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Allowable A-weighted Room Noise During
Audiometric Testing
The current ANSI Standard "Maximum Permissible Ambient Noise
Levels (MPANLs) For Audiometric Test Rooms"
[ANSI S3.1-1999 (R2013)] includes octave band and one-third octave
band permissible noise levels for both supra-aural and
ER-3 Series insert earphones. See the ER-3C Calibration Manual for more
information.
Room noise below 45 dBA should provide accurate audiometric testing to 0
dB HL. A room noise of 65 dBA should provide accurate screening to 20 dB
HL.
Both of those guidelines depend on use of a foam eartip properly inserted
as described on page 4, which provides an average external noise
exclusion of approximately 40 dB, with a minimum of 36 dB at 2 kHz.
CALIBRATION
•
Before calibration, con rm that the impedance of the earphones matches
the requirements of the audiometric equipment. The labels on the
earphones identify the impedance. Unless the audiometer was purchased
with ER-3C earphones pre-calibrated by the audiometric equipment
manufacturer, the Reference Equivalent Threshold Sound Pressure Levels
(RETSPL) values and procedure cited in the current version of the ANSI
S3.6 or IEC 60645-1 standard must be used to calibrate the equipment prior
to initial use. Re-calibration should subsequently be performed at intervals
speci ed by the audiometric equipment manufacturer, in compliance with
national and international standards and regulations.
•
Correction factors can be applied where it is necessary to alternate
between insert earphones and a supra-aural earphone with audiometers
that do not provide a dual-calibration option.
CARE AND CLEANING
Use a damp cloth to wipe down any parts that become soiled during
normal use.
Antimicrobials (glutaraldehyde) are safe for external surfaces.
Any other agents must be tested before using to prevent damage.
Do not submerge earphones in any liquid or allow liquid into the
Sound delivery tubes.
Do not use alcohol or other strong chemicals or solvents to clean
Earphones or any parts, including cables, sound delivery tubes and
eartips.
ACCESSORIES AND REPLACEMENT PARTS
Accessories and replacement parts are available from Etymotic Research
and its authorized distributors
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