right channel=M - S

so, basically do some channel manipulation with what i have. thanks!

peace,
ts

Shawn · « **Reply #16 on:** October 19, 2007, 08:57:15 AM »

the lsd2 doesn't have m-s decoding built in. you must do it with your pre-amp or with software.

DeepCreatures · « **Reply #17 on:** October 19, 2007, 09:18:05 AM »

with the pre-amp - interesting. is that possible to do with a UA-5 or am i stuck with post production? thanks again for the responses - +Ts

peace,
ts

Brian Skalinder · « **Reply #18 on:** October 19, 2007, 09:35:05 AM »

Quote from: DeepCreatures on October 19, 2007, 09:18:05 AM

with the pre-amp - interesting. is that possible to do with a UA-5 or am i stuck with post production?

You're "stuck" doing it in post-production. Which is better, really, as you have complete control over the mix in a clean, controlled environment.

In CEP/Audition: Effects | Amplitude | Channel Mixer | Mid-Side to L-R preset. Adjust the width by changing the relationship between the L and R values under New Left and New Right Channel. The greater the difference between the L and R values, the wider the stereo field. The smaller the difference between the L and R values, the narrower the stereo field.

Roving Sign · « **Reply #19 on:** October 19, 2007, 09:55:01 AM »

Quote from: DeepCreatures on October 19, 2007, 09:18:05 AM

with the pre-amp - interesting. is that possible to do with a UA-5 or am i stuck with post production?

Whats not being said is - some preamps (like the V3 I believe) have a built in MS matrix circuit...

DeepCreatures · « **Reply #20 on:** October 19, 2007, 10:02:03 AM »

thanks a ton guys! will play around with this tonight and see what comes of it.

peace,
ts

DeepCreatures · « **Reply #21 on:** October 19, 2007, 05:43:43 PM »

wow! that really opened up an already nice sounding recording. thanks a ton guys. will have to work with this recording method a bit more - i really like the results.

peace,
ts

DSatz · « **Reply #22 on:** October 20, 2007, 12:05:02 PM »

Permission to try opening some people's eyes here? If you record M and S signals directly, you're not stuck having to matrix the signals in post--you gain the ability to choose the matrixing parameters that sound best over loudspeakers.

For two-channel recording I use a Lunatec V3 with an M/S matrix built in, but I've never used that matrix and probably never will. For me the whole point of M/S recording is the ability to choose the matrix settings in the comfort of my living room, rather than having to guess at the settings while listening over headphones (and trying to keep people from knocking my mike stand over or stepping on my whatever).

You can do all sorts of useful things in post--you can EQ the low frequencies in the S channel before feeding the signals into the matrix, for example, which can vary the sense of spaciousness in a recording without altering its musical balance (much). But the main thing is, by controlling the gain of the S versus M signals going into the matrix, you can set the stereo width in relation to the degree of reverberant sound in the recording. There usually is one setting that feels the most "real" or "plausible," and in my experience it's almost never the setting that you would have gotten by accident.

(Increasing the amount of S relative to M increases the stereo basis width and adds more reverberant sound pickup; these two aspects of a stereo recording give an impression of the kind of space you were recording in, and some settings make far more sense to the listener than others. Unfortunately this is exactly the kind of thing that headphones tell you almost nothing about.)

I find it sad that some people apparently think M/S always means a cardioid facing forward, a figure-8 facing sideways, and accepting the given sensitivity and frequency response of these two microphones without question, as if God had handed those parameters down from Mt. Sinai. It's important to realize that the manufacturers of multi-pattern microphones have little or no control over the individual sensitivity and frequency response of one pattern versus another; the overall design is generally the best available compromise, but usually favoring the cardioid setting. It's certainly not optimized for any one technique such as M/S recording (at least not in the modern sense--though we could talk about this historically if anyone's interested).

The only things that aren't variable in M/S recording are the coincident placement, a figure-8 S microphone facing sideways, and the use of some kind of M+S/M-S matrix. The flexibility of M/S decoding is the greater part of its appeal as far as I'm concerned. Since every M/S arrangement is ultimately the equivalent of some theoretically possible X/Y setup, you might as well just use an X/Y setup if you're not going to optimize the matrixing parameters in post.

