I'd interpreted that as no visible speakers. It's not uncommon for speakers to be encased in devices with no obvious outlet. But you highlight a good point, although it's misleading, it's not entirely incorrect. It's a summation from a characters point of view, telling you what they see. Or so that's how I took it, as opposed to a narrator telling you the observations in full. But it is misleading for sure.

I also thought that specific description related only to the door and not the device.

Ah yes, it could have been more clear. My thought was that turning back to the doors made the subject the doors exclusively. Good catch, can't edit :() Thanks~