Hey all,

I've been away for a long, long time (where does the time go?) and want to get back into my old hobby. I've been lurking here most of a month, trying to get a grasp on what's what and what species of lily is being gilded at the moment, and it's bewildering.

I have a Canon XL-2, CAVision matte box with two trays, bellows lens hood and rod system, a Manfrotto 503 head and either Amvona (el cheapo) CF sticks or, for brute work, Bogen 3183 sticks, an AT-825 single-point stereo mic inside an old-style Rycote WS-4, which is attached to the right-hand pan handle location using an amazing birch dowel (pat. pending).

My hobby has been railfanning, shooting trains around the Pacific Northwest. At one time I even thought I might make it a living, being on layoff, but about the same time work reared its ugly head and I went back to my day job as a machinist.

Looking at where things are today, I think I'm getting an idea of what I want as far as an upgrade to the HD world. So many things to upgrade, including audio. The AT-825 has served me very well, and the newer BP4025 would seem the logical upgrade unit. But I've been reading about M-S stereo, and now I only know just enough to be a hazard to my own judgement. I know the advantage to it as far as having an honest interview mic (not that I've ever done an interview) but the concept of spacial manipulation interests me.

Is it worthwhile to go the M-S route for my application? I was thinking of a pair of AKG Blue-line mics, using the CK94 and CK-93 and a Rycote WS AE kit. It's much pricier than the BP4025, but I was going to replace the WS-4 with a WS-3 anyway. The specs of A-T's BP4025 are very attractive, and the old AT-825 has been an amazingly sensitive, quiet, and forgiving mic. I'd be rather concerned about dynamic range and max SPL: wheel flange squeal will loosen one's teeth, I kid you not.

BTW, some years back I thought the Rode NT-4 was the bomb due to its specs. Well, the one I had was a bomb, so much so that I have zero interest in their product line. Maybe it was a factory reject that made it to market or maybe somebody damaged it and it was returned. Horrible device, yet all I read are lauds?

I prefer XY rather than MS, sorry to hear your experience with the NT4 was not good, I personally love the results it gives for location stereo.
If you do use MS and are going down the unmatrixed form be VERY careful that everyone that can edit / change / mix / have access to it fully understands MS and its pitfalls. If someone is unaware that it is MS they can destroy a mix very rapidly.

Perhaps a bigger decision for stereo sound with pictures should the sound image pan with the picture image OR should the screen be regarded as a window (like a house) and any sound image should move across it.

Some of the older MS mics were capable of handling VERY high SPL's ie; Sony ECM 969 were often used for grand prix cam FX mics..... BUT they had a very poor s/n ratio, great for car racing but poor for general FX recordings.

Doug, I regularly use the BP4025 with pleasure. Most reviews hail it as a superb mic for recording ambiance, e.g., in nature. I don't disagree. Indeed, it is an astonishingly quiet mic and, paired with my Sound Devices 302 with its quiet preamps, it will yield a freaky quiet, beautiful stereo image.

Its 1" LDC capsules are fixed at 120*, IIRC, so the stereo image is wide. Anything close might sound a little weird.

I used it once to record scratch audio at a very loud rock concert using the 10 dB pad. It performed flawlessly. No distortion.

Audio guru Ty Ford, who chimes in here from time to time, once wrote an exemplary review of this mic; it nudged me toward a purchase. I can't seem to find a link at the moment.

Hope this helps.

Caveat: While my 'profile' states 'Major Player', it's merely a function of quantity of threads I've commented upon. I'm not an expert!

It would be helpful if you could let us know what you're planning to record? I've always been told dialog should be captured in 'monaural' and 'Nat Sounds' (background) in stereo. That said, if you're planning to record chamber music in an acoustically clean environment, one of the numerous X/Y, M-S, Decca Tree, Blumlein Array, etc., would be some of the microphone configurations you can experiment with. Remember, the 'audio string' begins with the microphone. GIGO.

I'm sure some of the real audio experts will chime-in and provide more detailed and substantive information.

Regards,

J.

I have assumed trains.... Original post 3rd paragraph

OP: "My hobby has been railfanning,..." Past tense? Maybe I read too much into it?

J.

(Assuming this _is_ railways/railroads...)

Hmmm. I do a lot of railway videos. I am not an audio expert by any means, but I get by, and have more direct experience of recording steam and diesel locomotives than a lot of people on here I'd guess.

I've always used mono shotgun mics, currently a pair of AT875R microphones. Cheap and cheerful, Nattrass Approved(TM) and great shotguns. One of them is camera mounted, and the other lives inside a Rode Blimp and is operated by someone else, recording into a Tascam DR-60. If a train is passing by, you just pan the mic along with it and you get pretty good sound. Trains are loud beasts, and you don't need to be within a foot of the subject like you do for voice recording. I can be 100s of yards away across a beach, field, hilltop etc. and still get great sound.

