Sucks muffles and three of the speakers do not work

I really like base but while listening on other speakers or headphones, the song gets muffled and the base ruins it

Kebidu 2 in 1 5.1 Channel AC3/DTS 3.5mm Audio Gear Digital Surround Sound Stereo (L/R) Signals Decoder HD Player with USB Port, Black, and the 5.1 surround absolutely works.