Fixing audio, not the simple stuff

Using Ubuntu 18.04 2.2.2 audacity.

I recorded audio from a sound board while I was videoing a performance. The meter on my camera never saturated, but it stayed very constant. The audio that was recorded is very bad. (see sample) Audio analysis is very new to me, but I have done image processing and data analysis so I understand signal processing. If necessary I can write python or octave programs to fix it, But I have no idea what is wrong and how to fix it. It does not help that I am a little deaf.
I have attached a small sample of the audio.
What analysis can I do to find out what is wrong? the spectral analysis does not look like what is think it should, the low freq smooth?

This topic is more about audio processing the simple audio manipulation. I think it has something to do with frequency and harmonics.

I have looked at the waveform at it looks like the signal to me has been clipped. all the waveform are flattened on top.
Now how do I “round” the flat waveform.
In engineering I would pass it through a low pass filter. But now how do I determine the frequency in audacity?

Now I did that but now there is an “echo”

You can make a “slight” improvement by:

  1. Split the track to mono and delete the silent track (https://manual.audacityteam.org/man/splitting_and_joining_stereo_tracks.html)
  2. Apply a low pass filter, with filter frequency around 6000 Hz, 48 dB per octave (https://manual.audacityteam.org/man/low_pass_filter.html)

but you’re right, the recording is trash, so there’s not much you can do with it.