What happens to the audio of a reconstructed signal if we remove too much frequency?
Theoretically, the error between the original and the reconstructed signal goes up.  Practically, for actual audio, if you're lowpass filtering too much, the audio starts to sound muffled or muddy -- like you're trying to listen to the event through a pillow.
Again in theory, if you've got a bandlimited signal mixed with noise, the best processing for that signal is to low-pass filter it more than the signal is already bandlimited.  There's a lot of theory out there on how to design optimal filters for this.