Gate and Expander
To help eliminating unwanted low level noise (air-conditioning, hum, noise), a Jünger Expander or Gate can be used.
The Jünger Expander attenuates the level of the incoming signal below a certain threshold. Maximum attenuation can be limited by a range parameter. Alternatively switching the system to Gate mode will bring down the levels to full reduction (mute).
Jünger features two different Expander processors.
The newer design is even more flexible, although both systems produce very natural results without disturbing artifacts. In the older design, downward expansion is increased over a level range of 6 dB.
All signals below this range are attenuated by the range value. With the newer design, attenuation is applied using a configurable ratio.
Pictures: Jünger’s Expander/Gate (classic and new design)