Is the Audio+ 4 channel?

I am looking to build a crossover (and possibly airplay 2 streamer) for my system. Could I achieve that with just the audio+?

The idea is to play audio to the Pi using airplay 2 and use CamillaDSP to route the high pass signal to my amplifier powering my speakers and low pass signal to my subwoofer.

Do I need the 8xOut instead? Is it a doable project? Any help would be appreciated.