I'll say the oem speakers in Cady's are 1,000,000,00 times better than the stock ones in an Impala SS.
Well, I got a partial permutation of total loss. My RF channel is kapoot. I noticed the tweeter crackling for a month and die, and then the coax got fuzzy and finally croaked. I'm half-tempted to connect something just to see if it's just the speakers. But I admit your having the entire radio die at once is not a good sign.
For the OP, did you try jiggling the wires in the trunk?. Or hitting it? Couldn't hurt.
\'96SS SOB: SSRI, Herter Tune, Tri-Y II, , 3000 Edge, F/HO bars, METCO extendeds with CV MMC, Bilsteins, currently Vredestein Ultrac Sessanta (315/35 rear). Finally, wait for it... LT-4 knock module!
\'96FWB BUW-Butt Ugly White: PCMPerformance tune, HDFA w/ swissed filter, 1/2 SLP s.s. catback with H- and Flow Super 50s, oem opti rebuilt 3 times, SS Bars, METCO LCA, Airlift 1000, Monroe SS, PowerTrax No-Slip, CTS wheels with +1 rubber. Finally, yes again... LT-4 knock module!