Results are pretty good, I have to say. Occasionally I do a pan in post to simulate stereo on cliched shots of a train passing at distance from the camera, but normally it's just mono. And nobody notices.

I did dabble with a similar AT8022 X/Y stereo microphone. It's great for music, ambient etc., and I've kept it for this purpose. If you go into a forest or other environment, or a music performance of some sort, the ambient recording is just excellent.

But it's total pants at recording "trains through the landscape", as it's just too quiet until the train is almost upon you. You either have the mic mounted, static, pointing in the mid-point of the pan (for example), and you only get any meaningful sound when the train's really close. Or you pan it with the camera, and it just sounds weird, but still way too low volume to be of any use.

It's not a levels setting or anything like that. It's just not the mic for the job of recording a distant sound getting closer then passing. At least, not for me. Of course, the BP4025 could be way better than the AT8022. I just don't want to waste £500 finding that out! I would love to hear any advice from people with actual experience of recording trains in this way.

I really would suggest that music in an auditorium or studio etc. is very different from recording this sort of subject, and should not be taken as a recommendation that the same mic works in train audio recording. The AT8022/BP4025 would be great if you had it strapped to the train to get good engine noise, but I think that's as far as I would go.

One thing I do take comfort in is that nobody has ever, ever complained about my sound - and sound is super-important for train people, take my word for it! The only issue I've ever had is wind, I do end up in some really gusty locations, and at times even the Rycote S-Series windshield isn't enough.

As I said, specific advice in this recording field would be very welcome!

Mike, I enjoyed watching a few of your train videos. I noticed (from my very small sampling) that you're performing simple pans, L-R or R-L, and, hence, I can appreciate your remarks on using a camera mounted shotgun. Yet, what about recording a train through a proper stereo mike on a field recorder located close to the tracks, you and cam at a distance, then sync in post?

I don't know much about trains!

But someone has to step in to promote M-S! I use M-S regularly for ambience recordings of various types, in many cases this is the room sound to mix with direct microphone sources for music. Have I made that clear as mud? I do a fair amount of live sound work with multitrack recording, and a stereo mic in the audience really brings these recordings to life. Even more if the "audience" is singing along...

Also have done quite a bit of recording/video of acoustic music, using a single M-S, or an ORTF or X/Y array.

These days, it's mostly M-S, for the convenience of the single mic body (ORTF and X/Y with two cardoids), and the magic of dialing the stereo spread.

Have done quite a bit with a friends Beyerdynamic M-S, a beautiful mic, but unaffordable for mere mortals. I purchased a Nattrass Approved (TM) Sony MS-957 a few years ago, and it has been a workhorse. It decodes to stereo in the mic, so dialing the spread in Post is somewhat more involved, but can be done by dematrixing the stereo back to M-S. Quite possible with a bit of headscratching.

I like M-S! One of the advantages is an absolutely seamless degradation to mono. There's an involved explanation to why this is so, but the short story is that when left and right are summed to mono, what you're left with is the signal from the cardoid that supplies the "mid" signal (M-S = Mid-Side), with no potential for comb filtering or other phase artifacts, such as you get with X/Y, or even moreso with ORTF.

On the other hand, in my practical experience, the phase artifacts so often referenced in summing X/Y or ORTF to mono don't seem to sound bad to me on good monitors, even though the math predicts horrible results.

My all-time favorite stereo image is ORTF. But the convenience of a single M-S mic wins in most of my shoots, with ORTF coming out for small acoustic performances direct to stereo.

A train is not a singer/songwriter... but I'd be interested to hear comparisons of these different stereo techniques with the train. Get yourself a couple of mic bodies, a pair of cardoid capsules, a figure-8 cap and a mounting bar, and you can try them all!

The conventional wisdom is that stereo be done with a fixed mic/array, not panning. But we all swivel our heads with the train, why not pan the mics too?

Mike Beckett, above, writes about how the distant train was inaudible using a stereo mic until it was quite close. I'd try to find a valley with road crossings - the valley echoes the sound of the train, the road crossings so as to hear that magnificent (steam?) horn. Record the sound at 3am when other sources are quiet? This would allow boosting the gain in recording and/or post with less general background sounds. Put this alongside some daytime video...

Steven,

Thanks - I did try that, but the problem is you really don't hear much until the trains it's on top of the mic. I will always use off-camera audio where I can, for wind protection and not removing risk of camera rattles such as buttons being pressed or my feet crunching in gravel.

