My BBK audio system's bass started to sound strange

[shashank22a]

[video="https://www.youtube.com/watch?v=fnH42K5SZC4"][/video]It was all working fine, but since the last week my audio system started to make strange bass sounds

 

[shashank22a]

MERGED QUESTION
Question from shashank22a : "My BBK audio system makes strange bass sounds, please help i don't know what to do."

About a week ago my audio system makes strange bass sounds. It's something is broken? i don't know exactly. I've attached a video[video="https://www.youtube.com/watch?v=fnH42K5SZC4"][/video]