Thursday, October 31, 2013

Neumann RSM 191 Stereo/Shotgun Mic - Going, Going, Gone!

Neumann RSM191
The Neumann RSM191 is on the endangered species list because the factory only had fourteen of them left a few weeks ago, when I asked. After they are gone, Neumann says they have no plans to make more. The RSM191 will then fade into history as one kick-ass, remote controllable stereo/shotgun microphone. If you want one, it will probably be a special order. Why bother to post this review? It's just a great sounding microphone system.

Neumann MTX191A

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 (10/31/13: Originally $4,550 for mic, MTX191A power supply/remote control, road case and cables, I just saw one for $6000 on Ebay). B&H shows the mic as discontinued, but does list windscreen, foam, cables and mounting accessories. 

Inside the RSM 191 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. (Note: A stereo/shotgun mic works in either of two modes; stereo mic or shotgun mic, but not both at the same time.) 

RSM191 Multipin Mic Connector
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. 

Neumann MTX191A Power Supply/Remote

Other details include a battery test/battery on switch and a small door which covers the receptacle for a standard 9 VDC battery that powers the system when Phantom Power is not available.

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. 

My first 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.

Neumann RSM191 Side Capsule Response
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. 

Neumann RSM191 Mid Capsule Response
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. 

Neumann RSM191 Polar Patterns
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.  

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.  

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. Again, the RSM191 is not long for this world. You may have to make an extra effort to order one of the remaining new ones, but I don't think you'll be disappointed. 

By Neumann's kind permission, here's a 17-page tutorial on Mid/Side recording and the RSM191 written by Neumann's Stephen Peus.

Ty Ford can be reached at
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1 comment:

  1. Thank you for sharing your experiences with the RSM191. You mention yours having less low end response than the Sennheiser 416. I remember in the manual of the RSM191 it is written that there is a wire on the PCB of the mic that can be cut if more bass response is desired. I haven't done so yet, but keep it in mind in case I once need it. Is your wire intact or cut when you compare it to the 416?