MBHO MBNM-622 Stereo PZM Microphone

The MBNM-622, a futuristic looking microphone from German manufacturer MBHO, is designed to mimic the way the human auditory system works. I recently took the MBNM-622 for a spin in the recording studio, using it to record a number of different sources in stereo.

The MBNM-622 ($545) features dual pressure zone microphones (PZM) separated by a modified Jecklin Disk baffle. The two omnidirectional condenser PZMs are mounted on an 12-inch diameter base. A felt pad covers the back of the base to prevent slippage and reduce vibrations. Holes are drilled in the base for secure or permanent mounting.

The Jecklin Disk design, pioneered by Juerg Jecklin, simulates human hearing response by spacing two omnidirectional microphones about 6 inches apart, separated by a foam-covered disc. Like our ears, this configuration uses the difference in arrival time (delay), frequency response (spectral energy) and intensity (or level) between the two microphones to provide directional information. Like most other stereo miking setups, directionality is decreased in the lower frequency range (i.e. below 250 Hz).

I first set the MBNM-622 on the wooden floor in the big room at Avalon Sound Studios, outside of Washington D.C. I was preparing to cut some drum tracks for a rock ballad. Since I wanted that ponderous, down the hall, Bonham-ish drum sound, this would be a good chance to check out the 622's stereo ambient abilities.

I set the drums up in the adjacent medium-sized drum room. The kit was close miked with an EV RE20 on the kick, a Shure SM57 and SM81 on the top and bottom of the snare, and a pair of Sony C37Ps in an XY configuration for the cymbals and overall kit. The drum room isolation door was propped open, allowing the drum sound to escape into the main room, where the MBHO stereo PZM was patiently waiting.

After setting levels and monitor balance for the close mics, I brought the PZM faders up, fed through API microphone preamps. And there it was - the classic big (and PZM-boxy) room sound. The delay between direct and room was a bit much, but I easily shifted the tracks to an appropriate timing in Pro Tools later.

After some externally triggered expansion (using the close kick and snare) and some limiting, the stereo room tracks slammed. The expander allowed the room tracks to be wide open on the kick and snare hits without getting too roomy in between.

I also used the MBNM-622 on the studio's 30-year-old Yamaha C3 grand piano - a beautiful instrument. Since this was a rock-ballad, I wanted a brighter, defined piano sound, but it also needed to fit in with the ambient drum sound as well. I decided to use a pair of AKG 451s in an XY configuration over the hammers, slightly favoring the higher strings (gotta leave room for the bass guitar in the mix!).

For the ambient piano sound, I used the 622 taped to the wide-open piano lid. After making a few positional adjustments for phase coherency, the sound came alive. For rock music, I usually use a pair of AKG 451s or 414s without any other microphones. I was happily surprised with the "third dimension" the 622, when fed in at approximately one third of the close microphone's level, added to the piano sound.

I have owned a few PZM microphones over the years, and never got all that comfortable with using them regularly. I would occasionally throw one in the piano and close the lid, but usually for isolation purposes rather than artistic choice. I have achieved good results using PZMs as overall ambient microphones on a choir or horn section, but usually I opted for something more familiar.

The MBNM-622, while still exhibiting some of the "boxy" EQ characteristics of other PZMs I have used, made me re-evaluate my position - especially when I heard its complement to the piano I have recorded so many times.

The ease of set-up, placement and use, coupled with the spacious stereo (and mono compatible) spread, make the MBNM-622 a good addition your microphone list - I just added another brush to my palette.