Please check sound quality and advise

Adjust the preamp for the highest signal-to-noise***** ratio.
Then use the Audacity tools, (e.g. “RMS Normalize” & limiter), to make the audio comply with ACX specifications.

[ ***** The noise-level on your audio is already good,
the optimum preamp gain setting will be close to what you’ve got it set at now ].

http ://wiki.audacityteam.org/wiki/Nyquist_Analyze_Plug-ins#ACX_Check