Because a shot tends to last quite long, a close-up mic would not capture very much sound. I did once think off putting a whole series of audio recorders along a site, but I'm not made of microphones or money!

Seth,

great suggestion - I could absolutely experiment more, but I'm very limited in locations in this country, so the valley idea is out. Not much happening at 3am really either :) The things I film are rare/one-off movements, so it's hard to record sound from other times. I have dubbed sound sometimes, and nobody has yet noticed, not even the most die hard train nerds!

The problem with this sort of thing is the distance from the sound source to the microphone, as well all know there's no such thing as a zoom microphone.

I don want to hog this thread too much though, I defer to the OP who may or may not have the same questions/issues as me.

Is it worthwhile to go the M-S route for my application?

Depends (of course).

I'm certainly not an expert. And it's been awhile since I studied this stuff. But what I remember is that mid-side works by eliminating phasing. The stereo image is formed solely by loudness variation. And this in turn lets you decide how wide to make the stereo separation in post when you do the decoding of the two mic tracks to stereo. That convenience is a big attraction and part of the reason for mid-side's continuing popularity. That, and it sounds quite good.

Mic systems like x-y and ORTF capture the phasing information. Because the stereo field is in part dependent on the phase differences, the width of the stereo field is defined at capture time. So you have to be spot-on in mic placement at capture since you aren't going to materially effect the stereo field in post. What you supposedly gain by giving up this flexibility is better stereo imaging and "a more natural sound".

In reality, people turn this into a religious argument. It comes down to mid-side having its adherents, and x-y (and the variations) having its adherents. Which side you decide to join is a personal decision. The only help I can give to someone trying to decide is the advice to try recording and listening to both. Trust your ears, trust your instincts. You'll make the right decision, for you.

If you are doing ANY production that is in stereo.... it doesn't matter if its XY / MS / AB / ORTF or any other form ALWAYS check the mix in mono as well........ALWAYS ....NO exceptions !!!!!!!!

Another M-S Fanboy here!

I use it a lot for orchestral recordings and vary the M mic according to what sounds better - omni works fine for quite a lot of things things.

I will say that I like X-Y beter for acoustic guitar and it's a toss-up for classical piano. Of course you could write a thick book about mic-ing the piano.

I use a pair of Schoeps mics into a Sound Devices 302/702 and have never gotten any complaints about sound quality.

Would like to try ORTF but just haven't gotten around to it yet.

Never done trains though.

A high-quality X-Y stereo mic is most likely best for the OP's application. High-quality portable preamps are also a must. Setting up a multi-mic array takes time, skills and is a PIA to lug around.. to remote locations.

Thanks for the replies, fellows. I responded to this thread many hours ago but my post was lost (took too long to type it, I reckon).

I think I'll stick to the single-point stereo mic like the A-T BP4025. While it isn't as sensitive as the AT-825, the other specs make for a very attractive mic. For my part, I do love to capture the ambiance of the location, whether it be wind rustling the leaves or sighing through tall grass and sage, birds or babbling brooks, or roaring rivers and falls, I believe that a sonic picture is worth detailing.

I'm a bit puzzled as to what separate pre-amps would bring to the package. I've never had trouble with the camera's own. Well, except very early in my experience, in the mid 90's when I had a consumer Hi-8 thing. I was at a profoundly quiet place, almost anechoic, and wondered what I was recording.

I was recording HISS, that's what. Bands of it at about 15KHz which, I'm sure you'll recall, was the limit of Hi-8 AFM. I created an FFT filter in post to mask it. Haven't troubled to do so in the digital age, but I do normalize the sound levels in post. That's it. Keeping it simple and stupid. So, in other words, for HISS to KISS, ha ha!

If you are doing ANY production that is in stereo.... it doesn't matter if its XY / MS / AB / ORTF or any other form ALWAYS check the mix in mono as well........ALWAYS ....NO exceptions !!!!!!!!

I'll bite -- why? In particular, if it's never going to be heard in mono, why check in mono?

I'll bite -- why? In particular, if it's never going to be heard in mono, why check in mono?

You can never asume that something may never be heard in mono especially for broadcast and if the capsules are out of phase they will cancel out.

I personally prefer using a stereo M/S mic on location but recorded as a matrixed A/B signal as the M capsule is always pointing at the sound source.

I'll bite -- why? In particular, if it's never going to be heard in mono, why check in mono?Because a lot of your listeners will actually hear it in mono.

I'll bite -- why? In particular, if it's never going to be heard in mono, why check in mono?

A lot of recorded material gets played as mono... many YouTube clips are mono (phones and tablets) even some laptops have problems.
Subwoofer (low frequency material ) is played as mono, even wide screen TVs have subwoofer systems in them.
Theatre / stage shows / productions are mono.
MP3 / MP4 files often have poor channel separation at lower frequencies, resulting in virtual mono results.
PA systems are mono.

