This chart describes the differences between the 2003 and 2009 versions of the ANSI S3.22 hearing aid standard. Please also see our ANSI 96 – ANSI 03 comparison.
2003 |
2009 |
| AGC aids should have their compression set to have minimum effect for all tests except for i/o and attack & release measurements. For those tests, the compression should be set to have maximum effect. | Tests for AGC aids are not required in the standard in 2009. Suggested AGC aid tests are moved to the annex. |
| No definitions for compression or expansion of hearing aids. | New definitions for compression and expansion as used in hearing aids, including the definitions of ratios. |
| All tests assume the use of pure tone test signals. | A new requirement clause was added that in addition to pure tones, also allows the use of a noise signal for response tests if the it results in a gain response that tracks within 1 dB of the response obtained with the use of a pure tone within the pass band of the hearing aid. The FONIX composite signal is such a noise test signal. |
| Response tests are always measured in SPL with pure tone signals. | When using pure tones, the measurement of a response can be in either SPL or gain. When using a noise signal, gain must be used. |
| Input SPL is defined for pure tone test signal. | Input SPL for a pure tone signal is the same as before. Input SPL for a noise signal is limited to the bandwidth of from 200 to 5000 Hz. |
| Resolution of pure tone measurement specified. | Analysis resolution of both pure tone and noise signals is specified. |
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Highlights:
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