JM27 Description
The JM27 is a microphone in the tradition of classic studio micro-
phones. It is a medium sized diaphragm true capacitor microphone
with a Cardioid head. This feeds the FET type pre amplifier for low
noise. The output balancing is handled by a quality audio output trans-
former.
The capacitor element is manufactured to the classic ‘concentric elec-
trode’ design which provides smooth extended frequency response.
Quality is further enhanced by using dynamic feedback actually at the
capacitor element. This original technique eliminates distortions which
can occur when using this type of microphone for high volume levels.
The capacitor membrane is micro fine Mylar with gold sputtering, volt-
age polarized by phantom power. The microphone body is made of
machined brass; Connection is via screened balanced audio cable
with 3 pin XLR connectors.
Care of Your JM27
Although the ‘Mylar’ membrane on the capacitor is more robust than
the gold foil used by the German originals of the 1930s, it is still ex-
tremely fine and liable to damage if mishandled. There are two safety
factors that MUST be remembered when handling these.
1) Keep the microphone dry.
2) Avoid wind or air blasts directly onto the capsule.
NEVER blow at the capsule. This is the most important single rule for
capacitor microphones. Damage caused by blasts of air on the capsule
are often permanent and require the complete replacement of the ca-
pacitor element (microphone head).
So, never use the microphone in the open air without substantial wind
protection. Use of a pop shield in windy environments is essential. With
instrument recording in the studio though, unprotected use will give the
best sound.
All electronic equipment should be kept dry, but it is even more impor-
tant to avoid any damp conditions when using high quality capacitor
microphones. Damp can cause partial short circuits in the polarizing
voltage, and this will cause crackling noises and low output.
Operation
The JM27 is capable of handling very high sound volume levels so it
can be used safely close to musical instrument amplifiers. Often the
best sounding instrument are close miced, so it is good to take advan-
tage of the JM27’s high dynamic capability in these situations. It is also
a very low noise microphone and suitable for low level or distant miced
instrument recording to the highest quality.
For voice recording, avoid singing directly into the capsule unless an
efficient pop shield is used.
Problems
Should the microphone accidentally become damp and fail to operate
properly (start crackling, or go very quiet) then place it in a warm and
very dry environment for 24 hours. The ideal environment is an airing
cupboard, or under a 100 watt light bulb for a couple of hours.
The JM27 is extremely resistant to physical damage. but if the mi-
crophone fails to work after being dropped, it should be returned in
adequate packing to the supplier. A double test and inspection system
means that manufacturing faults are almost unknown but should any
fault occur, it will be repaired (or replaced) free of charge excepting
where the fault has been caused by physical damage.
Connecting Up
Using a high quality balanced and screened audio cable connect the
microphone head to the microphone amplifier input and switch on the
48V phantom power. NOTE: the microphone will not operate unless
48V phantom power is provided. A few seconds is often needed for the
microphone to reach optimal performance, but be sure to have all audio
levels off for the fist 30 seconds during power up.
Warranty
The JM27 is warranted from defects for a period of 1 year, parts and
labor. Register for your warranty at www.joemeek.com.
Using the JM27
The JM27 gives a very true sound, meaning that the quality of a
recording will depend on microphone placement, and of course, the
performer and the surroundings. The response of the microphone
is CARDIOID; this means that it is much more sensitive to sounds
from the front than from the rear. It is important to remember this
when micing up instruments that project sound from different parts;
i.e. drums, piano, reed instruments etc. The mic placement will affect
the sound quite a bit, so do plenty of experimenting before a take.
Remember that different areas of an instrument often produce very
different sounds, instrument micing is a highly Creative business and
a good technique can make all the difference to the final mix. Once
again, do plenty of takes, and don’t be afraid to experiment. The
JM27 is an extremely capable recording tool: used properly, profes-
sional results will be achieved.
Pre amplification is also important to improve the microphone’s
sounds. Quality systems like the new Joemeek TwinQ can optimize
the JM27’s performance.
Specification
Dimensions
137X22mm
Frequency Response
30Hz-20KHz
Sensitivity
10mV/Pa-40+/-2dB
(0dB= 1 V/Pa 1000Hz)
Polar pattern
Cardioid Diversity> 12dB
(300-3000Hz)
b Diversity> 15dB(1000Hz)
Impedance
200 ohms
Equivalent noise level
18dB (A Weighted)
Max SPL for
130dB
O.5% THD@1OOOHz
Weight
135g
jm27 manual 2.indd
12/9/03, 2:53 PM
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