I’m still a bit confused. i would say the radio stations are using a limited sample rate (22.05kHz) in order to save bandwidth. In theory my amplifier supports this sample rate, so it should work in passthrough mode at that sample rate. However, it only seems to work when the sample rate is upconverted to a higher standard like 44.1kHz or 48kHz in Kodi. Go figure!
I’ve put my settings back to the “Original” as a lot of my music files are from SACD or DVD-A, so are high resolution at 88kHz or 96kHz or higher, so outputting at a fixed rate would not be ideal.
Thank you @Joe_90 for doing all that testing. At least I now know I’m not the only one with the issue.
It is strange that @Betatester never had the issue on any of his 5 test devices (do not know what they were), so maybe it’s either an N2 or 922X issue.
TaNiX TX5 DLX S905X3 4/64 10/100/1000
Turewell F2 S905X2 4/32 10/100/1000
TaNiX TX3 MAX S905W 2/16 10/100
TaNiX TX3 MINI-H S905D 2/8 10/100
NexBox A95X-B7N S905X 1/8 10/100
I guess you might be on to an hardware specific issue.
As both you and I are using N2 I have raised a question on the odroid hardkernel forum regarding sample rate handling.
Check that your AVR is really support frequencies below 32kHz.
If I connect directly to tv then I had an audio, but if it connected to AVR then I don’t have audio for frequencies below 32kHz
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Interesting that you should mention 32kHz. The EDID string that Kodi gets from my Sony DN-1060 indicates that 22.05kHz (22050) is supported, but the manual is rather vague about the HDMI except to say that 32, 44.1, 48 and 96kHz are accepted through the digital jacks. I know for a fact that multichannel LPCM is accepted at up to 192kHz over HDMI, but I don’t have anything in my audio collection below 44.1kHz.
edit - the AVR can handle playback of files from the USB port or over the network and the minimum sampling rate seems to be 32kHz, so you could well be correct @boot2k3
I tested again, using my Venz V10 Pro (S905X) with CoreElec and the particular radio stations seem to be upconverted internally to 32kHz (from 22.05kHz) on the Venz and they play back normally. You may be right that my AVR doesn’t support below 32kHz or that other hardware is forcing upconversion by default to a “floor” of 32kHz whereas the N2 is not (unless I set manually it in Kodi).
Can you tell me how I can get this EDID string, so I can test at my end?
Both my SoundBar and TV must not support 22.05kHz then. It is strange that I have another radio add-on they does play the non audio stations correctly on the N2.
EDIT: Here’s a 22.05kHz audio test file that has no output on my N2 until I either enable Stereo Upmix or change the Output Configuration to fixed.
It might be those other addons do some form of software up-conversion. What other addons did you try with?
Thanks, I am going to check a few things.
@gregeeh I did some testing and found that the Radio.DE add-on handles vbr differently compared to the Radio.AU add-on. Maybe that causes an issue with the N2 audio decoder?
I don’t think it has anything to do with the various add-ons as a test audio MP3 with 22.05kHz sample rate has no audio on my N2. No add-on used at all.
Then it is most likely a hardware limitation like boot2k3 said.
I’d concur. I think the N2 is outputting 22.05kHz audio natively without up sampling, but my Sony AVR is just not handling it. My VenzV10 Pro is upsampling the audio internally to 32kHz and my Sony plays it just fine. The internal DAC in the N2+ outputs audio on the 3.5mm jack when you enable PCM output (rather than HDMI) in the Kodi audio device settings.
I also have the same problem as @gregeeh
I am using an Odroid N2 connected to a Denon 3808ci via HDMI.
With my configuration, various stations would not work with the ‘radio’ addon. In addition I had put together a m3u file of radio stations a year or two ago and that m3u worked when I ran Kodi on an Intel N2820 NUC. My troubles started when I replaced the NUC with the N2. At that point various stations stopped working in my m3u file and the radio addon.
Per the note above from @gregeeh I just changed ‘output configuration’ to ‘fixed’ and I now get audio from all stations in my m3u file and radio addon that had gone silent when I switched from the NUC to the N2.
I would prefer not to leave my output configuration to ‘fixed’ as it will not be good for other audio I have and use.
@Betatester I am hoping that the CoreELEC team are able to fix this or recommend a good way to fix this N2 problem without hurting other audio playback 
Thanks in advance!
BTW: Here are a couple of example stations that were silent prior to turning on ‘fixed’
KGO-AM 810 (San Francisco bay area)
KQED Public Radio (San Francisco bay area)
2GB-873AM (tested this station due to gregeeh’s similar issue)
I’m having a similar issue with an N2+ on .DSD data which is being output in PCM format at a sample rate too high for my Sony AVR, which tops out at 192kHz. On my S905X box on the 3.14 kernel the bit rates for audio are 32kHz at the low end of the scale and 192kHz at the high end - all of which are processed by my AVR.
I checked the manual and it says my Denon 3808CI can handle 32-192 kHz so 22.05kHz could easily be my problem as well. I have not looked at the EDID string. It would be good if we could manually override Kodi and tell it the receiver can only handle 32-192 kHz. I don’t want to override everything, just anything below 32 kHz. That way I can continue to use passthrough (setting ‘output configuration’ to ‘fixed’ turns off passthough completely).
@gregeeh The file you provided will only play for me if I set ‘output configuration’ to ‘fixed’. Well, it ‘plays’ but I get no audio unless I switch to ‘fixed’