I think that the "SOX" is a Linux command and I'm not a Linux gay, For the example you share I got the same result using audacity by applying the noise reduction option as in this tutorial and just using the default values: https://www.youtube.com/watch?v=10FFKl_0GSA From the example you share its look like you need another good mic to avoid that strong voice, I was straggling with my old mic too, now I'm using a good quality mic, getting a good voice recording plus auto noise reduction, meaning the mic record only my voice and not the entourage voices.
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