4
Clamps and stands
When holding a microphone in place, it is important to minimize the influence of the stand on the sound
being measured. This can be accomplished by using low profile stands and clamps available from PCB.
Cables and Electronics
PCB carries LEMO
cables as well as coaxial cables with BNC and 10-32 connectors. Traditional exter-
nally polarized microphone power supplies along with a variety of ICP
®
signal conditioners are available
that will fit almost any need.
6.0
Maintenance
Microphones are very stable over long periods of time, provided they are handled and stored properly.
The microphone contains fragile components that can be damaged by misuse, in particular the diaphragm,
which is made up of a very thin proprietary material and should be kept clean of dust, dirt, moisture and
free any type of imperfection (scratch, dent, etc.).
The microphone’s grid cap is designed to let the true sound pressure level through to the diaphragm while
preventing items from coming in contact with it. We do not recommend that you ever remove the grid cap
or clean the microphone. If you take the precautionary measures to keep the microphone clean and dry, it
should not be necessary. Use of accessories, like windscreens, and desiccants will help keep moisture off
the microphone and maintain the specified sensitivity level. Nose cones will help keep turbulence off the
microphone diaphragm and allow the sound pressure to be measured with greater accuracy.
Keep the microphone and preamplifier assembled while preparing for testing. Keep the rubber mainte-
nance caps on the preamplifier’s electrical connector only. Do not place these rubber caps over the micro-
phone. This will create a vacuum and undo pressure on the microphone diaphragm, which can stretch the
diaphragm and cause a change in sensitivity. Store the microphones and preamplifiers in their protective
cases when not in use. With proper maintenance, the microphone and preamplifier should provide stable
and accurate results for years to come.
Dust, rain, oil, moisture or exposure to extreme temperatures may adversely affect the microphone and
preamplifier’s performance. If the microphone or the inside of the connection area of the preamplifier be-
comes contaminated, use a light pressure rubber bulb to gently blow clean, dry air onto the unit in order to
remove the dust. In the event that you absolutely must take off the grid cap and clean the microphone dia-
phragm, we recommend using a blow bulb or a light pressure, clean and dry air hose to gently blow con-
tamination off the diaphragm. The direction of the air should be parallel with the diaphragm, not directly
(0 degree incidence) pointed at the diaphragm. Do not touch the microphone’s diaphragm with your fin-
gers or let it come in contact with any sharp or pointed object. Please note that any contact to the micro-
phone’s diaphragm can negatively impact the sensitivity and long term stability of the microphone.
If the microphone is ever dropped or comes into contact with any contamination, or is exposed to extreme
temperatures, we recommend immediate recalibration of the microphone. Please note that heat from your
hands can affect the calibration results. It is always good practice to wait a minimum of 30 seconds after
placing the microphone on a test system before taking a calibration reading in order to minimize the effect
that heat from your hands has on the calibration.
7.0
Calibration
PCB offers recalibration services for our precision microphones, as well as units produced by other A2LA
manufacturers. Our internal metrology laboratory is certified to ISO 9001, accredited by A2LA to AN-
SI/IEC 17025 and ANSI/NCSL Z540-1, complies with ISO 10012-1 (and former MIL-STD-45662A), and
uses equipment directly traceable to one or more of the following National Labs (NIST, PTB or DFM).
Our investment in equipment, traceability and conformance to industry standards ensures accurate calibra-
tion against relevant specifications. We also carry a line of acoustic calibrators that can be used to cali-
brate microphone sensitivity on site as needed.
Summary of Contents for HT426E01
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