Keep It in the Stereo RealmA GUIDE TO PROFESSIONAL 2-CHANNEL MICROPHONES
Known for their ease of use, precision, versatility and ability to quickly deliver high-quality results, dedicated stereo microphones are sometimes preferable to stereo pairs in recording and live sound applications. Stereo mics provide a point-and-shoot option that is well-suited for many common stereo-miking applications, such as capturing vocals, instruments (including entire drum kits) and live ensembles of varying sizes and configurations. Another advantage of using a single-body stereo mic is consistency, simplifying repeatable setups night after night on the road, or during subsequent studio or location recordings.
Offered by a number of manufacturers in a wide variety of designs and price ranges, professional stereo mics range from sophisticated, high-end models to versions suited for any budget. What's more, manufacturers create products that are optimized to handle one or more specific stereo-miking techniques: coincident schemes such as Blumlein, X/Y and mid-side (M-S; see sidebar on page 32 for more information about M-S miking); near-coincident techniques such as the ORTF (Office de Radiodiffusion Télévision Française) array; and the binaural approach, modeled on human hearing and involving the use of a dummy head with capsules implanted in its “ears.”
This article surveys currently available stereo mic models and covers only single-body, dual-capsule designs for the studio. It excludes stereo shotguns, surround mics, multichannel mic arrays and stereo mic “kits” that combine two mics into a stereo package. All of the products mentioned offer balanced outputs with XLR connectors (5-pin or dual 3-pin); unbalanced models with ¼- or ⅛-inch jacks were excluded.
The Audio Engineering Associates (AEA) R88 ($1,895, www.wesdooley.com) stereo ribbon mic for Blumlein or M-S stereo recording measures 14 inches long and 2.5 inches in diameter, and weighs 3 pounds (less cable). It incorporates the RCA 44's Large Ribbon Geometry configuration for a 20Hz bass response and a smooth high end for capturing complex tones. It houses a matched pair of figure-8 mics with 2-inch ribbon motors that are oriented at 90 degrees for superior off-axis rejection. The R88 offers a frequency response of 20 to 15k Hz, -52dBV/Pa sensitivity and handles 165dB SPL @ 1 kHz.
Audio-Technica's AT825 ($549, www.audio-technica.com) accommodates X/Y recording. It comprises two matched, fixed-charge, back-plate condenser elements that are configured side-by-side in a fixed 110-degree angle. The AT825's response is 30 to 20k Hz, with a switchable LF roll-off of 150 Hz (at 6dB/octave). Its signal-to-noise ratio measures 70 dB (1 kHz @ 1 Pa), and it handles 126dB SPL at 1k-ohm (at 1-percent THD). The mic operates on either battery or phantom power, and includes a 16.5-foot shielded cable with a 5-pin XLR at the mic end and two standard 3-pin XLR-M output connectors.
Designed for X/Y recording, Beyerdynamic's MCE 72 ($489, www.beyerdynamic.com) has two cardioid pattern electret condenser capsules mounted ±60 degrees relative to its axis. The MCE 72 uses 5-pin XLR connections, and is powered by a standard 1.5-volt battery with an LED power indicator. Its response is 60 to 20k Hz, and max SPL at 1 kHz is 123 dB. Also for X/Y recording, the MCE 82 ($839) has two cardioid condenser capsules mounted ±45 degrees relative to its axis. Response is 50 to 20k Hz, and max SPL at 1 kHz is 128 dB. The MCE 82's elastic suspension system suppresses handling and cable noise, and it offers a switchable bass filter. It can be operated with any 12 to 48VDC phantom power or 1.5V battery, and includes an LED battery-power indicator. The MC 833 ($3,699) supports M-S, X/Y and mono recording without an additional matrix. It is equipped with three externally polarized cardioid condenser elements. The middle element supplies the mono signal in M-S applications. The condenser elements to the left and right are used for X/Y recording or can be combined to form a figure-8 polar pattern to supply the side signal. The three capsules can be mechanically adjusted and continuously varied over a wide range.
