Have you tried another cable? Maybe as the cables get older they get brittle and may have some interference.

 

Yes. I've tried multiple cables. I've used the hyundai provided iPod cable and several AUX and headphone chords.

 

I haven't had good luck with AUX cables in general with any radio in any car - typically the connector is prone to dust and can lead to crackling and intermittent static and drop-outs like you describe - the static varying with RPM seems odd, though ...

You have a couple of options ...

Assuming your car has USB also - the easiest option might be to rip the podcasts to USB and use that - either with the phone or with a USB thumb drive.

Otherwise - there isn't much with the AUX port itself - but I don't know if it is the port or the radio - probably the port.

You could try cleaning the port with some electrical contact cleaner.

If that doesn't work, I think the ports are around $30 on E-bay, the radios are around $50, or you could get an aftermarket radio with it's own AUX port.

 

I've got the same issue with accent 2017, but with usb port, once you accelerate, it's voltage drops that disconnects the USB and get it back on, tried few usb/aux ports, same problem persisted, it went away with new radio for couple of hrs, then it got back,same issue back as before! So it is so confusing, got back the old radio, again worked for couple of hrs and got the same problem back... I even went to the extreme, changed the alternator voltage regulator and got the same issue!!!
Decided to use cds instead kicking myself to solve it!!!

 

And one other thing, that I've forgotten to mention, I went really to the extreme, external adapter to provide the required 5 volts instead of the radio... still got that issue unsolved!!!