Audio-Technica condenser boundary microphones User Manual

AT845R/RW

Frequency in Hertz

Response in dB

10 dB

20k

10k

500

200100

LEGEND

12" or more on axis

Omnidirectional

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, professional 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 balanced 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 is required. To mount these microphones

without

the isolators, a 13⁄16" diameter hole

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 environment, 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.

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 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 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 opencircuit 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

AT847R Frequency Response

10 dB

LEGEND

500

200100

Frequency in Hertz

12" or more on axis

10k

20k

AT847R/RW

Cardioid

Condenser Boundary Microphones

Response in dB

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).

100 Hz

1 kHz 5 kHz 8 kHz

LEGEND

SCALE IS 5 DECIBELS PER DIVISION

120

150

210

240

270

300

330

180

AT845R/RW AT847R/RW

AT845R, AT847R Specifications

Element Fixed-charge back plate

†

permanently polarized condenser

Polar Pattern AT845R Omnidirectional

AT847R Unidirectional (Cardioid in hemisphere

above mounting surface)

Frequency Response 30-20,000 Hz Open Circuit Sensitivity –42 dB (7.9 mV) re 1V at 1 Pa* Impedance 200 ohms Maximum Input Sound Level 142 dB SPL, 1 kHz at 1% T.H.D. Dynamic Range (Typical)

AT845R 112 dB, 1 kHz at Max SPL AT847R 113 dB, 1 kHz at Max SPL

Signal-to-noise Ratio

AT845R 64 dB, 1 kHz at 1 Pa* AT847R 65 dB, 1 kHz at 1 Pa*

Phantom Power Requirements 9-52V DC, 2 mA typical Weight AT845R 2.1 oz (60 grams)

AT847R 2.2 oz (62 grams)

Dimensions AT845R 1.10" (28.0 mm) dia, 2.72" (69.0 mm) length

AT847R 1.18" (30.0 mm) dia, 2.72" (69.0 mm) length

Output Connector Integral 3-pin XLRM-type Accessory Furnished One pair isolators

†In the interest of standards development, A.T.U.S. offers

full details on its test methods to other industry professionals on request.

* 1 Pascal = 10 dynes/cm2 = 10 microbars = 94 dB SPL

Typical, A-weighted, using Audio Precision System One.

270

LEGEND

AT845R Polar Pattern

330

300

240

210

SCALE IS 5 DECIBELS PER DIVISION

1 kHz 5 kHz 8 kHz

AT847R Polar Pattern

120

150

180

AT845R Dimensions

0.79"

20.0 mm

NUT

2.72"

69.0 mm

1.10"

0.33"

8.5 mm

Audio-Technica microphones and accessories purchased in the U.S.A. are warranted for one year from date of purchase by Audio-Technica U.S., Inc. (A.T.U.S.) to be free of defects in materials and workmanship. In event of such defect, product will be repaired promptly without charge or, at our option, replaced with a new product of equal or superior value if delivered to A.T.U.S. or an Authorized Service Center, prepaid, together with the sales slip or other proof of purchase date. excludes defects due to normal wear, abuse, shipping damage, or failure to use product in accordance with instructions. This warranty is void in the event of unauthorized repair or modification.

For return approval and shipping information,

1221 Commerce Drive, Stow, Ohio 44224. Except to the extent precluded by applicable state law,

incidental, or special damages; any warranty of merchantability or fitness for particular purpose expires when this warranty expires.

This warranty gives you specific legal rights, and you may have other rights which vary from state to state.

Outside the U.S.A., please contact your local dealer for warranty details.

Audio-Technica U.S., Inc., 1221 Commerce Drive, Stow, Ohio 44224

28.0 mm

Audio-Technica Limited, Old Lane, Leeds LS11 8AG England

ISOLATORS

CEILING

One-Year Limited Warranty

Prior approval from A.T.U.S. is required for return.

contact the Service Department, Audio-Technica U.S., Inc.,

A.T.U.S. will have no liability for any consequential,

AT847R Dimensions

1.18"

30.0 mm

TABLE

ISOLATORS

26.0 mm

20.0 mm

1.02"

0.79"

LOGO DESIGNATES

FRONT OF MIC

0.33"

8.5 mm

2.72"

69.0 mm

NUT

This warranty

Form No. 0309-9200-02-B/W P50880