The DP-L2 from Toa Electronics is a digital audio processor that automatically adjusts output volume in response to changing ambient noise levels. Typical applications include voice announcement systems for airports, shopping malls and restaurants.

The unit features an automatic level control (ALC) algorithm that adjusts the input signal relative to the surrounding ambient noise level, ensuring an appropriate input signal level at all times. The DP-L2 can distinguish between its own output and the surrounding ambient noise, ensuring more accurate level-setting.

Two balanced line inputs and outputs are provided along with an ambient noise sensor microphone input and a monitor output. A range of microphones may be used for detecting ambient noise, including ceiling mounted, dynamic and condenser types.