Translation: from Tekno Speak to English …American style.
Hard of hearing persons almost always have a diminished dynamic range…meaning they can’t hear soft sounds and loud sounds distort and are uncomfortable.
To handle this problem digital hearing aids compress the loud sounds down to a comfortable level and boost the soft sounds up so they can be heard. This is called non-linear amplification or compression.
All aids amplify the sound to compensate for the diminished sensitivity. Sound is calibrated in decibels (db) which is a measurement of how loud the sound is.
The normal mammalian hearing system (yes you are a mammal) is extremely sensitive to soft sounds but naturally compresses loud sounds. That means that to a normal ear a perceived loudness of twice as loud is in reality 10 times louder.
To hard of hearing 10 times louder is perceived as 10 times louder (not twice as loud like a normal hearing person hears) This condition is called Recruitment.
All aids have a MPO or maximum power output circuit to limit very loud sounds. All MPO’s cause some distortion (lack of clearness) if pushed too far.
Attack and Release times are how fast in milliseconds the compression responds to loud sounds. You see the amplifier in your hearing aid normally amplifies linearly meaning that a 65db sound is amplified by whatever the gain adjustment setting is for that particular tone say 25 db.
So 25 plus 65db means that 90 db’s of sound would be put into your ear. That’s quite loud and might be uncomfortable. So the computer in your aid senses that (knee point) and cuts the amplification down to a comfortable level. But this takes time to detect and operate…that is the Attack time. Now after the loud sounds cease, the amplification is returned to normal…the Release time. Ed