The two Pressure Zone Microphones (PZMs) in Crown's SASS-P MK II ($1,830, www.crownaudio.com) are aligned in a mono-compatible, near-coincident array, mounted on boundaries with a foam barrier between them to facilitate directional pickup and limit overlap of the two sides at higher frequencies. The polar patterns are omnidirectional at low frequencies and unidirectional at high frequencies. The SASS-P MK II has a 20 to 18k Hz response; signal-to-noise ratio is 73.5 dB @ 94dB SPL. It offers 6mV/Pa sensitivity and handles 150dB SPL @ 3-percent THD. It can be powered by two 9V batteries or 12 to 48VDC phantom. The SASS-P MK II includes a foam-lined carrying case, hand grip, mic stand adapter and windscreen.
The striking design of MBHO's MBNM 622 E PZ ($545, www.mbho.de) combines a Jecklin Disc — a circular, rubber foam-covered barrier mount for absorbing sound that measures 6×12 inches (H×D) — with two omnidirectional boundary-layer mics mounted on each side of the bisected disc and spaced about 6.5 inches apart. The MBNM 622 offers a hemispherical polar pattern and a frequency response of 10 to 26k Hz (±1.5 dB); sensitivity is rated at 5 mV/Pa @ 1 kHz, and max SPL is 130 dB.
Intended for X/Y and M-S applications, the Neumann USM 69 i ($3,699, www.neumannusa.com) features two separate gold-sputtered, dual-diaphragm capsules that rotate over a 270-degree range. Color markings on the lower-capsule system indicate the angle relative to the upper capsule. Five selectable polar patterns — omni, cardioid, figure-8, hypercardioid and wide-cardioid — are available for each capsule, and the outputs of the two channels can be linked (cascaded) to yield other characteristics. Both mic amplifiers feature high-output capability and low self-noise. The USM 69 i is available in black or nickel finishes, and is sold with IC 6 cable (swivel mount to 5-pin XLR) and AC 20 cable that splits the 5-pin XLR to dual 3-pin XLR outputs.
Neumann's KU 100 ($4,999) binaural stereo microphone is a replica of the human head with microphone capsules built into the ears. The KU 100 uses transformerless circuitry for achieving high-output capability, fast transient response and low self-noise. Inside the head are switches for -10dB attenuation and the highpass filter (for linear, 40Hz or 150Hz settings). The underside of the unit has balanced (XLR) and unbalanced (BNC) outputs, and a switch for selecting power supply modes. The KU 100 can be operated with 48V phantom power from the provided external AC power supply unit or from its built-in battery. The KU 100 comes in a robust aluminum carrying case that includes a 5-pin XLR cable and the AC-20 adapter cable.
Pearl's TL4 ($2,267) and TL44 ($2,513; dist. by Independent Audio, www.independentaudio.com) both combine the company's classic rectangular, dual-membrane capsules mounted back-to-back in a compact black-chrome body. Each offers cardioid, figure-8, omni and 180-degree coincident stereo polar patterns. Both models have 5-pin XLR outputs, weigh 9.1 ounces and use quiet, transformerless preamplifier circuits. Response of both mics is 20 to 20k Hz, with 126dB SPL handling. The TL4's sensitivity is rated at 120 mV/Pa; the TL44's is 16 mV/Pa.
Pearl's DS60 ($6,241) model supports X/Y, M-S and Blumlein techniques. Its brass body is finished in black chromium and gold-plated mesh, and it has two rectangular dual-membrane capsules mounted one above the other at 90 degrees apart. Each capsule offers a selection of cardioid, figure-8 and omnidirectional patterns. The DS60's response is 18 to 25k Hz. Its preamplifier has four output channels — one for each cardioid membrane — that are connected via a 9-pin Lemo plug and a four-way splitter terminating in 3-pin XLRs. Its sensitivity is rated at 16 mV/Pa with self-noise at 15 dBA.
The RØDE NT4 ($899, www.rodemic.com) is housed in a heavy-duty, cast-metal body with a satin-nickel finish. Its two half-inch cardioid capsules with gold-sputtered diaphragms offer X/Y miking fixed at a 90-degree angle. The NT4 has a self-noise of 16 dBA and handles 143dB SPLs. Stated response is 20 to 20k Hz, and the mic offers selectable 9V battery or phantom power operation at 12, 24 or 48V and includes an LED power indicator. The NT4 includes a custom carry case, windshield, XLR-to-mini-jack adapter and dual XLR cables.
