so this has been bugging me for probably three weeks now and im at the point where im just posting here because ive run out of ideas. my 7300 is transmitting fine, reports are good, power output looks normal on the meter, but the received audio has gotten really muddy and kind of muffled sounding. like if someone is on SSB it almost sounds like theyre underwater a bit. CW is fine weirdly enough, like i can copy CW no problem but voice modes are just rough.

i already went through the menu and reset the AF filter settings back to default because i thought maybe i accidentally bumped something. didnt help. tried different headphones and the internal speaker, same thing on both. swapped out the USB cable too just in case something weird was going on there even though i dont think thats related.

the radio is about 4 years old and has never been opened. no physical damage that i know of. just kind of gradually got worse over a few weeks rather than being a sudden thing. anyone dealt with something like this before?

gradual degradation over weeks on the receive audio side, not transmit... that actually points pretty strongly toward a cap issue in the AF chain or possibly the IF filter stage starting to go. the 7300 uses DSP pretty heavily so it could also be firmware related but you'd expect that to be more sudden usually.

before you crack it open i'd try a full factory reset if you havent already, like the proper one from the menu not just resetting individual settings. also check if the noise reduction or NR setting is somehow getting applied, ive seen people accidentally leave NR on a weird setting and it does exactly what you're describing on voice. go to the receive settings and just make sure NR is completely off and the passband is set wide. if none of that fixes it then yeah you're probably looking at the hardware side and honestly the IF filtering caps on these rigs do degrade, seen it a few times on older icom gear.

yeah check the NR setting first like the other guy said, i did the exact same thing to myself last year and felt like an idiot when i figured it out lol. mine was set to like NR level 8 from some contest i was messing around with and i forgot to turn it off. sounds exactly like underwater audio when its cranked up on a quiet signal.