SO if you use a bad mic setup like 'over wide MS' or poorly aligned XY phase errors WILL occur, this will result in frequency cancellations in your mix / recordings.

So if your recordings / mix EVER ends up on YouTube, mobile phones, tablets, laptop computers, Broadcast, PA, DVD's, Theatre, or played on a big screen make sure that you have correct phase correlation......

Hence my suggestion to use a single 'stereo' mic which should be mono compatible w/o alterations. But I would check mono compatibility anyway.. via listening to L+R summed AND a scope.

...SO if you use a bad mic setup like 'over wide MS' or poorly aligned XY phase errors WILL occur, this will result in frequency cancellations in your mix / recordings...
This is not correct. MS, whether mixed "overwide" or narrow degrades to perfect mono. Stereo information from the left perfectly cancels the stereo info from the right channel when summed to mono, and what remains is center (the Mid mic). Now, if you were using an M-S mic as your only source, then mixed the Mid channel down to zero, you could end up with very little gain when your stereo mix is summed to mono. But I've never been tempted to do so when mixing M-S... because the process is to dial the stereo spread to taste, and it always sounds best with a significant amount of mid gain.

You'd have to go way past "overwide" before you lost significant gain on summing L+R to mono...

A "poorly aligned XY" array becomes a near-coincident pair, rather than the coincident pair that you're supposed to use with this technique and a pair of mics. You could describe ORTF as a poorly aligned XY, or even look at AB that way. Phase errors will occur, yes, but what is the audible result of this? I recommend listening, trust your ears!

But, as Brian and many have pointed out, checking out how your mix sounds in mono is really a best practice no matter what stereo techniques you might be using.

Sorry to go into rant mode here, but the way that MS works in mono is a strength of the technique, not a weakness. Granted it is possible to screw it up...

The best way to screw up mono compatibility is to have a phase problem in your monitoring, do pay attention to polarity all the way from your sound card to the monitors and get it right! Likewise, in any playback system.

Check all mixes in mono all the time. X-Y, A-B, ORTF, and yes M-S too can all be screwed up if you're not careful.
Hence my suggestion to use a single 'stereo' mic which should be mono compatible w/o alterations. But I would check mono compatibility anyway.. via listening to L+R summed AND a scope.
Well... I've had a lot of fun with two cardoids in X-Y and ORTF, and the mono didn't sound bad. The conventional wisdom is as Rick says here... but... unless screwed up in some other way, even ORTF, which the engineering math says should have the greatest phase "errors" can sound fine in mono, in my personal experience.

There are some accepted truths in this business that are worth testing for yourself! The theory behind phase cancellation and comb filtering is solid, it's good engineering and math, but in practice it is not so cut and dried, everything seems to be a lot looser when you have microphones in real spaces with real sources... in my experience.

If it sounds good, it is good - was that Count Basie or Duke Ellington?

Seth.... have you ever broadcast MS mics LIVE to air?

I did a golf tournament in the early days of stereo TV using MS mics, to match some of the wide pretty shots we set the stereo mics to wide (nothing tricky JUST the 'wide' setting on the mics).

It went like this.... program open music xfade to stereo FX (wide MS mics) for 10 seconds to established the location, cue commentary..... BUT what occurred at ALL the transmission station(s) across the country was the auto phase correction detected an out of phase signal so it corrected it and phase inverted R channel to bring it into 'what it assumed as correct phase', and when the commentary started the mono commentary was completely canceled out.......... YEP thats right NO commentary across the country..... and ALL caused by some MS mics set to the wide setting on the mic.

So don't tell me there is NO problems with MS mics !!!!!!!!!!!!!!!!!!!!!!!

Since that incident many years ago I now use XY set VERY wide almost to a point of having a dip in the centre of the audio image, the mono commentary and spot FX sits in there nicely giving a VERY wide spatial sound image that suits wide screen TV fantastically.
This XY stereo technique is what I have used for the past 25+ years in live to air sporting Outside Broadcasts.

And thats why I have ALWAYS said that EVERYbody that has some ability to change the sound of a mix MUST be aware of how MS works and how it can be used and more to the point how it can destroy a Broadcast....
If you ever do a movie or music record using wide MS how do you know what will occur to the material you have created many years down the track...Could you be creating future problems for others?

With best respects Brian that is a problem with the transmission system and not a problem with M/S mics.

If networks chose to put auto phase correction across their output that is not my problem as a sound supervisor if I am sending a valid stereo signal.

I appreciate what you are saying but if that was the case then pretty much every dolby pro logic mix that has ever been done would cause the same problems so it is not specifically an M/S mic problem.

