M-S vs. X-Y for field use

[Brian P. Reynolds]

I would have to agree Gary, how many times has the subject come up about 'what is the best camera mic for recording dialogue' or 'what is the difference between mic and line level'
For many DSLR users and low end videographers audio seems to be a stumbling block.

I still believe that MS is beyond the capabilities of many video production people.....even rolling off the bottom end or using a HPF in the editing process is to much for some people.

[Gary Nattrass]

Even with digital recording meaning that M/S as a source can be recorded and handled more accurately than with analogue and it's inherent phase and combing I know of several location recordists who did not understand the post processes involved and have made huge mistakes recording M/S on location so to expect a videographer to handle it is asking far too much.

Even I have never recorded M/S in over 33 years but have used the mic technique and always with an M/S designed mic that outputs A/B.

You can use the M/S encoding technique Paul highlighted but it is hugely level critical and you can collapse or over anti phase the resulting signal very easily, I personally have always had AMS Neve Logic or DFC digitall consoles with AB-wide contraols but as most location recordists don't even bother to ident what is dual mono. M/S, A/B or radio mic and boom it tends to be impossible to handle recorded M/S in post and certainly most editors will not have a clue what is going on.

Now for static orchestra or ensemble recordings it may be easier but for me I would still be going for an A/B recording from an M/S mic but may put an M/S signal on a spare couple of tracks if I had them available.

[Mark Fry]

Originally Posted by Mark Fry

I've also got to work out what I'd have to do in my NLE (Avid Liquid 7.2) to mix M/S on the time-line. It certainly doesn't have any pre-set for it, so I'd have to "roll my own". I'm not even sure if it can invert an audio track. If it can't, then choosing a mic is a bit academic. OTOH, it will be an interesting question to ask when choosing my next NLE (since AL is obsolete now).

The bad news is that AL can't invert an audio track. However, it can accept VST plug-ins, which I'd forgotten all about (a legacy of the brief period when Pinnacle owned Steinberg, before selling them on to Yamaha). This means one can either use a simple mono inversion plug-in on a copy of the Side track, or use an M-S processing plug-in (e.g. Voxengo MSED). There seem to be quite a few alternatives, most of which are free. I've not actually tried any yet so I don't know which ones might be good, bad or indifferent, but at least I should be able to do it with Liquid. Hooray for open interface plug-ins! Anyone tried any of these VSTs, and got any personal recommendations, pro or anti?

[John Willett]

Originally Posted by Gary Nattrass

With best respects John a great deal of the video camera and DSLR users are not full audio engineers and I would think they would struggle with a full M/S rig as a rode videomic or an NTG2 is their level of mic kit.

When I started recording with MS I was certainly not a "full audio engineer" - I was a lad recording for a hobby in my spare time and learned by experimentation and reading magazines. I had no training at all.

As a novice, I found it very easy to pick up.

Are videographers really so stupid that anything slightly technical stumps them completely?

I think not - I certainly hope not - otherwise they would never be able to operate the camera, which is a lot more complicated than simple MS recording.

[John Willett]

Originally Posted by Mark Fry

The bad news is that AL can't invert an audio track. However, it can accept VST plug-ins, which I'd forgotten all about (a legacy of the brief period when Pinnacle owned Steinberg, before selling them on to Yamaha). This means one can either use a simple mono inversion plug-in on a copy of the Side track, or use an M-S processing plug-in (e.g. Voxengo MSED). There seem to be quite a few alternatives, most of which are free. I've not actually tried any yet so I don't know which ones might be good, bad or indifferent, but at least I should be able to do it with Liquid. Hooray for open interface plug-ins! Anyone tried any of these VSTs, and got any personal recommendations, pro or anti?

The free Voxengo you linked to is very good - I use it myself.

[Ty Ford]

Well I don't know where my reply earlier today went, but it went something like this.

Doug the OP was asking about Mid/Side. He said he was recording trains at some distance. Perhaps an interview.

Then the thread went sideways. Doug, you're not doing this "audio trainspotting" professionally right now so go for it. Do remember that any time you want to increase the width of the sound in post, you'll be turning up two Side tracks and that will result in more noise.

As a result of this thread I reached out to Neumann this morning and have heard back that there are only 14 RSM 191 stereo shotgun mics left and they aren't planning to make any more. here's my review of it from 1990.

Neumann RSM 191 High-end Stereo Shotgun Mic

Ty Ford
Baltimore, MD

Recording in the field is always a challenge. You hope to come back with the good stuff. The stuff you go out with normally determines how good the stuff is that you bring back. In this case, the good stuff is the Neumann RSM 191 stereo/shotgun ($4,550 for mic, power supply, road case and cables). The gig was to record "Larksong", a madrigal group, in several churches and in a recording studio. Getting six members of a madrigal group together is a logistical feat within itself, so I also looked for other opportunities to find the "boundaries" of the mic.

