Crackling/Hissing/In a tunnel when voice recording in 2.3.0 [SOLVED]

Hi Folks. Forgive me if this has been answered elsewhere, but I have searched and read for several hours without luck. I am using the latest Audacity version 2.3.0 on an HP Elite Notebook to try and make voice demos via a USB M-Audio Fast Track Interface with a mic. When I try to add a stereo voice track to a song I get the hissing crackling and echoing interference that seems a common problem with hopefully a simple fix. It has worked in the past with the same backing music. Please tell me what setting to check to fix it. Thank you very much.

SOLVED - it was someone’s darn mobile phone left on the stand. This might want to be in the faq. Thanks all