Sure, simply pretend that PORT is a cassette deck. To some extent you will have dueling Volume controls. You’ll need to work out the details that make the most sense in your environment. You can preset the CVT3030 to a certain Volume level and use a SONOS controller to adjust PORT’s output, you can fix PORT’s output and use the CVT3030’s Volume control, or keep PORT’s output variable and fight it out during each listening session.

Thanks for the super fast and clear reply! I’ll try it.