How do I fix stereo speakers that suddenly stopped working? on 2006 Lexus LX470

Speakers worked when car was turned off. No sound in any mode when car turned back on. Turned car off again, on again, then speakers worked for a second before quitting. No sound now.

Asked by for the 2006 Lexus LX470
It may be the speakers or the even the stereo. Need to have some one who is skilled determine which one is the culprit.