special purpose average (hearing aid) (SPA)

The test procedures for hearing aids are explained in DINIEC 60118. In addition to the average value for the sound pressure or gain, the High Frequency Average( HFA), there is also the Special Average.

These two values differ in that for the HFA value, the three frequencies are specified in the standard, whereas for the Special Purpose Average ( SPA), they are specified by the manufacturer.

In addition to the characteristic value for the special average, there is also an average value for high frequencies, the High Frequency Average (HFA).