Syrinscape Online Player on macOS with Rogue Amoeba Loopback

I’m trying to set up audio for a campaign. I’m on macOS Big Sur and want to direct the Syrinscape Online Player audio to Webex Meetings (for reasons). I have also tested with Discord.

I am using Loopback from Rogue Amoeba to create a virtual interface that includes my microphone and various source apps from which I will draw audio. Syrinscape Online Player is the primary audio source besides my microphone for the gaming, but I can add other apps that may play music/sounds, so I do. I set up the Loopback virtual interface as the audio input in Webex Meetings and Discord. This follows the instructions from Rogue Amoeba:

Other apps’ audio shows up on the test meters in Loopback, Webex Meetings, and Discord when I test this virtual interface. My microphone audio shows up on the meters.

Syrinscape Online Player audio does not work. I do not see the meters in Loopback show any audio output from Syrinscape Audio Player. I also do not see any audio output from my virtual interface in Webex Meetings or Discord when I can hear audio playing from my headphones via Syrinscape Online Player.

Because I see no audio activity from Syrinscape Online Player in Loopback’s source list, I’m wondering if there’s actually some sort of subprocess or something that is playing the Syrinscape audio. When I add Syrinscape Online Player to Loopback, I add it from the Running Applications list. Perhaps I need to add Syrinscape to Loopback another way, or add something from its application bundle?