Audio-Technica condenser boundary microphones instruction

Description

The AT845R is a wide-range condenser microphone with an omnidirectional polar pattern. It is designed for unobtrusive table, ceiling or panel-mounted applications for high-quality sound reinforcement, teleconferencing, profes- sional recording, television and other demanding sound pickup applications.

The AT847R is a similar microphone, with a unidirectional polar pattern. Positioning a properly designed miniature unidirectional microphone centrally on a large, flat, unobstructed surface yields several distinct advantages. The directivity factor is greatly increased over a comparable omnidirectional microphone, thus promoting enhanced gain before feedback and further suppressing ambient noise. Sensitivity is increased for improved signal-to-noise ratio. Phase distortion due to reflected sound energy from the boundary itself is eliminated.

Both microphones require 9V to 52V DC phantom power for operation. The microphones are enclosed in a heavy-duty die-cast case and protected by two layers of heavy perforated steel. The low-profile housing has a low-reflectance black finish. The microphones are also available in white, as AT845RW and AT847RW. Isolators are included with each microphone for applications where mechanical isolation from the mounting surface is required.

Installation and Operation

Output is low impedance balanced. The bal- anced signal appears across Pins 2 and 3, while the ground (shield) connection is Pin 1. Output is phased so that positive acoustic pressure produces positive voltage at Pin 2 in accordance with industry convention.

To mount these microphones in a ceiling or table top without the isolators, a 13⁄16" diameter hole is required. To mount these microphones with the isolators, a 15⁄16" hole is required. The isolators can be placed on either side of the hole for mechanical isolation from the mounting surface.

The Audio-Technica round mark () on the AT847 bezel indicates the “front” of the microphone.

While a modern fixed-charge condenser microphone is not unduly sensitive to the environ- ment, temperature extremes can be harmful. Exposure to high temperature can result in gradual and permanent reduction of the output level. Avoid leaving the microphone in the open sun or in areas where temperatures exceed 110° F (43° C) for long periods of time. Extremely high humidity should also be avoided.

Architects and Engineers Specifications

AT845R [AT845RW]

The microphone shall be a fixed-charge condenser with an omnidirectional polar pattern designed for use in table, ceiling or panel-mount applications. The frequency response shall be

30 Hz to 20,000 Hz. The microphone shall operate from an external 9V to 52V phantom power source. Nominal open-circuit voltage shall be 7.9 mV at

1 kHz, 1 Pascal. Output shall be low impedance balanced (200 ohms).

The microphone shall have a self-contained power module with an XLRM-type output connector.

The microphone shall have a diameter of 1.10" (28.0 mm) and a length of 2.72" (69.0 mm). Weight shall be 2.1 oz (60 grams). The micro- phone shall be housed in a die-cast case with a two-layer perforated steel grille. Finish shall be low-reflectance black [white].

The Audio-Technica AT845R [AT845RW] is specified.

AT847R [AT847RW]

The microphone shall be a fixed-charge condenser with a unidirectional polar pattern designed for use in table-mount applications. The frequency response shall be 30 Hz to 20,000 Hz. The microphone shall operate from an external

9V to 52V phantom power source. Nominal open- circuit output voltage shall be 7.9 mV at 1 kHz,

1 Pascal. Output shall be low impedance balanced (200 ohms).

The microphone shall have a self-contained power module with an XLRM-type output connector.

The microphone shall have a maximum diameter of 1.18" (30.0 mm) and a length of 2.72" (69.0 mm). Weight shall be 2.2 oz (62 grams).The microphone shall be housed in a die-cast case with a two-layer perforated steel grille. Finish shall be low-reflectance black [white].

The Audio-Technica AT847R [AT847RW] is specified.

AT845R Frequency Response
									in dB
								10 dB	Response
50	100	200	500	1k	2k	5k	10k	20k
			Frequency in Hertz

LEGEND		12" or more on axis

	AT847R Frequency Response
									in dB
								10 dB	Response
								10 dB
50	100	200	500	1k	2k	5k	10k	20k
			Frequency in Hertz

LEGEND

12" or more on axis

AT845R/RW

Omnidirectional

AT847R/RW

Cardioid

Audio-Technica condenser boundary microphones specifications AT845R/RW, AT847R/RW