Audioscan Axiom - Manual (Page 67)

Axiom ® User's Guide Version 1.8  May 2015
7. Insert the foam tip into the ear, being careful not to advance the probe tube further into the ear canal.
Insertion depth should be as used with insert phones. Allow the foam tip to fully expand in the ear.
8. Click on to generate the real-ear response curve (pink) and the RECD curve (cyan). If the RECD curve
is negative and unstable in the low frequencies, check the seal of the foam tip. Increase the tip size and/or
apply a lubricant to the foam tip to improve the seal.
If the RECD curve deviates more than 10 dB from
the average in the 4 - 6 kHz region, check for proper probe placement and possible blockage of the tube
by the foam tip or cerumen.
9. When these curves are stable, click on to save them.
For comparison purposes, the DSL 5.0 age-related average RECD is shown as a dotted curve on the screen. You
may change this by clicking the Age list button on the RECD setup poster (step 2 above) and selecting a
different age from the drop-down list.
RECD results
The RECD measurement screen shows the response of the RECD transducer in the real ear (pink) and in the 2cc
coupler (green). The difference between these curves is the RECD (cyan). The DSL 5.0 age-appropriate average
RECD is shown for reference (dotted). If the RECD curve deviates more than 10 dB from the average in the 4 -
6 kHz region, check for proper probe placement and possible blockage of the tube by the foam tip or cerumen.
See RECD facts, RECD coupler response, RECD on-ear response.
ANSI S3.46(2013) RECD
The ANSI S3.46(2013) Real Ear standard advises RECD measurement protocols that make the RECD a property
of the ear itself, and independent of transducer or acoustic coupling. To achieve this accuracy certain conditions
must be met in both RECD measurement and Test-box Speechmap coupling.
As earmold tubing effects are dependent on coupled sound source, the ANSI protocol accounts for these by
making the earmold part of the Speechmap testing in the test box. BTE hearing aids are coupled to the HA-1
coupler through the client’s personal earmold.
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