For a moving object against a stationary background, although I don't use it much myself, I'd go the M/S route on this one, because of the complexity of the moving sound source. For a passing noise like maybe a Police siren, X/Y or even a spaced pair of omnis would be nice, for the passing object that has extreme length, like a train, M/S offers a more suitable recording method. Not so much for the actual stereo image, but the possibilities of controlling it afterwards. The only issue with M/S is when post is carried out by people who don't understand how it works.

Hey all,

I've been away for a long, long time (where does the time go?) and want to get back into my old hobby. I've been lurking here most of a month, trying to get a grasp on what's what and what species of lily is being gilded at the moment, and it's bewildering.

I have a Canon XL-2, CAVision matte box with two trays, bellows lens hood and rod system, a Manfrotto 503 head and either Amvona (el cheapo) CF sticks or, for brute work, Bogen 3183 sticks, an AT-825 single-point stereo mic inside an old-style Rycote WS-4, which is attached to the right-hand pan handle location using an amazing birch dowel (pat. pending).

My hobby has been railfanning, shooting trains around the Pacific Northwest. At one time I even thought I might make it a living, being on layoff, but about the same time work reared its ugly head and I went back to my day job as a machinist.

Looking at where things are today, I think I'm getting an idea of what I want as far as an upgrade to the HD world. So many things to upgrade, including audio. The AT-825 has served me very well, and the newer BP4025 would seem the logical upgrade unit. But I've been reading about M-S stereo, and now I only know just enough to be a hazard to my own judgement. I know the advantage to it as far as having an honest interview mic (not that I've ever done an interview) but the concept of spacial manipulation interests me.

Is it worthwhile to go the M-S route for my application? I was thinking of a pair of AKG Blue-line mics, using the CK94 and CK-93 and a Rycote WS AE kit. It's much pricier than the BP4025, but I was going to replace the WS-4 with a WS-3 anyway. The specs of A-T's BP4025 are very attractive, and the old AT-825 has been an amazingly sensitive, quiet, and forgiving mic. I'd be rather concerned about dynamic range and max SPL: wheel flange squeal will loosen one's teeth, I kid you not.

BTW, some years back I thought the Rode NT-4 was the bomb due to its specs. Well, the one I had was a bomb, so much so that I have zero interest in their product line. Maybe it was a factory reject that made it to market or maybe somebody damaged it and it was returned. Horrible device, yet all I read are lauds?

MS definitely.

The coincidental mics are much easier to windshield, direct and control than an XY pair.

I never use XY nowadays - if it's not MS, then I use ORTF or spaced omnis - but for whhat you suggest, then MS is definitely the best option.

My MS rig is Sennheiser MKH 40/30 and I have two of them.

If it sounds good, it is good - was that Count Basie or Duke Ellington?

Ellington, one of my heros. Usually written as "If it sounds good, it IS good."

... mobile phones, tablets, laptop computers, Broadcast, PA, DVD's, Theatre, or played on a big screen make sure that you have correct phase correlation......

Hadn't thought about the small handheld devices. But the audio is so bad on those things that it would probably be difficult to hear any sound problems with them anyway. Still, something to think about.

Seth.... have you ever broadcast MS mics LIVE to air?

I did a golf tournament in the early days of stereo TV using MS mics, to match some of the wide pretty shots we set the stereo mics to wide (nothing tricky JUST the 'wide' setting on the mics).

It went like this.... program open music xfade to stereo FX (wide MS mics) for 10 seconds to established the location, cue commentary..... BUT what occurred at ALL the transmission station(s) across the country was the auto phase correction detected an out of phase signal so it corrected it and phase inverted R channel to bring it into 'what it assumed as correct phase', and when the commentary started the mono commentary was completely canceled out.......... YEP thats right NO commentary across the country..... and ALL caused by some MS mics set to the wide setting on the mic.

So don't tell me there is NO problems with MS mics !!!!!!!!!!!!!!!!!!!!!!!
...
If you ever do a movie or music record using wide MS how do you know what will occur to the material you have created many years down the track...Could you be creating future problems for others?
Brian, that's about the biggest broadcast sound nightmare I've heard of. I'm sure the recollection comes with some pain.

My broadcast TV days were pre-stereo... but I also had some problems with the processing done downstream of my console. The guy who trained me always listened to the transmitter return, because the compression/limiting done in Master Control was seriously screwy, and if I wanted the folks at home to hear a reasonable mix I had to monitor post of that processing. I got a rather serious dressing down after it turned out that the feed to cable distribution occurred pre of that processing, and the cable subscribers were hearing levels all over the place. The resolution was to make the (pre) air tape mix sound good, then management would be happy. "Sorry" to the broadcast viewers at home.

