Copy and paste into your browser. This is the less expensive unit. The ones we use at work cost about $250.00. I’m not saying the cops we’re using these mics, but I am saying the technology is definitely available and would explain why we didn’t hear background noise.
Also one of the protestors they featured was also speaking on the radio in which there was no background sound at all.
The filtering takes place on the receiving end for certain devices...ie electronic earmuffs.
Police handhelds, the mic and speaker are in one unit. Take a look at the next cop you see and they have a cord from their radio to the mic/speaker that is clipped to their shoulder or chest. It’s all in one.
Two different things.
Go to a gun range and use ‘noise canceling’ earmuffs. You can have a perfectly clear conversation, hear everything, hear the beep of the timer, once the gun goes off the electronics cancels out the noise.
It’s not possible to have that on a handheld radio with the mic/speaker hanging off your body somewhere.