For that matter, since the S channel is generally several dB lower in level than the M channel, you can record both channels at full gain (whatever brings the maximum peaks up to -2 dBFS or whatever your chosen limit is) and in that way, gain a few extra dB of signal-to-noise in the eventual L/R stereo version of the recording.

--best regards

KLowe · « **Reply #23 on:** October 20, 2007, 12:11:13 PM »

DSatz. As always your posts are informative and helpful. Thank you.

Can you expand about what you do to the Side signal pre-matrix? I've always felt (that at least for PA taping)...that the side channel is the "necessary but weak link" in the M/S matrix. To me the Side sound is always "thin and distant".

Just curious. What do YOU do to EQ the side channel pre-matrix. Maybe I can learn a few tips.

Thanks.

Oh yeah... I agree wholeheartedly. M/S is great b/c YOU GET to alter the image in post. Not Stuck with it.

Kevin

DSatz · « **Reply #24 on:** October 20, 2007, 12:49:47 PM »

KLowe, thanks for the reply, and yes, listening to the "S" signal alone is instructive but not musically satisfying, and the general public shouldn't be exposed to it. It's kind of like, if you're a surgeon you can look at people and imagine in full color what their insides look like--but most other people don't like to hear chapter and verse about that, especially while eating.

I don't know whether people know how stereo FM broadcasting works, but it's just like M/S. The left and right channels are combined 1:1 and are broadcast as the main (or mono) signal. At the same time, the difference between left and right is derived by matrixing, and this "difference channel" (which corresponds exactly to the S channel of an M/S recording) modulates a 38 kHz subcarrier which is then demodulated in your FM receiver when it is in stereo mode--and the resulting signal pair is matrixed back into the original L and R signals. (Voila.) Mono FM tuners (which used to exist--my father had a nice McIntosh one in the mid-1950s) simply didn't have the subcarrier circuitry at all. For a while you could get add-on "stereo adapters" for mono FM tuners, but I digress.

In FM broadcasting the entire process has standardized gain settings, so there isn't generally any reason to adjust the matrixing parameters in your FM receiver. But as you know, sometimes stereo FM reception in fringe areas can be noisy, so some receivers have a "blend" control which reduces the difference channel and/or turns down the treble in the difference channel, thus preserving some L/R separation while reducing the apparent noise. That is analogous to processing the S channel separately before dematrixing.

With digital recording you can assume that the channels are quiet enough, so any adjustments you make will more likely be to improve imaging (increasing or decreasing spaciousness, as I mentioned, by playing with the S channel's low-frequency response) or tone color (reducing the sharpness of a peaky microphone for example, or making speech more intelligible, both of which can be done by equalizing M).

One important thing is, with a proper setup the S (or "difference") channel should never contain any direct sound that isn't being picked up in the M channel as well. If it does, then either you were miking too closely, or the pattern of your M microphone was too narrow for the stage width of whatever sound sources you were recording. It should always be possible to hear all the program material in the proper balance by listening to the M channel alone (in mono, of course).

M/S was introduced in the 1950s as a bridge between mono and stereo. The engineers who used it had all been picking up sound in mono for years, so they knew how to place a microphone for that purpose. The S microphone was then added on in the same location for compatible stereo recording/broadcasting. People who intend to record a lot in M/S, and who are sufficiently fanatical (in which case they are all immediately my friends), might want to practice making mono recordings that sound good, as a kind of preparatory exercise--it's extremely instructive, and a cool skill in its own right.

If you followed what I said about FM stereo--theoretically it would be possible to broadcast a live stereo pickup over FM by modulating the main carrier with the signal from the M microphone and the stereo subcarrier (the difference channel) with the signal from the S microphone.

Does that make sense?

--best regards

P.S.: I can't resist adding that in stereo LPs, horizontal groove modulation = M and vertical modulation = S; the 45/45 degree design of phono cartridges functions as the M+S/M-S matrix. Some moving coil cartridges exaggerate the M-S pickup, which gives more "air around the sound"--a characteristic that many audiophiles like. Carver used to sell a little processor called the "Digital Time Lens," built around an M/S matrix pair, that made digital recordings sound as if they were being played back through a cartridge like that.

Doc · « **Reply #25 on:** October 20, 2007, 05:00:15 PM »

I started using M-S with my TLs, love the sound and being able to play with the stereo spread in post; but, so far I have been able to set up on stage, and was wondering how far back from the stage can you still use M-S?