You know, the real problem was the compression/limiting setup done by transmitter engineers who had no f****ing idea what they were doing with sound.

I have to agree with Mr. Nattrass, above... though that's small comfort when management comes down on YOU!

One can hope that the days of auto phase "correction" without human intervention are gone, you'd think there would be all sorts of contemporary pop music that might trigger it, but probably the tradition continues somewhere. Presumably with a strong Mid signal in the mix it wouldn't happen. What mics were these?

BBC, on the other hand, mandated that all atmos / ambience be acquired in M-S, because of the graceful sum to mono. Don't know if that mandate is still part of the programming spec (I'm in the U.S.), but it was true for many decades.

But I hear your criticism, and I've been caught in the trap I pointed out earlier in this thread - there is theory, and there is experience. We need to have our practice informed by both. And though I'm a huge fan of M-S, if it ever comes up that my work might make it to Australian broadcast, I'll keep what you wrote in mind!

There's only so much I can do to prevent problems down the road; it really isn't my responsibility to think about every possible future screwup, only the common ones. My real responsibility is to my employer-of-the-moment; the best practices that will support their goals.

BBC, on the other hand, mandated that all atmos / ambience be acquired in M-S, because of the graceful sum to mono. Don't know if that mandate is still part of the programming spec (I'm in the U.S.), but it was true for many decades.


Many years ago I came across a copy of those BBC requirements in an old file.... BUT the other thing that was also mentioned that it needed to be recorded 1/4" tape @ 3 3/4ips or 7 1/2ips..... NOTHING else would be accepted. 1/4" @ 3 3/4ips Mono was the standard for voice.

At the time I would assume it would have been the logical choice otherwise location sound guys would have used crossed pairs of MKH816's.... AND the post production guys then would have been attuned to working in MS, these days people don't understand the technique let alone be attuned to using it.

The automatic phase error problem was perhaps not the 'fault' of M/S but of the use of M/S mics that do the re-matrixing in the mic - as in without any attempt to listen to the recombining. Gary has one of the Sony mics that do this, but the width adjustment must be listened to - or the left to right differences can be extreme - especially when presented with a dead centre component in the sound field.

I suspect this just emphasises that there is is no 'correct' technique, just ones that are appropriate on a case by case basis.

I also had an ABW (AB wide) on the AMS Neve logic and DFC consoles I used for many years and you could change the width of any XY or M/S signal to suit when mixing in Pro Logic but as others will know all too well you have to be careful or the compliance police will reject the content for being out of phase and I have had many an argument with some graduate who looks at a chromatec phase meter rather than doing a proper mono check!

One stereo trainer from ravensbourne (Neil Papworth?) once summed up phase meters wonderfully by saying that they wave at me and I wave back at them! ;0)

I would never record M/S though as there are too many problems and people who do not know what to do with it and if you lose the left M channel you are pretty much stuffed, I also knew an editor who did a whole conform with just the S channel and wondered why it all sounded a bit distant but I have used those sony prosumer M/S mic's the 907 and 957 for many years to record stereo sound effects for film and TV.

Audio guru Ty Ford, who chimes in here from time to time, once wrote an exemplary review of this mic; it nudged me toward a purchase. I can't seem to find a link at the moment.

Hope this helps.

Hello Steven and thanks for the hat tip.

The BP4025 is the upgrade. I may have moved the audio file to a new location on my server.

It's now here: https://www.dropbox.com/s/7f0qg6se5bzvbev/ATBP4025ambi08.wav


BTW, as it was explained to me, the beauty of the Mid/Side method is that, during production, you can never know when you'll use the wide or closeup shot. Their thought was that being able to vary the stereoscape in post production would be of value. I haven't done any experiments with that to really get a feel of how it might affect the shot. Maybe it's very valid, maybe it's a "because we can" situation.

I was told some years ago that in France, shooting dialog in Mid/Side was popular for similar reasons. I don't have any data on that either, but shooting dialog in Mid/Side sounds like a lot of precarious work if you're doing it with the thought of using the wider settings during a mix.

Regards,

Ty Ford

And, after digging around a bit, I found the original review.

Ty Ford Audio and Video: Audio-Technica BP4025 Stereo Mic - In A Field Of Its Own (http://tyfordaudiovideo.blogspot.com/2013/09/audio-technica-bp4025-stereo-mic-in.html)

Regards,

Ty Ford

Seth.... have you ever broadcast MS mics LIVE to air?

I did a golf tournament in the early days of stereo TV using MS mics, to match some of the wide pretty shots we set the stereo mics to wide (nothing tricky JUST the 'wide' setting on the mics).

