Speaker only sound not working

Hi All,

I have HP ENVY 17t-3000 CTO 3D Edition Notebook PC. it comes with the integrated Beats Audio. Earlier i had good sound. now sounds only coming through the Speaker  and Headphone.

When i make only speaker as default device sounds cant hear. when i select Speaker an Headphone sound quality very low.

I need to go back to speaker only. Appreciate your support

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Thanks