Tim · « **Reply #26 on:** October 20, 2007, 05:12:31 PM »

Quote from: Doc on October 20, 2007, 05:00:15 PM

I started using M-S with my TLs, love the sound and being able to play with the stereo spread in post; but, so far I have been able to set up on stage, and was wondering how far back from the stage can you still use M-S?

you can use it from anywhere in the room. the ability to dial in just the right amount of side can help you reduce the boominess of the room that you get running from a section.

Doc · « **Reply #27 on:** October 20, 2007, 08:18:19 PM »

Thanks Tim
I look forward to experimenting with M-S more

JiB97 · « **Reply #28 on:** October 20, 2007, 11:44:19 PM »

What do y'all think about using two different types of mics when running M/S. Say, you would use a ADK TL for the side channel and maybe a 480 w/ck61 for the mid channel? Would this sound too weird? Would the difference between a SD mic and an LD mic be too "strange" sounding.

Seems like it would be a lower profile setup than having (2) TLs being run vertically.

Has anyone on this board done this?

Thanks for the intelligent discussion regarding M/S. It is something I have not tried but would love to if I had a bi-directional microphone.

KLowe · « **Reply #29 on:** October 21, 2007, 11:19:13 AM »

I see no problem with running two different mics. The post matrix should blend them very well. There is an on-line tutorial ( Google Mid Side ) and you'll find that the sound engineer used two different mics. When my Schoeps MK4 gets back from Germany I can't wait to run the Schoes as the mid and the AK 20 on the side.

MS rules face for so many different reasons!

http://www.uaudio.com/webzine/2005/december/index4.html

DSatz · « **Reply #30 on:** October 21, 2007, 11:21:13 AM »

jbanyai, in principle there's nothing wrong with using two microphones of different brands or types--even a ribbon figure-8 for S and a condenser for M can work together well. But the stereo imaging can get weird if the two microphones have very different response characteristics especially in the midrange and upper midrange. It's not a great idea to pair a mellow S microphone with a brash M microphone, for example, because then the apparent position of any given sound source (instruments, for example) will vary at different frequencies; that can be a bit bizarre-sounding.

Interestingly (to a geek like me, anyway), this implies that sometimes a stereo microphone isn't the best answer, since most of them--the conventional dual-membrane kind with electrically switched directional patterns--change their high-frequency response when you change their directional pattern. (This is usually quite obvious in the spec-sheet curves, assuming that curves are given for each available pattern.) The best results might be when you choose two specific capsules whose frequency response matches well despite their having (most likely) different directional patterns.

As an example, the Beyer M 160 ribbon supercardioid is sometimes paired for M/S with the Beyer M 130 figure-8; both have very flat, smooth response and musically the combination works quite well (although their low sensitivity can cause problems). "Condenserwise" if you look at the response curves for Schoeps ("Colette" and CCM series), Neumann (KM 100 series) or Sennheiser (MKH series), nearly all the small-diaphragm capsules or microphones of each manufacturer have similar high-frequency response characteristics to the other capsules or microphones in the same series. All other things being equal, their similarity in frequency response is a good thing for M/S.

Large microphones, however, generally don't maintain their directional patterns very well at high frequencies. Ribbon microphones typically roll off at high frequencies anyway, thus dodging this problem to some extent--but large condenser microphones typically have narrower patterns above 6 - 8 kHz, and to my mind this makes them less suitabie for "S" microphones if you're trying for the best possible results. Neumann claims that their SM 2 was the first commercially available stereo microphone, for example, and that model used small-diaphragm capsules (the same ones as in the KM 56).

--best regards

Patrick · « **Reply #31 on:** October 21, 2007, 11:23:15 AM »

Quote from: jbanyai97 on October 20, 2007, 11:44:19 PM

What do y'all think about using two different types of mics when running M/S. Say, you would use a ADK TL for the side channel and maybe a 480 w/ck61 for the mid channel? Would this sound too weird? Would the difference between a SD mic and an LD mic be too "strange" sounding.

Absolutely nothing strange about it. In fact most M/s is done this way. Since not all small-diaphram microphones have fig-8 capsules (or any interchangeable capsules for that matter), it is not abnormal to mix and match different brands of mics.

