Phonak Target 35db soft sounds + threshold knee-point

I believe that instead of compression, something called expansion is applied to soft sounds. Expansion is the opposite of compression.

A compressor with ratio of 2:1 will cut volumes above the threshold level to half. So if the compressor kicks in at 30 dB (threshold level) with a ratio of 2:1, a 40 dB signal would lead to a 35 dB output. This is because the 40 dB signal exceeds the threshold of 30 dB by 10 dB, but the 2:1 compression compresses this 10 dB to 5 dB. So the louder the sound, the more of the gain is cut by the compressor. One way to cause more compression at a certain level is to start compressing earlier (lower threshold), or less compression by starting the compression later.

When the signal is expanded, the most gain is applied to the signal at the threshold and least to the softest signals. Threshold is now the point where the expansion stops, so higher input levels are not expanded. Let’s say we set the expansion threshold to 30 dB and let’s say that a 20 dB signal is expanded to 25 dB. If we want to expand it to 22 dB decibels, one way to do this is to move the threshold higher. If we want a higher output, we move the threshold down.

I think this is essentially what you do with TK/Gain 35dB. If the threshold is set to 35 dB, a 20 dB input signal will get less gain than if the threshold was set to 30 dB. So essentially the lower the threshold, the more gain really soft sounds get. Raising the gain for 35 dB inputs means that also the gain for softer sounds is increased, but they increase more for the 35 dB sounds than softer sounds, effectively making 35 dB sounds stand out better.

In Phonak Target we can’t directly affect the kneepoint, only the G35. However, following the manual as quoted by @Zebras suggests lowering the G35 would increase the kneepoint and thus following @bungybanana effectively amplify the 20dB range more.

This is something we can test, albeit a bit hard, since I for one probably haven’t heard sounds in the 20dB range for years. They are different sounds than we’re used to, not just softer sounds. Probably won’t know what to do with those cues.

We’re having a heat wave in Holland and we are not used to heat waves. (Usually only AC in cars and offices.) So I won’t be testing this until I am not feeling this hot. If someone does: Please post!

What are you trying to achieve if I may ask?