Release Time Hearing Aid Test Sequence
This sequence follows the ANSI S3.22-1996 standard method for testing the release time of AGC (automatic gain control) hearing aids.
This sequence follows the ANSI S3.22-1996 standard method for testing the release time of AGC (automatic gain control) hearing aids. A 2 kHz sine tone is played at 90 dBSPL for 1 second and then immediately drops to 55 dBSPL for 2 more seconds. A band limited time envelope (1.5-2.5 kHz) is created and then run through a post processing step, which calculates the release time. It does this by calculating the time it takes the device to stabilize within 4 dB of its steady level.
A limit step is in place to check the release time value, but the exact numbers need to be altered in accordance with the manufacturer’s spec and the tolerances in the standard. For more information, see section 6.15.2 of the standard.
- 2008 – Attack and Release module
- Audio Interface – Listen AudioConnect or similar
- Power Amp – Listen SCAmp or similar
- DC Power Source – Listen DCConnect or similar
- Anechoic Test Box – Bruel & Kjaer 4232 or similar
- 2 cc Coupler – Bruel & Kjaer 4946 or similar
- ½” Reference Mic – B&K 4192 or similar
Hardware Setup and Calibration
- Calibrate the anechoic test box speaker as instructed in the SoundCheck manual.
- Calibrate the reference microphone in the coupler as instructed in the SoundCheck manual.
- Connect the output 1 of your audio interface to the input of the amplifier powering the anechoic test box.
- Position your device inside the coupler, and place them at the reference point inside the anechoic test box. Connect the coupler to your microphone power supply.
- Connect the output of the mic supply to input 1 your audio interface.
This sequence is included in the Sequences folder of your SoundCheck installation.