Offered in matte-black chrome and satin-nickel finishes, Royer Labs' SF-12 ($2,150, www.royerlabs.com) is housed in an ingot iron case that forms part of the magnetic return circuit. Its two matched 1.8-micron, aluminum-ribbon, figure-8 transducers are placed one above the other, each aimed 45 degrees off-axis from center in the Blumlein configuration. Both capsules can provide mono recording, and two channels can be combined for mono recording without creating phase artifacts. The SF-12's response is 30 to 15k Hz (±3 dB), and it handles SPL levels up to 130 dB. The SF-12's extension cable comes with a “Y” adapter that splits into two 3-pin male XLR outputs.
Royer's SF-24 ($3,800) stereo ribbon mic is optimized for Blumlein and M-S configurations, and comes in an optical black finish; 18-karat gold is optional. It shares the SF-12's design characteristics while adding Royer's active electronics system, allowing the SF-24 to be used with any preamplifier with average gain characteristics. The SF-24 operates on 48V phantom power and contains two fully balanced, discrete head amplifier systems using specially wound toroidal transformers. Stated response is 40 to 15k Hz (±2 dB), and max SPL handling is 130 dB. The SF-24's output of -38 dB is 14 dB more sensitive than the non-powered SF-12. Custom-designed FETs provide quiet operation, with self-noise less than 18 dB. The SF-24's output connector is a 5-pin male XLR.
Sanken's ($2,295, www.sanken-mic.com) CUW-180 handles both stereo and surround applications. Its two cardioid condenser microphones are oriented at 180 degrees and are independently adjustable with a 15-degree detent for X/Y configurations. The precise alignment of both capsules is said to maintain optimum on-axis response and phase coherence. The CUW-180 has a 5-pin XLR output.
In Schoeps' CMXY 4Vg ($4,295, www.schoeps.de), the angle between the axes of the two built-in cardioid CCM 4V condenser capsules (with lateral pickup patterns) can be adjusted continuously between 0 and 180 degrees without affecting the main stereo axis for precise imaging in an X/Y configuration. The capsules rotate equally and in opposite directions via gear arrangement in the microphone's base. Response is 40 to 20k Hz, with max SPL of 132 dB. The CMXY 4Vg is powered by 12- or 48V phantom power and terminates with a 5-pin XLR-M connector. The package includes Schoeps' AK SU/2U adapter cable (5-pin female XLR to two 3-pin male XLRs).
The spherical design and matte-gray surface finish of Schoeps' KFM 6 ($6,699) resembles a binaural dummy head and follows similar principles. The KFM 6 records at a fixed angle of 90 degrees and is designed to yield a natural impression of space, depth and image. Two pressure transducers are mounted flush on the surface of the 20cm diameter sphere, acting as an acoustic baffle. The KFM 6's directionality is essentially constant throughout the audio frequency range, which is 18 to 16k Hz. The KFM 6's sensitivity is rated at 100 mV/Pa, its signal-to-noise ratio is 77 dBA and it handles 123dB SPL. It accepts 12- or 48V phantom power, ships with a suspension mount, a KG ball-and-socket joint for stand-mounting, a “Y” adapter cable, 5-pin XLR stereo cables and a wooden case.
The Schoeps KFM 360 ($5,550) is an 18cm spherical microphone with two CCM 8L figure-8 capsules that record at an angle of 120 degrees for close-miking applications. It also ships with a “Y” adapter cable and mounting accessories, and can be adapted for surround applications with the company's DSP-4 KFM 360 ($6,305) processor, which has built-in AD/DA converters.
Schoeps' MSTC 64g ($2,879) is designed for near-coincident ORTF miking. It has a T-shaped body with two built-in mic amplifiers and a matched pair of MK 4 cardioid capsules from the company's Colette Modular System, mounted 17 cm apart at an angle of 110 degrees. The MSTC 64g is powered by 12- or 48V phantom power, its frequency range is 40 to 20k Hz, sensitivity is rated at 13 mV/Pa, signal-to-noise ratio is 78 dBA and max SPL handling is 132 dB. The MSTC 64g terminates in a 5-pin XLR male connector.
