Fig. 6.
Frequency response curves of the 43AE fitted with a low-leak pinna simulator re. 1 kHz.
Frequency Response of the 43AE
For measurement purposes, the 43AE is a simulation of an ear drum, ear canal and pinna
4
.
The diaphragm of the built-in microphone simulates the ear drum and occupies the position
known as the DRP
5
. The simulated ear canal is the hole through which sound reaches the micro-
phone
(see Fig. 2)
. The ERP
6
lies at the entrance of the outer ear. It is also used as the listening
point for the handset of a telephone
(see Fig. 7 and Fig. 8).
Fig. 5.6 shows the frequency response of an IEC 60711 Ear Simulator Type 43AE fitted with a
Low-leak Pinna Simulator RA0056 for both open and closed-ear conditions. At any given fre-
quency f, the corresponding difference
∆
f
between the sound levels at the ERP and DRP is given
as follows:
∆
f
=
DRP
L,f
–
ERP
L,f
In certain cases, for example when testing telephones, ERP
L,f
could be of interest since it repre-
sents the signal originating from the ear piece of a telephone, whereas the microphone buried in
the ear simulator is exposed to, and measures, DRP
L,f
.
4
The part of the outer ear that projects from the head
5
(ear)Drum Reference Point
6
Ear Reference Point
10
LI0070 – 28 June 2017