The RSM 191 is two mics in one; a stereo mic and a mono shotgun mic. There are three capsules mounted within an inch of each other; a small-diaphragm front-directed cardioid capsule with a short interference tube and two small side-directed cardioid capsules. A multi-pin cable connects the mic to the MTX191A power supply/pattern box. The MTX191A is a sophisticated and powerful part of the system. Two rotary switches on the front allow for the selection of -M/S, M/S, -X/Y and X/Y operation. When in the M/S modes, the second rotary switch adjusts the Side gain across a range of -9dB to +6dB. When in X/Y modes, the second switch adjusts the width of the pattern for 60 degrees to 170 degrees. Other details include a battery test/battery on switch and a small door which covers the receptacle for a standard 9 VDC battery. The RSM 191 will run on battery or from Phantom Power. On the back of the box are the multi-pin jack for the mic cable, a 5-pin XLR for the output, a 10dB pad and a switch offering two bass roll-offs. A Y-cable attaches to the 5-pin XLR, splitting the side and front capsules.

I had recorded "Larksong" before, using a beyer MC833 stereo mic and a pair of Audio Technica 4050s in Blumlein array. All the early recordings were done in churches. One of the RSM 191 sessions was recorded in one of the same churches we had recorded in before. In all cases, I used GML mic preamps and recorded directly to a Panasonic SV-3900 DAT. While the early recordings were always technically very good, the RSM 191 brought something to the table that the others didn't. I would describe this a coloration or a finish. Normally I steer clear of coloration as much as possible, but this was different. Except for minor pan adjustments, the RSM 191 sessions sounded more like a finished production when I played them back over the studio monitors.

Our best venue was St. John's Church in Ellicott City, MD. We set up in the empty church with the singers standing on parquet flooring in the chancery, facing out to the pews. Choosing the X/Y pattern, I adjusted the MTX191A to get the right angle based on the distance of 8-10 feet from the group. The distance was determined by the tempo of the song and the natural reverberation of the room. I moved back a bit on slower pieces to let more room in and moved up on quicker pieces to keep the room from muddying the phrasing. Decisions were made using an old pair of AKG 240 headphones; designed before they put in a big low-end hump.

In the past, I had pretty much let the singers arrange themselves in an arc, in whatever order they were comfortable with. There was a member change since those sessions and it seemed to throw the balance off. I ended up putting the two most powerful voices -- a soprano and baritone/bass -- at the ends, and moving the others around a bit until the voices started to gel. In further experiments, I moved the singers with the most prominent parts of a song to more centered positions. Finally, for "The Little Drummer Boy", I moved the men and their forceful "rum, rum, rum" behind the women, who were singing the lyric. In all cases, the "finished" quality of the recordings was apparent.

Next was a stop at Flite 3 in Baltimore. As expected, the singers didn't enjoy the experience of singing in an acoustically-damped room. We tried a pair of KM 86s and U 89s in X/Y and coincident omni, but found the RSM 191 to be more open on the top. In a return visit to Flite 3, engineers Louis Mills and Mark Patey and I found the stereo spread of the RSM191 to work extremely well in the studio as a single-source mic for stereo drama. Set at 170 degrees, the stereo image was extremely smooth and stable. In one test, two of us walked around in the studio while a third in the control room, with closed eyes, listened to the control room monitors and pointed out our positions with a great degree of accuracy. In another test, we crumpled up a plastic bag and tossed it across the room. The crinkle made by the bag in flight as it expanded was captured in remarkable detail. After adjusting distances from the mic for individual voice power, we were able to record a very acceptable stereo commercial voice track.

In Studio B, Flite 3 has a Yamaha grand piano. On this particular occasion, I used Great River mic pres and an API lunchbox.With the top open "full stick", I positioned The RSM 191 about three inches inside the piano case, in the middle of the curve and over the longest spoke of the metal frame. I angled the mic slightly to the left, so that the stereo spread would cover both ends of the keyboard. The Great Rivers yielded a very natural, full sound. The API preamps were edgier. Next I tried micing a Martin D28S. Placing the RSM 191 about a foot to two feet out and shooting it right into the sound hole resulted in a large natural sounding acoustic guitar sound that filled the stereo spectrum without being so wide as to be fakey or contrived. It should also be noted that, through all of the stereo applications, there were no mono compatibility problems.