The Sennheiser MKE 44P ($795, www.sennheiserusa.com) is an electret condenser design with two cardioid capsules set at 90 degrees for X/Y applications. Its spring-mounted capsule is designed to suppress handling noise, and it features a two-position LF roll-off filter. The MKE 44P handles max SPL levels of 126 dB (with THD @ 1 percent). It features a 40 to 20k Hz response, and sensitivity is 6.3 mV/Pa (±2.5 dB). Operation is via 12 to 48V phantom power or 1.5V alkaline battery. Lastly, it has a transformerless output on a 5-pin XLR connector and ships with an adapter cable (comprising one 5-pin female XLR to two 3-pin XLR-M connectors), a velour-foam wind shield and a foam-lined case.
Shure's VP88 ($1,266 list, www.shure.com) M-S stereo mic combines two condenser capsules: a forward-facing cardioid and a bidirectional side element. An internal M-S matrix offers three selectable degrees of stereo image separation. The internal matrix can be bypassed if an external matrix is used or if stereo imaging is handled in post-production. A switchable LF roll-off (12dB/octave at 80 Hz) is standard, and the mic powers from an internal battery or any 9 to 52VDC phantom source. Frequency response is 40 to 20k Hz, and typical self-noise is 24 dBA. The VP88 package includes a “Y” splitter cable, windscreen, 6V battery and zippered storage bag.
Studio Projects' LSD-2 ($1,000, www.studioprojectsusa.com) puts two dual-membrane condenser mics within a single housing, allowing for X/Y, M-S and Blumlein techniques. Its 1.06-inch diameter capsules are mounted in close proximity on a vertical axis; the upper-capsule assembly rotates 270 degrees relative to the lower capsule. A single-layer brass mesh surrounds the capsules. Two three-way switches control polar response, highpass filtering and -10dB pad for each capsule. The LSD-2 ships with a dedicated 7-pin XLR to dual 3-pin XLR cable, windscreen, shockmount and carrying case.
BS-3D Binaural Spheres from T.H.E. ($2,648, www.theaudio.com) are made of wood and come in golden-oak and black-walnut finishes. Each one is individually handcrafted by Bud Poulin. T.H.E. incorporates its patented preamps and matches the two omni capsules for frequency response and output. The BS-3D is designed to produce excellent phase cohesion for a stereo sound that translates to a stereo or mono mix. Each sphere has a 5-pin male XLR connector, and each mic ships with a 6.5-foot cable (custom lengths are available) with a 5-pin XLR on one end and two 3-pin XLRs on the other.
The Telefunken Ela M 270 ($15,995, www.telefunkenusa.com) stereo tube condenser microphone is a limited-edition re-creation of the original Telefunken Ela M 270 designed for X/Y, M-S or Blumlein configurations. The mic features dual 1-inch, gold-sputtered, 6-micron CK12 capsules placed one on top of the other, offering three polar patterns per capsule: cardioid, omni and figure-8. Its frequency range is 20 to 20k Hz. The Ela M 270 is 8.5 inches long and weighs 2 pounds.
Matt Gallagher is an assistant editor at Mix.
REFRESHER: MID-SIDE RECORDING
Of all stereo-miking techniques, mid-side recording is the most versatile, allowing the greatest degree of control over the stereo image during the mix, while providing total mono compatibility. Although the process may seem complicated at first, it's quite simple. M-S recording is a coincident technique involving two microphones: one in a bidirectional pattern and one typically in cardioid, although other patterns can be used. Here, unlike in straightforward left-right stereo recording, the whole of your soundstage is represented by one forward-facing (“mid”) channel and the extreme side information in the other (“side”). The outputs of these two microphones are added and subtracted in a matrix system (M + S+ = Left and M + S- = Right; where S+ is the output of the bidirectional mic and S- is the phase-inverted bidirectional output) to create a stereo image.
To set up an M-S configuration, point your cardioid microphone directly toward the sound source and the bidirectional mic perpendicular (with its diaphragms at 90-degree angles to the source). Place the capsules as close together as possible to align nulls. (Note: Many of the stereo microphones profiled in this article are configurable for M-S.) Record the mid-signal on one channel and side signal to another. Matrixing can be performed via a dedicated decoder unit or manually by routing the mid-output to a single fader, panned to the center; and the side output to two faders, panned hard-left and -right, respectively (with right channel phase-reversed). Sum the mid- and positive side (panned left) to the left bus and the mid- and negative side (panned right) to the right bus; experiment with the width of your stereo image by adjusting mid- and side fader levels, keeping in mind that you can swap your perspective (drummer left/right, for instance) by swapping the phase on the side channels.
