
User’s Guide
AECM206 Headphone Test Fixture: User’s Guide 3
Inspection and preparation
Removal from the packaging
See Figure 1. The test fixture is protected for shipment by
contoured foam in a strong carton or hard travel case. The
fixture must be removed with care. For this purpose, a sling
is provided. Pull the sling upwards with one hand while eas-
ing the base of the test fixture out of the case with the other
hand.
Carefully remove the coiled audio cables from their cavity.
Be sure to carefully coil the cables, and to encircle the test
fixture with the sling when replacing it into the foam cutout.
To carry the AECM206, support both the neck and head
simultaneously.
Components
The headphone test fixture consists of a massive tubular
head, fitted on a neck, which is connected to a circular base.
The head encloses an internal cavity where the ear simula-
tor/preamplifier assemblies are mounted. The hat provides a
support for the headband provided with most headphones.
The AECM304 ear simulator is fitted with an internal mea-
surement microphone and is threaded for attachment to the
426M15 preamplifier. Each AECM304/426M15 assembly
is a mated pair, calibrated together. The components must
not be interchanged between assemblies.
At the acoustic end, each AECM304 is fitted with an ear
canal extension. The ear canal extensions project slightly
from the right and left side ends of the head. An alignment
ring plate is mounted on each end, to secure the pinnae and
aid in alignment when mounting headphones. See Figures 2
through 6.
Figure 2. Headphone Test Fixture key components
Face
Alignment
ring plate
Alignment
stud
Hat
Head
Neck
Neck cavity
(located in back)
Base
Collar
Preamplier
cables