Power for your passive sub
Yes, you can fit a subwoofer in a wall, just like a full-range speaker. But it's tough to find room in the wall for powerful amplification to drive that sub. For that, you need a dedicated subwoofer amp like the Monitor Audio IWA-250. It was designed for use with their IWS-10 passive in-wall subwoofer, and can drive it to deliver powerfully pleasing bass. The IWA-250 can even drive two of these in-wall subs, offering 250 watts of power when driving both loads. That's the kind of sub output made for large home theaters that need a second sub for impactful low-frequency effects that are well-balanced throughout the room.
Connections for receivers and integrated amps
If you're using the IWA-250 with a home theater receiver, there are balanced and unbalanced LFE inputs. If you're connecting it to an integrated amp without a subwoofer output, there are stereo RCA inputs with a variable crossover for fine-tuning the low-pass filter. The Class D amp is equipped with digital signal processing to ensure you get even response from your subs at various listening levels while also limiting distortion at high volumes.
Turns on automatically
The IWA-250 has a 12-volt trigger connection, so it can automatically switch on with your receiver, amp, or external control system. It can also be set to power on when an input signal is detected.