Attack/Recovery Time - Interacoustics Affinity 2.0 Additional Information

2.0
Affinity Additional Information
3.7.5

Attack/Recovery Time

The Attack time is the time it takes for the hearing aid compressor to react to an increase in input signal. As
the output will gradually move towards the final gain value it has been decided to define the attack time as
the time it takes the hearing aid to stabilize the output within 2 or 3 dB according to the IEC 6018-2 and ANSI
S3.22 respectively. The attack time is commonly 5 ms but can be longer.
The Recovery is the time taken for the hearing aid compressor to react to a decrease in input level. As the
output will gradually move towards the final gain value it has been decided to define the recovery time as the
time it takes the hearing aid to stabilize the output within 2 (following an input decrease from 80 to 55 dB) or
4 dB (following an input decrease from 90 to 55 dB) according to the IEC 118-2 and ANSI S3.22
respectively. The release time is commonly 20 ms but can be longer.
Measuring the attack and recovery time gives you an idea of the time constants within the hearing aid and
how fast it reacts to incoming sounds. If the recovery time is too short the gain will vary too much during
speech that shifts quickly in amplitude, phase and frequency. This will distort the signal. In hearing aids with
short attack time and long recovery time the distortion will be minor. The main disadvantage in this case will
be extremely brief sounds such as a door slamming will cause the gain to decrease as the attack time is
short. However the gain will stay low for a while due to the long recovery time which may result in the client
missing information during this period.
Note: If using the IEC standard the this test should be performed with the volume control in its maximum
position (e.g. before Reference Test Gain)
Below is an example:
Attack
Select test
View specific attack/
recovery information
Recovery
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