AKG MICROPHONES - Boundary - Wall, floor, ceiling, table, lectern
Intended for applications ranging from providing sound reinforcement of stage performances to courtroom, surveillance and security recordings, this selection of microphones all mount flat on a surface, taking advantage of the clarity and consistency obtained by placing the diaphragm close to the boundary of the acoustic space.
C547 BL - Hyper-cardioid
The C547 BL is a hyper-cardioid, professional, boundary-layer microphone. The 'rugged, non-crush case and a switchable bass-cut filter make the C547 BL an ideal choice for tough on-stage assignments'. Built on the same acoustical components as the C747 V11, the microphone provides 'high directivity and neutral sound'.
Primarily designed for use in houses of worship, theatres and conferencing, the C547 BL is also a 'good choice for miking kick drums and other instruments'. The 'highly efficient' RFi-Shield technology 'substantially reduces interference noise due to electromagnetic pollution'. A typical placement for this microphone would be directly on the floor of stage, near the edge, thus out of sight to the audience. Alternatively it could be placed on a lectern, table or even a TV news desk.
The low profile housing has a grille assembly which may be painted to blend in with stage decoration. A low-cut switch integrated into the XLR connector may be used to reduce disturbing low frequency noise. The integral, captive, cable is 3 metres long and terminated with an XLR connector.
Output connector: 3-pin, male XLR. Applications: Voice, instruments, stage or conference. Response: 30Hz-18kHz. Sensitivity: 8.5mV/Pa. Phantom power: 9-52V DC. Dimensions: 185 x 120 x 20 (l x w x h) mm. Weight: 380g without cable.
Included accessories: W547 foam windshield.
CBL99 - Hemi-spherical
The CBL99 is a 'hemispherical boundary layer microphone designed to deliver superior results for a multitude of recording applications', small, lightweight and easy to place. It is 'extremely small and inconspicuous', has a 'studio-quality microphone capsule', 'high sensitivity and low self-noise'.
The transducer sits in a metal plate only 5mm thick, frequency response is 'very uniform within its hemisphere' (when mounted to a surface of sufficient size), and it 'captures the room sound' of an instrument 'very accurately'.
Note that since this microphone has a hemi-spherical pattern, it receives sound at an equal level from all directions except through the base of the plate. As a result it could be very useful for a round-table discussion, mounted on the underside of a grand-piano lid or mounted on a wall, but in none of those cases if it is feeding a loudspeaker which is within the range of that hemisphere.
The CBL99 requires phantom power. Its output is balanced, via a captive cable terminated with an XLR connector which has an integrated switch for a bass-cut filter. It is a circular, matt black, metal plate with three, countersunk, mounting holes. Three small holes drilled in the centre act as the grille of the transducer.
Output connector: 3-pin, male XLR. Applications: Recording voice or instruments. Response: 20Hz-20kHz. Sensitivity: 20mV/Pa. Phantom power: 9-52V DC. Dimensions: 5 x 80 (h x diameter) mm. Weight: 56g without cable.
C562 CM - Hemi-spherical
A 'professional,flush-mount, boundary microphone', designed for permanent, 'invisible' mounting in ceilings, walls, tables and stages, the C562 CM is characterised by 'excellent clarity and a consistent pickup anywhere around' the microphone, styled by AKG as the 'Invisible ear' for recording, courtroom, surveillance and security applications and a 'perfect tool for surveillance or live recording'.
It has a hemi-spherical polar pattern for 'clear, intelligible pickup of speech'. 'high sensitivity for a great pickup area' and a 'low-profile cylindrical design perfect for wall or tabletop installation'.
Note that since this microphone has a hemi-spherical pattern, it receives sound at an equal level from all directions except through the base of the plate. As a result it could be very useful for a round-table discussion or mounted on a wall, but in neither of these cases if it is feeding a loudspeaker which is within the range of that hemisphere.
The microphone is meant to be mounted through a sheet of material or a plate. A 3mm thick, 20mm diameter, bevelled disc sits on the surface of the plate, showing only four drilled holes in the matt nickel-plated surface.
Behind this, a threaded cylinder fits through a 12.5mm hole in the plate, held in position by a milled nut. The cylinder is 25mm in length, and contains the electret capsule and a cable grip for the captive cable which exits from the cylinder at the rear.
This cable is 500mm long, terminated with a two pole miniature jack plug, which is small enough to go through the mounting hole. The plug mates with a cable socket with 500mm of cable, connected to an extended-length XLR connector containing a phantom power adapter.
Output connector: 3-pin, male XLR. Applications: Recording, courtroom, surveillance and security applications. Response: 20Hz-20kHz. Sensitivity: 25mV/Pa. Phantom power: 9-52V DC. Dimensions: 3 x 20(depth x diameter) mm plate;.25 x 12(depth x diameter) mm rear cylinder. Weight: 30g without cable.
When a microphone diaphragm is placed very close to a flat surface it is said to be in the 'pressure zone' or at the acoustical boundary of the room. This is the region where any reflections of acoustic waves will be so short that they will have a frequency way above the range of human hearing, thus avoiding the comb-filtering, or interference of the direct sound by the reflected sound, experienced when placing a normal microphone near a reflective surface.
Canford is a main dealer for AKG microphones and accessories. If the model desired can not be located on the site, please contact Sales.