Earthworks M23 User manual

Technical Support
Should you have any questions regarding your
M23 microphone please contact us:
e-mail: [e-mail]
phone: [phone] (9a.m. – 5p.m. ET)
For warranty and product return/exchange
information please refer to the back of the
enclosed Calibration Chart.
Earthworks, Inc.
37 Wilton Rd.
Milford, NH 03055 USA
Phone: [phone]
Fax: [phone]
www.EarthworksAudio.com
Made in U.S.A.
M23 Measurement Microphone
Owner’s Manual

Description
Earthworks M23 is an omnidirectional
(pressure) microphone designed and calibrated
for measurement purposes. It is a prepolarized
condenser microphone directly coupled to a
wideband, low output impedance preamplifier.
The M23 requires a standard 48V phantom
power supply. It features a linear free-field
frequency response from 9Hz to 23kHz (please
see the enclosed individual calibration chart),
very low handling noise, uniform polar pattern,
and very high SPL handling capabilities. Its
unique circuitry excludes the transconductance
of the input FET from the overall gain
structure. This means the sensitivity remains
very stable when the microphone is subjected to
variations in ambient temperature. The M23
meets or exceeds ANSI Type 1 requirements.
Each microphone is delivered with its own
calibration chart providing its individually
measured open-circuit sensitivity and the
frequency response curve. A computer file
containing the frequency response data for
importing directly into measurement software is
available from Earthworks, Inc. upon request at
an extra cost. A mounting clip and a calibrator
adapter are included with the microphone.
Applications
Earthworks M23 is ideally suited for
acoustical measurements sound system setup
and troubleshooting, room acoustics, or any
application where an accurate free-field
measurement microphone is required. The wide
linear minimum-phase response and fast well-
damped impulse response (Fig. 2) make the
M23 an excellent microphone for room
acoustics measurements, especially for time
domain measurements.
The M23 is simple to operate. Connect the
microphone to a microphone preamplifier
supplying 48V phantom power using a standard
XLR microphone cable. Please allow up to one
minute for the microphone to settle. Plugging in the
microphone “hot” (phantom power already
present at the input) will not damage the
microphone, and is actually preferred for faster
settling. For optimum results we recommend
pointing the M23 toward the sound source.
This microphone has no removable parts.
Calibration
The microphone is calibrated at the factory
at 1 kHz (therefore independent of any
frequency weighting). The sensitivity in mV/Pa
is provided on the calibration chart. If on-site
calibration is required, use the enclosed ½”
adapter.
Specifications
Frequency response: 9Hz to 23kHz +1/-3dB
Polar Pattern: Omnidirectional
Sensitivity: 30mV/Pa (Typical)
Power Requirements: 48V Phantom, 10mA
Peak Acoustic Input: 142dB SPL
Output: XLR (Fig. 1)
Output Impedance: 100, balanced
(50ea. pin 2 & 3)
Minimum Load: 600btw. pins 2 & 3
Noise: 22dB, A equivalent
Dimensions L x D 229 x 22 mm
(9 x .860 in.)
Weight: 160g (.3lb)
Compliant
Specifications are subject to change without
notice.
Fig. 1. XLR Output Connector Assignment of M23
Fig. 2. Impulse Response (Typical) of M23
Fig. 3. Polar Response (Typical) of M23, 1dB/div.