I understood the actual reason behind the disturbance of the audio and its equipment. We can easily improve the defects found in the audio by following the instructions mentioned above by a musician. This article is quite meaningful for the musician coming new to this field and do now know the basics of it.
You should improve your future videos quality. This one is pretty bad. No offense.
The video that you have posted above is a huge help for me! I am not really into these kinds of technical stuffs, but sometimes I can say that I get interested with the magic behind the works of having good audio. I am a music lover myself so I totally understand how important it is to have a good audio for better listening. Anyway, I haven't heard that there is actually a profession that is related with making audios better. I have a friend who loves editing videos and I believe the tips that you have mentioned above will really help him a lot in making his videos better than before. I will let you know my thoughts after trying and applying all the tips that you have given above.
is here on his soap box, so take it with a grain of salt.