SHOTGUN
For shotgun operation, you just use the front-mounted cardioid capsule. That capsule is related to Neumann's KMR 81 shotgun. It has a 4dB peak at 8kHz that starts at 3.5kHz and returns to zero at 12kHz. The RSM 191 has about the same output as a Sennheiser 416. The capsule in a 416 is in the middle of the tube. In the RSM 191, it's at the bottom of the tube. If you're close-working the mic, that can make a difference. The 416 self noise was more noticeable partly because it was higher in frequency than that of the RSM 191. The actual level of self noise of the RSM 191 was slightly less. The RSM 191 was more natural sounding, with not as much low end sensitivity and not the upper midrange peak of the 416. The 416 had a tighter pattern and more reach.

IN CONCLUSION
I keep coming back to the "finished" sound of the RSM 191. It's not so apparent when listening to a single voice or simple instrument, but when listening to a group of voices or a more complex instrument such as a piano, the resulting sound is very musical. Although that 4dB rise at 8kHz might suggest some undue brightness, I never heard any while using the Great River or GML mic pres. If you're tired of fussing around with a pair of mics for stereo field or studio recording, you owe it to yourself to hear the RSM 191.

Ty Ford can be reached at http://www.tyford.com.
Technique, Inc. © Copyright 1990 All Rights Reserved

[Gary Nattrass]

Originally Posted by John Willett

When I started recording with MS I was certainly not a "full audio engineer" - I was a lad recording for a hobby in my spare time and learned by experimentation and reading magazines. I had no training at all.

As a novice, I found it very easy to pick up.

Are videographers really so stupid that anything slightly technical stumps them completely?

I think not - I certainly hope not - otherwise they would never be able to operate the camera, which is a lot more complicated than simple MS recording.

It may be easy to me and you but I have met many pro cameramen who know very little about audio and just struggle to learn anything about it and these forums are full of similar people, we used to call them the camera luvvies at several ITV companies or even daleks as they had to be told what to do all the time! ;0)

[Paul R Johnson]

I'm afraid that very few active video people are technical to any depth. It's just not considered important nowadays. There's no reason to understand electronics, electrics or optics. Years ago you needed trig to calculate field of view, decent maths to produce resonant circuits (1/2piflc, or something like that from memory), but now, even a basic understanding of physics isn't required, expected, or often important. However, forums like this and others then have to unravel it all!

M/S is quite a difficult concept to pick up for many people, we're talking about how getting it wrong can stress the broadcast chain, and yet we don't explain why it's happening.

People really do not need to be technical any longer (although many, me included. still think it vital) - and the real question is if video production is an art or a craft.

[Seth Bloombaum]

I've got to imagine there are regional differences on this; over here in the upper left corner of the U.S.A. most shooters are quite technical in their understanding of electronics, optics and light, not to mention camera operation.

Deep audio understanding is not as broadspread, and this is an area of gradual change as budget for dedicated soundies on small shoots has continued to shrink. But there is a lot of cross-operation going on, in our community the walls between the disciplines aren't very high or solid.

I'd never say that videographers around here are not "technical" in their understanding of gear.

[Mark Fry]

Originally Posted by Ty Ford

...As a result of this thread I reached out to Neumann this morning and have heard back that there are only 14 RSM 191 stereo shotgun mics left and they aren't planning to make any more. here's my review of it from 1990...

Fascinating. Out of my league, I fear. Looking at UK prices, it's more than my Canon camera, Rode mic, and Vinten tripod cost combined! I suspect that, without similar quality componants throughout the recording and post-production chain, a mic like the Neumann must show up the weaknesses of the rest of the set-up; a bit like running a superbly detailed fine-scale model locomotive on a Hornby train set?

[John Willett]

Originally Posted by Ty Ford

As a result of this thread I reached out to Neumann this morning and have heard back that there are only 14 RSM 191 stereo shotgun mics left and they aren't planning to make any more.

The RSM 191 was an excellent mic., but was expensive and did not sell very many in recent years.

It was more cost-effective to get a mid mic. of your choice and clip a fig-8 to it (the Ambient EMESSER being the most cost-effective).

Also, with many now recording 5.0 sales of the Soundfield were going up and the RSM 191 going down.

Neumann also discontinued the excellent GFM 132 boundary mics.

[Ty Ford]

Originally Posted by Mark Fry

Fascinating. Out of my league, I fear. Looking at UK prices, it's more than my Canon camera, Rode mic, and Vinten tripod cost combined! I suspect that, without similar quality componants throughout the recording and post-production chain, a mic like the Neumann must show up the weaknesses of the rest of the set-up; a bit like running a superbly detailed fine-scale model locomotive on a Hornby train set?

Mark,

As you may be able to tell by my review, I was quite taken with it. Unlike an analog Nagra reel to reel deck which is a handsome antique, it's still viable and capable of recording with great detail, in mono or stereo.

Yes, mankind has left it behind. I hear the more recent sales were to facilities in South America. What do they know or have that we don't? :)

Regards,

Ty Ford