JiB97 · « **Reply #32 on:** October 21, 2007, 04:22:05 PM »

Thanks for all the responses guys. +Ts all around.

uosdwis · « **Reply #33 on:** October 21, 2007, 05:56:13 PM »

DSatz, do you not even monitor the decoded signal when recording? I've been doing some fx recording in M/S without the ability to monitor properly, and even though I haven't really run into any problems I sometimes wonder if my recordings would improve if I could. One more nudge towards a 722, I guess. Any thoughts on this?

DSatz · « **Reply #34 on:** October 21, 2007, 08:55:58 PM »

uosdwis, I monitor M/S recordings via a very useful little battery-powered headphone amplifier and M/S decoder that AEA used to make (the "MS 38 Lite"), but I always record the M and S signals directly. So what I'm hearing over headphones is always just one of many possible eventual decodings of the recording.

The M-to-S gain ratio that sounds best over headphones isn't usually the same as what sounds best over loudspeakers--but that's OK, since I'll have the full range of options in post. If it sounds good over headphones, that tells me that the information is also there to make it sound good over loudspeakers later on.

--best regards

P.S.: When recording the M and S signals directly, if your two microphones have the same sensitivity, the S signal may well be 5 or 6 dB lower in level than M. If you raise the S channel's record gain so that both channels peak at approximately the same levels (-2 or whatever), you'll increase the signal-to-noise ratio of your ultimate L/R stereo version by a few dB.

This probably wouldn't matter with 24-bit converters, but when I record M/S on a portable DAT recorder it's what I always do; in classical concerts the audiences are occasionally quiet, so the difference may matter.

uosdwis · « **Reply #35 on:** October 22, 2007, 05:29:29 AM »

That's a nifty device. If I find one, I'll pick it up. What I end up doing is monitoring the mid signal and occasionally checking in on the side mic (when switching setups for instance). Beyond that I use my ears to find a good spot and I have yet to be unpleasantly surprised by what I get when decoding in post. But, it's not perfect.

china_rider · « **Reply #36 on:** October 25, 2007, 05:27:44 AM »

Hey now... Just wanted to give all a big thanks! Got my mod TLs back and ran M-S stage lip at on the one tonight. Had to take a quick listen before bed now that I know I am setting things up correctly. Still need to do the final mix and am just doing the preview now but wow this M-S sounds good with just the default audition settings. So again thanks for all the great advice in this thread. T+

china_rider · « **Reply #37 on:** October 25, 2007, 05:54:38 AM »

Quote

In CEP/Audition: Effects | Amplitude | Channel Mixer | Mid-Side to L-R preset. Adjust the width by changing the relationship between the L and R values under New Left and New Right Channel. The greater the difference between the L and R values, the wider the stereo field. The smaller the difference between the L and R values, the narrower the stereo field.

Ok... back to my stupidity about this other than default cable hook ups.

Defaults are:
New Left channel has L/R at 100 invert not checked.
New Right channel has L at 100 and right at -100 with invert checked.

Whats the proper way to play with the mix here? I assume the right chan should always be inverted and the left not (unless I mess up in setting up the mics.)

Should you adjust new left channel L/R evenly and not invert.

So about new right? Find some happy value for L/R between -100 and 100 and keep it inverted?

Does anyone have a way they go about this to get the best mix? Right now I'm just sort of randomly changing numbers in preview mode and not saving things.

Sorry for the 3am rambling but I'm so excited about the mix I can't go to bed until I play with it.

Stay Kind,
Dana

DSatz · « **Reply #38 on:** October 25, 2007, 11:06:53 AM »

china_rider, sorry I wasn't on the board at 3 a.m. your time, but as I recall in CEP/Audition there is a percentage value which you choose, and it determines the amount of S that goes into the (software) matrix.

The thing is, the optimal value depends heavily on the geometry of your listening setup among other things. If you have your computer connected to your main playback system, you can try a few different percentage settings and converge on a result that seems right. Otherwise you have to try a few plausible settings, write down which one is which, burn a CD from them, and run to your main system to try them out and choose. This can eventually wear tracks in the carpet between your computer and your stereo system. I sometimes prefer one setting on one day and a different setting on another day, but I'm an old '60s person and I find freedom intoxicating. If it were up to me, most musical recording projects would never get finished.

