Video Sample Test of the Xiaomi Mi3 Showing Audio problem

This is a sample recording to show the audio quality of mi3 from a video recording. The music sounded muffled and has sudden ups and downs in the clarity of the recording.

The recording was done at night in a room without any background noise other than the music. Volume from speaker was already quite loud. I had adjusted it louder so that the phone could record it better. Phone was held in a landscape position and the sides were not obstructed. Mi3 is on ver 23 Miui.

I have posted problem in xiaomi forum. Waiting for any follow up advise.