Surround Microphones: More Mobile, More Capable
The difference between now and a year ago in 5.1 surround sound can be simply stated: more. As it becomes the norm for more and more sports broadcasts, the transducers that capture that sound will have to be more mobile and more capable. That’s just what this year’s class of surround microphones is doing.
The compact 5100 Mobile Surround microphone, a self-contained plug-and-play solution for 5.1 audio capture, uses five miniature pressure transducers that exhibit extremely low sensitivity to wind and mechanical noise, low distortion, highly consistent low-frequency response, and large dynamic range. Appropriate channel separation and directionality are achieved through a combination of DPA’s proprietary DiPMic (Directional Pressure Microphone) technology, which mounts interference tubes on the L-C-R omni capsules, and the use of acoustic baffles that further preserve the accuracy of levels between the discrete analog output channels.
The 5100’s three front microphones are time-coincident to eliminate comb filtering and ensure frequency consistency when downmixing to stereo or mono. The rear microphones, which feature standard omnidirectional patterns, are optimally spaced both from each other and from the front array to simulate the most natural time-arrival differences.
The low-frequency–effects channel is derived from a summing of the left and right inputs, then attenuated 10 dB as compared with the signal level of the overall L-C-R channels, in accordance with 5.1 surround standards. The 5100 can be mounted on a camera or microphone stand and requires no external signal processing.
The H2-PRO takes surround microphones to the 7.1 plateau (left, center, right, left surround, right surround, center rear, and top). The system is compatible with all eight-channel mic preamps, location recorders, and recording consoles providing phantom power, as well as with all surround-sound encoding/playback formats.
The multidirectional H2-PRO terminates in eight XLR microphone cable-ends that correlate to the standard 5.1 channels and add a top channel for such formats as IMAX and a center-rear channel for extended surround formats, such as Dolby EX and DTS ES. Total harmonic distortion (THD) is less than 1% up to 142-dB sound-pressure level before clipping. Maximum SPL peak before clipping is 142 dB.
The WMS-5 Double M-S (Mid-Side) 5.0 surround microphone is a five-channel microphone in one body that uses double–M-S technology and can be mounted on the camera, boom pole, or pistol grip. The WMS-5 delivers reliable, phase-coherent five-channel sound with five discrete output signals. The M capsule is used for both center with shotgun directivity and front left and right; the S signal, for both front left and right and rear left surround, right surround. The rear M capsule is used for left surround and right surround. All capsules are aligned vertically on the same axis for precise phase coherence. The lightweight (8.3-oz.) and compact (9.25-in.) microphone has a frequency response of 50 Hz to 20 kHz and can handle SPL up to 120 dB.
The DSF-2 Broadcast Microphone System has been specifically developed to simultaneously provide both surround and stereo soundscape at large-scale outside-broadcast events. The multichannel audio it generates from a single-point source is completely phase-coherent, enabling the broadcaster to collapse the surround to stereo or mono for TV and radio feeds without loss of information, frequency imbalance, or any phase problems.
All processing is in the digital domain, and the 1U controller is equipped with digital 750-ohm AES-3id outputs on BNC connectors capable of driving up to 1,000 meters of coaxial cable (subject to correct cable specification).
The DSF-2 outputs stereo left/right (digital and analog), stereo M-S (digital only), and four channels of digital-only SoundField B-Format (W, X, Y, and Z). It is designed to function as either a variable-pattern single (mono) microphone or a variable-pattern, variable-width, coincident stereo microphone array or to generate full surround from the four B-Format outputs, which will then be decoded into 5.1 by the SP451 Surround Processor or Surround Zone software.
This is achieved using four sub-cardioid capsules set in a regular tetrahedron, and adding or subtracting the outputs from these four capsules in different proportions makes it possible to derive all possible polar patterns from omni through cardioids to figure-of-eights. A single multiway cable is used to connect the microphone to the DSF-2 controller that carries both the individual capsule signals and power to the microphone. All microphone parameters can be remotely adjusted from the DSF-2 controller’s front panel.
The SPS422B applies the SoundField concept to stereo, mid-side, and surround applications. In its most basic form, it is a mono and variable-angle stereo microphone with remotely variable pickup patterns, plus the option to deliver mid-side and B-Format outputs.
The SPS422B system consists of two parts used together: a SoundField microphone and an AC-powered 1U SoundField processor. The microphone contains four capsules, mounted in a tetrahedral array (tetrahedral describes an equilateral triangle). This capsule array, combined with its dedicated 1U processor, allows the SPS422B to become a conventional mono omni, cardioid, hyper-cardioid, figure eight, or anything in between. It can be a stereo variable-angle omni, stereo cardioid, or stereo figure eight. It can also be a complete mid-side system for those with sum/difference matrix decoders.
The portable ST350 offers SoundField’s technology in a miniaturized package comprising a lightweight microphone and fully featured compact mic-preamp/control unit that generates surround and stereo simultaneously on balanced-line-level outputs. The microphone electronics are capable of driving long cable runs, enabling the microphone to be positioned hundreds of yards away or alternatively handheld on a short boom close to its control unit. The ST350 features highly matched (between channels) low-noise/distortion mic-preamps with discretely switched gain steps and simultaneous stereo and surround-sound (B-Format) balanced-line-level outputs.