Description
Earthworks M50 (same as M550) 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 M50 requires a standard 48V
phantom power supply. It features an extended
linear free-field frequency response from 3Hz to
50kHz (please see the enclosed individual
calibration chart), very low handling noise,
uniform polar pattern, and 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 M50 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 M50 is ideally suited for
acoustical measurements that require extended
frequency response, including high-end
loudspeaker design and quality control, scientific
research, measurements of ultrasonic or
subsonic transducers, or any application where
an extremely accurate free-field measurement
microphone is required. The very wide linear
minimum-phase response and exceptionally fast
well-damped impulse response (Fig. 2) make the
M50 the perfect microphone for high resolution
time domain measurements.
The M50 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 M50 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: 3Hz to 50kHz +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
(50ea. pin 2 & 3)
Minimum Load: 600btw. pins 2 & 3
Noise: 22dB, A equivalent
Dimensions L x D 229 x 22 mm
(9 x .860 in.)
Weight: 225g (.5lb)
Compliant
Specifications are subject to change without
notice.
Fig. 1. XLR Output Connector Assignment of M50
Fig. 2. Impulse Response (Typical) of M50
Fig. 3. Polar Response (Typical) of M50, 1dB/div.
