Earthworks M30BX User manual

Technical Support
Should you have any questions regarding
yourM30BXmicrophoneplease contact us:
e-mail:Suppor[email protected]
phone: [phone], ext. 119
(9am – 5pm ET)
Forwarrantyandproductreturn/exchange
information please refer to the back of the
enclosed Calibration Chart.
Electronic Calibration Files
All Earthworks Measurement Micro-
phones purchased after July 1, 2012 will
have ECFs available at no charge. Simply
register your new measurement micro-
phone within 30 days of purchase on our
website.
Once your Measurement microphone has
been registered in our database, we will
send you your ECF to the valid email ad-
dress provided in your registration. If you
have any questions you can email us at
[email protected] or reach us
by phone at 603-654-6427 ext. 114.
FIFTEEN-YEAR WARRANTY
All Earthworks products (excluding acces-
sories) carry a fteen-year limited warranty
(parts and labor). If you have any problems
with your Earthworks products, please con-
tact our warranty/repair department by
email at: [email protected]om or
by telephone at [phone], Ext. 119.
Earthworks, Inc.
37 Wilton Rd.
Milford, NH 03055 USA
Phone: [phone]
Fax: [phone]
earthworksaudio.com
Made in U.S.A.
Printed in U.S.A.

Description
Earthworks M30BX is an omnidirectional
(pressure) microphone designed and cali-
brated for measurement purposes. It is a pre-
polarized condenser microphone directly
coupled to a wideband, low output imped-
ance preamplier. The M30BX requires a sin-
gle type P28L (Lithium) or 4LR44 or equiva-
lent 6V battery as a power source. It features
a linear free-eld frequency response from
9 Hz to 30kHz (please see the enclosed indi-
vidual calibration chart).It has very low han-
dling noise, a uniform polar pattern, and has
6dB of extra gain available. Its unique circuit-
ry excludes the transconductance of the in-
put FET from the overall gain structure. This
means the sensitivity remains very stable
when the microphone is subjected to varia-
tions in ambient temperature. The M30BX
meets or exceeds ANSI Type 1 requirements.
Each microphone is delivered with its own
calibrationchartprovidingitsindividuallymea-
suredopen-circuitsensitivityforbothgainposi-
tions,andthefrequencyresponsecurve.Acom-
puter le containing the frequency response
data for importing directly into measurement
softwareisavailablefromEarthworks,Inc.upon
request at an extra cost. A mounting clip, a cali-
brator adapter, an XLR to RCA adapter, and a
battery are included with the microphone.
Applications
Earthworks M30BX is ideally suited for on-
location acoustical measurements including
loudspeaker design and quality control, sound
systemsetupandtroubleshooting,roomacous-
tics, or any application where an accurate free-
eldmeasurementmicrophoneisrequiredand
portability isimportant or apower sourceisnot
readilyavailable.Manytestsystemsmanufactur-
ers, such as DRA Labs (MLSSA™), Smaart™
and DEQX™, are recommending M30BX
microphones.The wide linear minimum-phase
responseandfastwell-dampedimpulseresponse
(Fig. 2) make M30BX an excellent microphone
for loudspeaker design, especially for time do-
main measurements.
The M30BX is simple to operate. Make sure
the battery (included) is properly installed in
the microphone. To open the battery com-
partment hold the microphone by the upper
body and unscrew the lower, larger part of
the microphone (this cover is not remov-
able). The battery is only switched on when
an XLR connector is plugged into the mi-
crophone. The M30BX will not operate from
phantom power.
The M30BX will drive either balanced or
unbalanced inputs. An XLR to RCA adapter is
enclosedfordrivingunbalancedinputsofsound
cardsdirectly.PleasenotethatthebestS/Nratio
is achieved using a balanced interface.
Insidethebatterycompartmentthereisagain
switch. At the“0dB”setting the M30BX has nor-
mal condenser sensitivity. At the “6dB” setting
theextradBofgainisapplied,eliminatinganeed
foranexternalpreamplierformostapplications.
Calibration
The microphone is calibrated at the factory
at 1 kHz (therefore independent of any fre-
quency weighting). The sensitivity in mV/Pa
is provided on the calibration chart for both
gain positions. Make sure to use the actual
data rather than relying upo n the nominal
14dB gain gure. If on-site calibration is re-
quired, use the enclosed one half inch stan-
dard calibration adapter.
Specications
Frequency response: 9Hz to 30kHz +1/-3dB
Polar Pattern: Omnidirectional
Sensitivity: 30mV/Pa (Typical)
with 6dB Gain 60mV/Pa (Typical)
Power Requirements: 6V Battery Type P28
(2CR-1/N,4LR44or eq.)
Peak Acoustic Input: 130dB SPL
with 14dB Gain 124dB SPL
Output: XLR (Fig. 1)
Minimum Load: 600Ωbtw. pins 2 & 3
Noise: 22dB, A equivalent
Dimensions L x D: 220 x23mm
(8.65 x .910 in.)
Weight: 180g (.4lb)
Compliant
Fig 1. XLR Output Connector Assignment of M30BX
Fig 2. Impulse Response (Typical) of M30BX
Fig 3. Polar Response (Typical) of M30BX
Version 5 July 12, 2012 Specications are subject to change without notice.