Bad sound quality on downloaded recording

@Ivorm 

Since you say that the microphones and speakers are installed separately, we can infer the following.

The microphones and speakers are connected to a mixer amplifier, which in turn is connected to a laptop PC via the mixer amplifier.
In this case, the signal output from the mixer amplifier is at line level (several hundred mV), and the microphone input jack on the laptop corresponds to the microphone level (several mV).
In other words, if the mixer amplifier and laptop are connected directly, the laptop will receive a signal above the allowable level, and the laptop will not be able to process the signal properly.
The sound will be cracked or the microphone will automatically switch to the main unit microphone.
As a countermeasure, it often works well to attenuate the signal from the mixer amplifier to the microphone level before inputting it to the laptop, or to convert it to a USB input using a USB audio conversion adapter.