What you're listening for is the best match of stereo width and room reverberation; adding more S increases them both. With 0% S you have pure mono audio and the driest possible mix; with 100% S you have something that's very odd and "phasey" sounding, since it contains only incidental amounts of direct sound, plus you're hearing the same signal in both loudspeakers, but with the two speakers driven in opposite polarity from each other. Somewhere in between is nirvana (if not Nirvana any more).

The true nature of nirvana is that the spatial arrangement is plausible and the music has the mix of clarity plus room sound, all of which gives you the most convincing and pleasant possible feeling, somewhere on the spectrum between "this could really have happened like that" and "I wish this could really have happened like that."

Brian Skalinder · « **Reply #39 on:** October 25, 2007, 11:21:29 AM »

Alright, DSatz summed it up far more clearly and eloquently than I ever could have, but I'm going to post, anyway, since I spent the time typing it all up. If it just confuses things more, I'll probably delete it, but hopefully it will help a bit.

No stupidity here at all, Dana...we all have aspects of this hobby about which we're not fully knowledgeable, and for me, anyway, part of the fun is learning new things. I learned about Mid-Side a while ago when I had my 414s, others learned about it long long ago, and you're just learning about it now. Nothing stupid about it, especially since Audition's interface is a bit confusing. There are LOTS of things about this hobby, especially post-production, about which I'm woefully uninformed and inexperienced. Just part of the hobby game.

Quote from: china_rider on October 25, 2007, 05:54:38 AM

Whats the proper way to play with the mix here? I assume the right chan should always be inverted and the left not (unless I mess up in setting up the mics.)

There's no real proper way to play with the mix, it's basically trial and error until you find something you like. You're correct that the R channel should always be inverted, and the left not (unless you mess up setting up the mics).

Quote from: china_rider on October 25, 2007, 05:54:38 AM

Does anyone have a way they go about this to get the best mix?

It's been a while since I've used Audition, but, IIRC...

To control the amount of Mid channel in either New channel, adjust the L value. You probably want the L value the same in both New channels. In general, the more L (Mid) relative to R (Side), and the more mono the mix will sound. The more R (Side) relative to L (Mid), and the wider the stereo field will sound in the mix.

The only way to go about finding the "best mix" is to try different values for every recording, since every recording is different. I've found it's best to not judge the final mix using headphones (though for initial learning, headphones work just fine), but to get it out on my main playback system for critical listening, instead. At any rate, I usually pick a single track and generate at least a handful of options to see which sounds best, and then refine from there.

To first get an idea of how different values affect the mix, try two extremes and a middle ground:

Mono stereo field: For both New channels, set the L value to 100 and the R value to 0. The net result here is that both New channels have content from the Mid mic only, creating a mono mix.
Super-wide stereo field: For both New channels, set the L value to 0. For the New Left channel, set the R value to 100. For the New Right channel, set the R value to -100. The net result here is that both New channels have content from the Side mic only, as if you'd only run the figure-8. The New Left channel has only the positive (+) lobe of the figure-8, while the New Right channel has only the negative (-) lobe of the figure-8.
Medium stereo field: For both New channels, set the L value to 100. For the New Left channel, set the R value to 100. For the New Right channel, set the R value to -100. The net result here is a 50/50 mix between Mid and Side for each channel. The New Left channel is 1/2 Mid, and 1/2 the positive (+) lobe of the figure-8, while the New Right channel is 1/2 Mid, and 1/2 the negative (-) lobe of the figure-8.

Now, it's very unlikely you'll use either extreme as your final mix. But it should give you some idea about how changing the values impacts the mix.

I usually started off with a bunch of mixes (L value first, R value second): 100/±100 (an even mix of Mid and Side), 100/±80, 100/±60, 00/±40, 100/±20. Then I'd listen to each track to see which sounded best. If even 100/±100 didn't provide a wide enough stereo field, then I'd widen the stereo field by changing the L value to 80, 60, 40, with a lower number resulting in a wider stereo field: 80/±100, 60/±100, 40/±100. Alternatively, you could lave the L value alone and increase the R value: 100/±120, 100/±140, etc. The end result is that there's more side in the mix, relative to mid, and so the stereo field is wider.