Royer SF-24 Stereo Ribbon Mic
Producer/engineer Gary Grant to record trumpeter Malcolm McNab's Exquisite: The [Royer] SF-24 has a tremendously rich, spacious character that provides the fullness of sound I was going after. When we needed a slight bit more articulation, we brought up the level of the other mic, but for the most part it was the SF-24 that really made this recording shine. During all the sessions, the SF-24 effectively served as the Decca Tree. We placed the SF-24 10 feet up in the room and 12 feet back from the primary mic, and it performed flawlessly-with clarity and a beautiful presence.
Florida-based audio engineer Gary Faller had a unique project: to rig a pair of large-diaphragm DPA 4041 stereo mics on the roof of the U.S. Air Force Hangar AE at Cape Canaveral Air Force Station, Fla., to capture the sound of a Delta Rocket as it streaks into space to launch a Global Positioning System (GPS) satellite. MORE
Recording engineer and producer Jim Anderson recently employed the new Sanken CUW-180 stereo microphone for PBS's In Performance at the White House. Anderson, who has won eight Grammy Awards and Latin Grammy Awards with 22 nominations, is the Chair of the Clive Davis Department of Recorded Music at New York University and has been the engineer for the White House series for the past 15 years. MORE
Multiple Grammy Award-winning engineer/producer Al Schmitt to record singer/songwriter Paul Anka's Rock Swings: I used the [Royer] SF-24 for ambience on the saxophone section. The mic was terrific. The SF-24 delivered a really rich sound and was exactly what I was looking for on that particular project.
caption: Arturo Sandoval (left) and Robert Fernandez
Scoring engineer Robert Fernandez on recording trumpeter Arturo Sandoval for My Life in Idlewild film: By including the SF-24, I was able to bring it into the mix as an ambient mic, or I could make the trumpet a bit more present by just pulling the SF-24 back a bit and allowing the R-122 to come forward. This combination gave me exactly what I needed to blend Arturo's performances into the overall ambience of the film. Trumpet is known as a difficult instrument to record because of its characteristically high sound pressure levels," continues Fernandez. "For me, the R-122 is the perfect microphone for recording Arturo because it can withstand the trumpet's level without distorting, and that's what I love about the microphone. With the R-122, I get a very musical recording.
Producer David Chesky's miking style: When I used to conduct for television and movies, I would stand in front of an orchestra and it would sound great. I was a kid then, 19 or 20 years old. They'd have 20, 30 microphones set up and then we'd go back to mix it and it would always sound weird to me because the engineers would essentially be putting the orchestra back together. That stuck with me, and when I started my own label later, I wanted the sound to be from a single point and not all divided to be reassembled later. That's why we started doing M/S recording. The multitrack is cool for certain things, but our philosophy is trying to document the live event and we do it with a stereo microphone. We set the musicians up very carefully and the electronics are minimal, but we're using the best-sounding equipment we can. When you hear our stuff, it's super-clear - everything is the best wire, the best amplifier, the best mic pre.
Avant-garde composer Zeljko McMullen is using Fritz-Neumann's nickname for its KU 100 model human head, which features microphone elements located inside its replica ears-to create several new binaural projects that are sure to offer listeners a new perspective on their music. MORE
Michael Bishop on recording brass and woodwinds: Lately, though, I've been using the Neumann KU 100 binaural head with very good results. In the past, I was never really one to subscribe to binaural recording. I thought it was interesting but never very practical, since most people will be hearing it over loudspeakers, not headphones. But one of the features of the KU 100 is that it's loudspeaker-compatible. The one thing you lose on speakers is the sense of height that the [binaural] head can give you on headphones, and you don't get the behind-you effect. But I use them because the stereo imaging is so good and so accurate, and tonally it works and it can handle the level of a brass quintet.
D5-PBensusan3_sm.jpg: Pierre Bensusan tracking with an SF-24 and two small-diaphragm condensers
Bidirectional Microphone download pdf here
"The Bidirectional Microphone: A Forgotten Patriarch" by Ron Streicher (AES Fellow, Pacific Audio-Visual Enterprises) and Wes Dooley (AES Fellow, AEA), courtesy AEA