Etymotic Research ER 3C User Manual

User Guide

TM

INSERT EARPHONES

INTRODUCTION AND INTENDED USE

ER-3C™ earphones are the next generation of insert earphones by
Etymotic Research, designed to replace Etymotic’s ER-3A® Tubephone
earphones, which have been the worldwide standard for audiometric
insert earphones since 1985.

ER-3 Series earphones are intended for use with audiometric
equipment used in hearing testing in audiology clinics, auditory
research and screening in industrial and educational settings.
They are well suited for unfavorable test environments that may
have high ambient noise levels. The frequency response and
performance characteristics of ER-3C earphones are virtually
identical to the original ER3-A earphones at all audiometric
frequencies and approximate those of Telephonics® TDH 39,
49 and 50 supra-aural earphones.

Advantages of ER-3C earphones:

• Incorporates “touch-proof” electrical connection for safety

• Duplicates ER-3A smooth frequency response

• 30+ dB external noise exclusion – equivalent to a single-wall booth
when used with deeply-sealed foam eartips

• 70+ dB isolation (interaural attenuation) between ears;
reduces the need for masking

• Reduces test/retest variability compared to supra-aural earphones

• Eliminates test errors due to collapsed ear canals

• Simplifies RECD (Real-Ear-to-Coupler-Difference) measurements

• May be calibrated in a 2-cc coupler, occluded ear simulator,
or 0.4-cc coupler

SYSTEM INCLUDES

• ER-3C earphones (10 Ohm or 50 Ohm)

• 7' cable with dual-mono 6.33 mm (1/4") plugs

• 20 foam eartips (regular, 13 mm)

• 20 foam eartips (small, 10 mm)

• 2 foam eartips (large, 18 mm)

• Hook-and-loop neckstrap

WARNINGS

• Do not use insert earphones when medically contraindicated,
e.g., draining ear, infection, ear canal laceration or other otologic
condition where use of insert earphones could potentially exacerbate
a medical condition.

• ER-3 Series earphones can produce high sound pressure levels.
Use caution when selecting presentation level and duration.

• Reliable test results can be obtained with ER-3C earphones only
when the audiometric equipment they are used with is calibrated
b

efore initial use and at subsequent intervals as specified
audiometric equipment manufacturer, in compliance with national
and international standards and regulations.

•

ER-3C earphones are available in 10-Ohm and 50-Ohm
It is essential that the correct impedance be used in accordance
with the specifications of the audiometric equipment. Labels on the
earphones identify the earphone impedance.

• Use of accessories or replacement parts other than those supplied
by Etymotic Research or its authorized distributors may result in
inaccurate results.

• Modification or alteration of any parts may invalidate test results.
Example: The sound delivery tube should not be cut. A change of
10 mm in the length of the sound delivery tube will change the
frequency response by 0.5 dB at some frequencies.

• Do not use in or near strong magnetic fields (e.g., MRI).

• Do not reuse eartips. All eartips, regardless of material or construction
are for single-person use only. Replace eartips for each test session.

2 3

EARTIPS

• Foam eartips are recommended for most uses. They are available in
three sizes: standard 8-13 mm (ER3-14A), small 6-9 mm (ER3-14B)
and large 10-14 mm (ER3-14C).

• Infant eartips are available in two sizes: (ER3-14D 3.5 mm and
ER3-14E 4 mm). See page 10.

• Multiple sizes of Single-Use Eartips
commonly used in immittance and otoacoustic emissions testing
can be used with single-use earptip adapters (ER3-06X).
No data are available on the interaural attenuation or noise exclusion
of immittance eartips.

All eartips, regardless of material or construction are for single person

use only. Replace eartips for each test session. Do not reuse eartips.

WARNINGS

• Do not use insert earphones when medically contraindicated,
e.g., draining ear, infection, ear canal laceration or other otologic
condition where use of insert earphones could potentially exacerbate
a medical condition.

• ER-3 Series earphones can produce high sound pressure levels.
Use caution when selecting presentation level and duration.

