yes it can be done. first goto Audio MIDI Setup located in Utilities folder once open click + sign at bottom left and choose Create Multi-Output Device once created it will show in left hand column of Audio Devices Window. click on Multi-Output Device then in the right column you will see device options ie. Studio Display , Built-in Output, etc;....check Studio Display Speakers and Built-In Output ( the boxes will then turn blue ) next you will need a 3.5 to whatever the input may be on the Subwoofer... Cable. in my case for example I needed an 3.5 to RCA...once proper cable is acquired connect said cable 3.5 end to apple headphone jack and then other end to subwoofer...next goto Sound in the Apple desktop menu and choose Multi-Output Device then open your playback software ( I've only tested this using Apple Music / Pine / VLC but all should work) ... fyi if sub sounds out of phase or wonky in some way then engage Drift Correction for Built-in Output ( again found in Audio MIDI setup ) ALSO the volume , and this is important, will now be controlled Directly by the playback software ie. Music / Spotify etc; the attached file shows the Sound Volume control disengaged ...I'm using a M&K VX-7B for sub, mono input , crossed over @ 75 Hz sounds thunderous...running MacOS Ventura 13.0 beta on a 2017 MacBook Pro Thunderbolted to Apple Studio Display
