I want to say "You are just a speaker in a conference room" meaning that you get reduced to a tiny loudspeaker on a conference room full of people where you are actually connected to via teleconference. The main idea I want to convey is that you, to all practical effects, effectively are that tiny loudspeaker people hear you through and that the people in the room just forget about you as a person.
I can see how the original phrase can be interpreted correctly as "You are a person talking in a conference room".
Finally, even with other expressions like "You get reduced to a speaker in a conference room" the same problem appears even if maybe less pronounced.
So, can we do something to make evident I'm talking about speaker (thing) and not speaker (person)? I think that the conference room part helps with the confusion...