Demo radio app high pitched whine/ring

There is a prominent whining/ringing noise when playing the radio from the demo radio app, on all channels.

When I do it from the command line:

it sounds fine. 200000 has the ringing noise, 256000 does not. I'm thinking it might use some value by default that isn't used in the radio app's implementation of rtl_fm. I can't spot it on my skim through rtl_fm.c's original source vs. the one in the radio app.

I also ran the SDR# app in Windows to confirm it wasn't a problem with the dongle

I've tried to edit the app to allow me to configure the sample rate (instead of hardcoding to 200000, I read a value from /etc/xdg/AGL.conf, currently set to 256000, equivalent to s 256000 on the rtl_fm command line–I can submit a patch for that if you'd like) but it doesn't get rid of the ringing the way it does on the command line.

I can't spot what's the difference between the way rtl_fm does it and the way the radio app does it.