DSP Stereo on McIntosh MX120

I play music and cd’s on my MX120.  I have music coming from an airport express into a digital optical in.  The CD player is connected to a coax in.  My subwooer is connected to Zone A coax output.  I have the music setting on DSP Stereo.  In DSP Stereo mode, is the subwoofer used?

Thanks in advance.