It went like this.... program open music xfade to stereo FX (wide MS mics) for 10 seconds to established the location, cue commentary..... BUT what occurred at ALL the transmission station(s) across the country was the auto phase correction detected an out of phase signal so it corrected it and phase inverted R channel to bring it into 'what it assumed as correct phase', and when the commentary started the mono commentary was completely canceled out.......... YEP thats right NO commentary across the country..... and ALL caused by some MS mics set to the wide setting on the mic.

So don't tell me there is NO problems with MS mics !!!!!!!!!!!!!!!!!!!!!!!

Since that incident many years ago I now use XY set VERY wide almost to a point of having a dip in the centre of the audio image, the mono commentary and spot FX sits in there nicely giving a VERY wide spatial sound image that suits wide screen TV fantastically.
This XY stereo technique is what I have used for the past 25+ years in live to air sporting Outside Broadcasts.

And thats why I have ALWAYS said that EVERYbody that has some ability to change the sound of a mix MUST be aware of how MS works and how it can be used and more to the point how it can destroy a Broadcast....
If you ever do a movie or music record using wide MS how do you know what will occur to the material you have created many years down the track...Could you be creating future problems for others?

This does not sound like an MS problem per say, but it sounds like that the raw MS was transmitted instead of being matrixed to left/right stereo.

This would be a finger problem at source by someone not understanding how MS should be handled.

The mic used was NOT in an unmatrixed form, the Sony ECM 969 does NOT have that option...
I have demonstrated the effect on many MS mics, Sony MS (various models) Shure VP88, Audio Technica, AKG etc to other sound professionals from film / TV broadcasting. They were unaware of the potential problems of wide MS.....They are now!!!

While I have to agree with others it's not the direct fault of a MS setup.... YES it's an operator fault BUT if the settings appear on the MS mics people will use that setting.

MS technique gets discussed frequently on forums by people that have little knowledge on the subject and these are the exact people will obtain a MS mic set it to wide thinking it will be OK...... well under some (I admit very rare and very specific) situations the MS technique can cause problems, this needs to be kept in mind because some people on various forums promote the MS technique as 'the perfect STEREO' setup.

In an unmatrixed form the potential of problems has vastly increased if it's used by people with minimal knowledge on the subject of MS, this is why I have always said that ALL people in the production process that use MS should be FULLY aware of how its done / used / and its pitfalls.

I have a HDX-900 with an AT835ST as an on-board mic. I keep it in M-S mode, so when I switch a channel to use a wireless mic, I still have the M channel as the camera mic. If I had the 835 in X-Y then a single channel would be listening off to one side. I agree it's very important to make sure the editor knows that I've recorded M-S, and knows how to deal with it.

By the way, there are any number of plugins that will translate stereo to M-S and allow spread adjustment and translate back to stereo.

Giving a video editor M-S tracks to 'mix' is a disaster waiting to happen. An experienced audio post engineer is another story.

Giving a video editor M-S tracks to 'mix' is a disaster waiting to happen. An experienced audio post engineer is another story.

Amen to that and I think I said before I had one editor do a whole show with just the S track and wondered why it sounded very distant, it is always why I never ever record in M/S!

It should be mentioned that many better field mixers allow one to use M/S micing with the matrixing to L/R stereo done in the mixer for output.

Brian's comment about the golf match is interesting.

Brian, am I understanding you correctly, they went to air with raw M/S?

Regards,

Ty

Ty I think Brian meant that an M/S source mic was matrixed very wide so the S content was greater than the M so it would look out of phase as a stereo signal.

I have had this happen a lot when mixing pro logic and using the AMS Neve AB-wide control to increase the S content but it then makes a phase meter on a chromatec go negative.

I have never heard of automatic phase flippers though and all I ever got was a phone call from an inexperience QA person who didn't understand phase meters or how pro logic mixes can cause this and once I tell them to check the mono mix all has been OK.

Great discussion guys!

For Seth & Gary: I have a Sony ecm-680s Shotgun stereo mic in which the capsules are in m+s mode. However there is a chip in the mic that switches the signal to L+R stereo encoding for input to the camera. What can be done in post to get the M+S signal back?


Thanks in advance

... However there is a chip in the mic that switches the signal to L+R stereo encoding for input to the camera. What can be done in post to get the M+S signal back?
By the way, there are any number of plugins that will translate stereo to M-S and allow spread adjustment and translate back to stereo.
I'd be interested in Jim's recc for a plugin, but here's how I did it.

Matrixing M-S to Stereo looks like this:
L = M+S
R = M-S

Think about how you'd set that up on a timeline: A single M track panned center, an S track panned hard left, and an inverted S track panned hard right. Group the two S tracks, and adjust the gain between this group and the M track to find the spread and image you want.

