The original “test_before.mp3” sounds perfectly clear to me.
My suggestion would be to add two Nyquist plugins to your copy of Audacity …
Limiter.ny ( to replace the native compressor effect, whose release-time is way too slow IMO )
and DeEsser.ny ( which reduces sibilance which will become more obvious after using a compressor/limiter)
So my suggested chain would be …
HighPassFilter...: rolloff="12 dB" frequency=100.000000
Normalize: ApplyGain=yes RemoveDcOffset=yes Level=-1.000000 StereoIndependent=no
Limiter...: thresh=-10.000000 hold=10.000000 makeup=1
Limiter...: thresh=-5.000000 hold=10.000000 makeup=1
De-Esser: control-action-choice="Apply changes" control-absolute-threshold=-18.000000 control-step-dur-ms=5.000000 control-frequency-bound1=3000.000000 control-frequency-bound2=10000.000000 control-n-bands=5 control-crossfade-interval=5.000000
T-Chain.txt (493 Bytes)
DeClicking could be incorporated into the chain, (another additional plugin), but including that increase the processing-time to a multiple of the playback-time, ( at least 3x).