This article applies to the Meeting Owl Pro and Meeting Owl.
There is no mechanism for the Owl to dynamically adjust the Owl speaker volume. The speaker plays whatever the other end sends it.
If the speaker volume lowers when there is background noise in the room with the Owl, what could be happening is the remote end is receiving the background noise, going into half duplex (allowing the transmission of signals in both directions, but not simultaneously), and reducing the volume of its microphone output.
Try having the remote participant put on headphones during your call.