So, remembering algebra, if we use the math to de-matrix from Stereo to M-S, it looks like this:
M = (L+R)/2
S = (L-R)/2

Have I got that math right? If so, to set up on a timeline, you'd split your L+R file into two tracks, the method differs between NLEs/DAWs. Pan each track center and render; that's your M clip. Now, invert the phase of the right track and render, that's the S clip.

(We've ignored the "divide by 2" step in deriving our M & S, but do make sure you're not overmodulating the renders, you might need to reduce master gain before rendering.)

You've dematrixed, now start a new project and set it up as above, L=M+S, R=M-S and dial your spread!

With some judicious grouping, you can do it all on one timeline, the dematrix and new matrix back, but that gets needlessly complex, too easy to make a mistake, I recommend rendering as above.

Why do it the easy way with a plugin? This is so much more fun, and better learning, too! But after you've done it once and said "isn't this cool" you could go right to using a plugin... you'll know what it's doing.

(Won't my ears be red if I've flubbed the math, it's been a few years since I dematrixed, and a few decades since Algebra!)

Brian's comment about the golf match is interesting.

Brian, am I understanding you correctly, they went to air with raw M/S?

Regards,

Ty

No Ty, it was a L / R FULLY matrixed output but the width setting was on the widest it would go (the mic used Sony ECM969 did NOT have an un-matrixed [raw] MS output).

The width setting controls change the ratio between M and S components, in the wide setting there is more S component than M component making the audio image very wide .... But if there is a sound (bird call, frog croak, car horn etc or any other sound) at 90deg to the mic on either the left or right it WILL result in an out of phase signal on the other side..... and if that sound is there long enough it will be regarded as being 180deg out between L & R and in a broadcast chain will possibly cause errors when going to air depending on the transmitter processing.

And its NOT just Sony mics that do this, I have been able to replicate the problem on ALL MS mics I have had acess to Shure VP88, Audio Technica [various models] , AKG and Sony [various models], I haven't tried the Sennheiser 418 but I am assuming it would be similar to other mics.

edit... Just checking the details on the Senni 418 it appears to be an UN-matrixed mic and ONLY has a discreet M and S outputs and NO Left / Right outputs.

Great discussion guys!

For Seth & Gary: I have a Sony ecm-680s Shotgun stereo mic in which the capsules are in m+s mode. However there is a chip in the mic that switches the signal to L+R stereo encoding for input to the camera. What can be done in post to get the M+S signal back?


Thanks in advance

Voxengo MSED Audio mid-side encoder-decoder plugin (AU, VST) - Voxengo MSED - Voxengo (http://www.voxengo.com/product/msed/) is the tool I've used.

Fran

I now use this free plug in for Pro Tools to adjust the M/S width of an A/B signal in post:

Brainworx | bx_solo (http://www.brainworx-music.de/en/plugins/bx_solo)

This may also help people new to the M/S technique: http://www.brainworx-music.de/en/whatisms

I've also used it as well as Waves SI - both work just fine IMHO

No Ty, it was a L / R FULLY matrixed output but the width setting was on the widest it would go (the mic used Sony ECM969 did NOT have an un-matrixed [raw] MS output).

The width setting controls change the ratio between M and S components, in the wide setting there is more S component than M component making the audio image very wide .... But if there is a sound (bird call, frog croak, car horn etc or any other sound) at 90deg to the mic on either the left or right it WILL result in an out of phase signal on the other side..... and if that sound is there long enough it will be regarded as being 180deg out between L & R and in a broadcast chain will possibly cause errors when going to air depending on the transmitter processing.

And its NOT just Sony mics that do this, I have been able to replicate the problem on ALL MS mics I have had acess to Shure VP88, Audio Technica [various models] , AKG and Sony [various models], I haven't tried the Sennheiser 418 but I am assuming it would be similar to other mics.

edit... Just checking the details on the Senni 418 it appears to be an UN-matrixed mic and ONLY has a discreet M and S outputs and NO Left / Right outputs.

Thanks Brian, got that and yes, in the 418S, the side capsule is behind the mid capsule. So any time you get 90 degrees off axis, the sound is impinging on both capsules simultaneously. If any of that sound comes in more than 90 degrees off axis, the stereo image wobbles. I've found a wobble point on both sides of an M/S capsuled mic (specifically M/S mics that have the Side capsule behind the Mid capsule) as the sound source goes behind the mic on one side and comes back on the other.

Regards,

Ty Ford

Here is a comment made by another person that also used MS.....
And this is why I have been saying that MS is NOT a foolproof system, It MUST be used with care.
What would have been the expense been if many thousands of CD had been produced and the client had rejected the mix?