Anyway...start off with 100/±140, 100/±120, 100/±100, 100/±80, 100/±60, and you'll hear the stereo field getting narrower as the New Right Channel numbers shrink. Determine which of these files sounds best to your ears. Then go back and try again, using the track that sounds best as your "center point" (create a few mixes both wider and narrower than the one you like best), and use smaller increments. So let's say 100/±80 sounds best to your ears. Create a new set of mixes, say 100/±90, 100/±85, 100/±80 (you already have this one, no need to generate it again, and it's your "center point"), 100/±75, 100/±70, and listen again to see if you prefer one of the more incremental changes better than 100/±80. If even 100/±60 sounds too wide (probably not, but it could), then keep ratcheting the R value down until you get close to something you like, then refine as noted above.

Over time, you'll learn what general mix sounds better in which environments, locations, etc., and you'll get faster at finding the final mix that sounds best to your ears. But there's always going to be trial and error involved.

Or...and get this...

You could just install the free Voxengo MSED plugin and use it's very simple interface, instead:

Set the Operation Mode to Decoder, then adjust the Mid and Side gain until you find a point you like. Same general process as above, but you're twisting the dials (which have values represented in dB), instead of dorking around with entering numeric values in Audition's interface. In either case, the concept, and trial and error, is the same.

Hopefully I got all that correct...

china_rider · « **Reply #40 on:** October 25, 2007, 09:33:09 PM »

Thanks for all the info. I think I have a good handle on the channel mixer now (never used it before) and I think I'm finally dialing it in. I've got a mix that sounds great on my headphones and another on my playback system. Now just to find a happy medium.

One last question, whats the purpose of inverting the new right channel?

ianstone · « **Reply #41 on:** October 25, 2007, 10:17:08 PM »

ive been wanting to run M/s now for a while, but i have been unsure that i have the correct mounts

i have the mk6 caps, which are lateral pickup. i don't really know how the fig 8 needs to be pointed although i know i want the cardioid mic pointed straight at the source.
can i do this with a vark bar?

i am thinking that the two caps should almost look like a capital "T"

with the cardioid mic being the vertical line in the T and the fig 8 being the horizontal line in the T -

or do i want them on top of each other, a la "xy" when done with the 4v's on a vert bar (with the tops of the caps almost touching)

?

Tim · « **Reply #42 on:** October 25, 2007, 10:20:00 PM »

on top of each other

card faces forward to the source and the the fig 8 lobes facing out

crude illustration of how the fig 8 should be facing
sound source ====> 8

ianstone · « **Reply #43 on:** October 26, 2007, 12:17:04 AM »

Quote from: Tim on October 25, 2007, 10:20:00 PM

on top of each other

card faces forward to the source and the the fig 8 lobes facing out

crude illustration of how the fig 8 should be facing
sound source ====> 8

awesome, i'm pretty sure i can do it with a vark bar then
thanks +T

Tim · « **Reply #44 on:** October 26, 2007, 10:09:15 AM »

+T backatcha

have fun Ian

those mk6 caps look like fun

china_rider · « **Reply #45 on:** October 30, 2007, 04:07:26 AM »

Just wanted to thank everyone for all the help. On the one was the first M-S mix I recorded that I am happy with. I'll be using it much more in the future.

I used 100/+-40 mix. Not sure if it was because of the *very* small stage (see the pictures forum) or because I was stage lip but it sounds the best combination to me over my headphones and my playback system.

http://taperssection.com/index.php/topic,93531.0.html

T+ to all in the thread.

Dana

PS. This thread has some great information. Maybe something to add to the archive?

SmokinJoe · « **Reply #46 on:** May 17, 2008, 08:14:59 AM »

Three questions:

1) I'm playing around with an Audacity Mid/Side plugin that I've never used before. I can do M/S -> XY conversion and there is a width adjustment which is nominally 1.0, adjustable from 0 to 2.0. I'm guessing 1.0 is a 1:1 mix, 0 is "all mid", and 2 is "twice as much side as mid". Can anyone confirm or deny?

2) I remember seeing a chart somewhere on the internet, here or outside of here I can't remember. It basically said something like "1:1 = XY 90*", and 1.2 ratio is like Hypers at 110*, etc. Anyone know where I can find that again?

3) There is a concept called "equivalent stereo width factor", or something like that. I can't remember the proper term so I can't google it. The idea is that the spacing and angle of near-coincident convert to a single number of equivalent width... Anyone remember what that's called?

Thanks.