Problem with audio [URGENT]!

Hello i'm italian so sorry for my english. i have two computer, one where teams works fine, perfect audio in and out BUT without a webcam , i tried two webcam on my pc but the pc didn't read them.. so i try to use a portable pc that has an integrated webcam. I'have to do exams for university so it's important the webcam. The problem is, that on my portable pc when i'm in a videocall with only one person the audio is good In and out.. BUT, in the previus videoconference in other exams, i heard the voices of all other students and professor very very bad (like robotic vibrating voice) , i'had to say to the professor to write in chat what he said. They hear my voice very well, the problem is the audio out..

I'don't know what to do, it's not a problem of connection because i tried the portable pc on the same room where the other one is, next to the modem.

I'saw a strange thing, when i select for two seconds the audio of the pc and switch to high or lower level.. in the istant that i change the audio of the voices of others is good, then after 2 seconds..the audio returns to be very disturbing and bad..

What i have to do? the exam is the 23 of this month.