• Reliable test results can be obtained with ER-3C earphones only
when the audiometric equipment they are used with is calibrated
b

efore initial use and at subsequent intervals as specified

by the
audiometric equipment manufacturer, in compliance with national
and international standards and regulations.

•

ER-3C earphones are available in 10-Ohm and 50-Ohm

impedance.
It is essential that the correct impedance be used in accordance
with the specifications of the audiometric equipment. Labels on the
earphones identify the earphone impedance.

• Use of accessories or replacement parts other than those supplied
by Etymotic Research or its authorized distributors may result in
inaccurate results.

• Modification or alteration of any parts may invalidate test results.
Example: The sound delivery tube should not be cut. A change of
10 mm in the length of the sound delivery tube will change the
frequency response by 0.5 dB at some frequencies.

• Do not use in or near strong magnetic fields (e.g., MRI).

• Do not reuse eartips. All eartips, regardless of material or construction
are for single-person use only. Replace eartips for each test session.

EARTIPS

• Foam eartips are recommended for most uses. They are available in
three sizes: standard 8-13 mm (ER3-14A), small 6-9 mm (ER3-14B)
and large 10-14 mm (ER3-14C).

• Infant eartips are available in two sizes: (ER3-14D 3.5 mm and
ER3-14E 4 mm). See page 10.

• Multiple sizes of Single-Use Eartips™ 3 mm-16 mm (ER10D-T series)
commonly used in immittance and otoacoustic emissions testing
can be used with single-use earptip adapters (ER3-06X).
No data are available on the interaural attenuation or noise exclusion
of immittance eartips.

All eartips, regardless of material or construction are for single person

use only. Replace eartips for each test session. Do not reuse eartips.

EARTIP COUPLING

Foam eartips developed for ER-3C Series insert earphones have
dimensions that ensure proper calibration and test accuracy.

1. The length of black tubing from the end of the sound tube adapter
through the foam eartip is 26 mm. Do not cut the black tubing that
connects the foam eartip to the sound tube.

Notes

• Do not cut the sound delivery tube. A change of 10 mm in the

length of the sound tube will change the frequency response
by 0.5 dB at some frequencies.

• Replace the sound delivery tubes (ER3-21) if they crack or harden.

• When using single-use eartip adapters, calibration will be maintained

if the eartip is seated on the adapter so that the opening of the
eartip is flush with the tip of the adapter.

26 mm

Sound delivery
tube adapter

Sound
delivery
tube

Foam eartip

Black
tubing

2. To obtain the noise exclusion and interaural attenuation shown
on pages 6-7, insertion depth should be 14-15 mm into the
ear canal. This depth is achieved when the outside edge of
the foam eartip is 2-3 mm inside the entrance to the ear canal.

Correct insertion

2-3 mm

Insertion = too shallow

Correct insertion

2-3 mm

7. Insert the eartip into the ear canal.

• The purpose of deeply inserted eartips is to maximize
interaural attenuation and noise exclusion.

• There is usually less than a 3-dB difference in eardrum pressure
between shallow and deeply-sealed eartips. The accuracy of
threshold is less dependent on insertion depth.

8. Correct insertion depth: When the outside edge of the eartip is

2-3 mm inside the entrance of the ear canal.

9. Allow foam to expand to acoustically seal the ear canal.

• Hold/press the eartip in place until it expands.

• If correct insertion depth cannot be achieved, try rolling the foam
into a smaller diameter before insertion. If unsuccessful, use a
different size eartip.

• If the seal is inadequate, try another eartip.

10. Discard eartips after each person use.

6. To facilitate proper placement, firmly roll the foam eartip into the

smallest diameter possible.

adapter

Sound delivery
tube adapter

Sound
delivery
tube

Foam eartip

4 5

INSTRUCTIONS FOR USE

1. Refer to the audiometer manual for instructions on properly

connecting the earphones.

2. Examine the ear canal for obstruction or excessive cerumen.

3. Visually determine for each ear canal if a different size eartip

other than the standard foam eartip is required.

4. Make sure the sound delivery tube is not blocked.

5. Insert the black tubing of an ER3 foam eartip completely onto the

adapter of the sound delivery tube.