I want to use captive audience in my sales copy but even though that phrase is exactly the meaning I am trying to convey, I want to avoid the word captive as it carries a negative connotation. Is there a 2 or 3 word phrase that has the same meaning but has a positive, or at least a neutral connotation?
Captive audience -- M-W
a person or people who are unable to leave a place and are thus forced to listen to what is being said
The passengers on the plane were a captive audience.
This is usually only applicable if your audience is unable to leave, even though they don't want to stay and watch.
But instead, consider captivated (audience) -- Vocabulary
Use the adjective captivated to describe someone who is utterly charmed by something.
A captivated student is enthralled by her teacher's history lesson, and a captivated audience is involved in every word spoken on stage during a play.
Similarly, you can use synonyms of captivated as well. Examples: charmed, delighted, enthralled, entranced, enchanted.