Warbling distorted audio from SDR++ SDRplay RSP2 + Linux Mint 20.2

I have successfully compiled and installed SDR++ from sources on my Linux Mint 20.2 machine. I amended CMakeLists.txt to enable the SDRplay option. I also turned off Airspy and HackRF and left RTLSDR turned on. I already had the necessary SDRplay API installed as well as SoapySDR and SoapySDRplay libraries installed. These work fine with CubicSDR.

The compilation ran fine and the program was installed by finally running 'sudo make install'.

The program launches and the GUI is shown. I can choose SDRplay from the list of available sources and my RSP2 is detected and the device number is shown. Whether I receive on AM or FM, the audio is distorted and warbling. Adjusting the bandwidth from 2MHz to 8MHz helps a little but the LNA gain and possibly IF gain has to be adjusted to at least around 70% and even then it does not go away entirely and comes back after reception is paused and re-started. At these gain levels the waterfall by then looks very orange/yellow and not very useful.

I am not sure where to begin diagnosing this so need a little help.

Command prompt output:

$ sdrpp [2021-12-03 14:47:52.689] [info] SDR++ v1.0.5 [2021-12-03 14:47:52.689] [info] Loading config [2021-12-03 14:47:52.813] [info] Using OpenGL 3.0 [2021-12-03 14:47:52.927] [info] Loading icons [2021-12-03 14:47:52.933] [info] Loading band plans [2021-12-03 14:47:52.941] [info] Loading band plans color table [2021-12-03 14:47:52.946] [info] Loading modules [2021-12-03 14:47:52.946] [info] Loading /usr/lib/sdrpp/plugins/network_sink.so [2021-12-03 14:47:52.947] [info] Loading /usr/lib/sdrpp/plugins/rtl_tcp_source.so [2021-12-03 14:47:52.947] [info] Loading /usr/lib/sdrpp/plugins/sdrplay_source.so [2021-12-03 14:47:52.961] [info] Loading /usr/lib/sdrpp/plugins/radio.so [2021-12-03 14:47:52.978] [info] Loading /usr/lib/sdrpp/plugins/rigctl_server.so [2021-12-03 14:47:52.995] [info] Loading /usr/lib/sdrpp/plugins/soapy_source.so [2021-12-03 14:47:53.012] [info] Loading /usr/lib/sdrpp/plugins/discord_integration.so [2021-12-03 14:47:53.028] [info] Loading /usr/lib/sdrpp/plugins/file_source.so [2021-12-03 14:47:53.045] [info] Loading /usr/lib/sdrpp/plugins/frequency_manager.so [2021-12-03 14:47:53.061] [info] Loading /usr/lib/sdrpp/plugins/rtl_sdr_source.so [2021-12-03 14:47:53.078] [info] Loading /usr/lib/sdrpp/plugins/recorder.so [2021-12-03 14:47:53.095] [info] Loading /usr/lib/sdrpp/plugins/meteor_demodulator.so [2021-12-03 14:47:53.112] [info] Loading /usr/lib/sdrpp/plugins/audio_sink.so [2021-12-03 14:47:53.134] [info] Initializing Airspy Source (airspy_source) [2021-12-03 14:47:53.144] [error] Module 'airspy_source' doesn't exist [2021-12-03 14:47:53.144] [info] Initializing AirspyHF+ Source (airspyhf_source) [2021-12-03 14:47:53.160] [error] Module 'airspyhf_source' doesn't exist [2021-12-03 14:47:53.160] [info] Initializing Audio Sink (audio_sink) [2021-12-03 14:47:53.177] [info] Initializing BladeRF Source (bladerf_source) [2021-12-03 14:47:53.194] [error] Module 'bladerf_source' doesn't exist [2021-12-03 14:47:53.194] [info] Initializing File Source (file_source) [2021-12-03 14:47:53.211] [info] Initializing Frequency Manager (frequency_manager) [2021-12-03 14:47:53.227] [info] Initializing HackRF Source (hackrf_source) [2021-12-03 14:47:53.244] [error] Module 'hackrf_source' doesn't exist [2021-12-03 14:47:53.244] [info] Initializing LimeSDR Source (limesdr_source) [2021-12-03 14:47:53.261] [error] Module 'limesdr_source' doesn't exist [2021-12-03 14:47:53.261] [info] Initializing Network Sink (network_sink) [2021-12-03 14:47:53.277] [info] Initializing PlutoSDR Source (plutosdr_source) [2021-12-03 14:47:53.294] [error] Module 'plutosdr_source' doesn't exist [2021-12-03 14:47:53.294] [info] Initializing RTL-SDR Source (rtl_sdr_source) Detached kernel driver Found Fitipower FC0012 tuner Reattached kernel driver [2021-12-03 14:47:53.783] [info] Initializing RTL-TCP Source (rtl_tcp_source) [2021-12-03 14:47:53.784] [info] Initializing Radio (radio) [2021-12-03 14:47:54.281] [info] RtAudio stream open [2021-12-03 14:47:54.281] [info] Initializing Recorder (recorder) [2021-12-03 14:47:54.356] [info] Initializing Rigctl Server (rigctl_server) [2021-12-03 14:47:54.385] [info] Initializing SDRplay Source (sdrplay_source) [2021-12-03 14:47:54.790] [info] New DSP samplerate: 2000000.0 (source samplerate is 2000000.0) [2021-12-03 14:47:54.791] [info] Updating FFT DSP settings: Keep: 65536, Skip: 34464 [2021-12-03 14:47:55.514] [info] Initializing SoapySDR Source (soapy_source) [INFO] devIdx: 0 [INFO] hwVer: 2 [INFO] rspDuoMode: 0 [INFO] tuner: 1 [INFO] rspDuoSampleFreq: 0.000000 [2021-12-03 14:47:56.669] [info] Setting sample rate to 62500.0 [2021-12-03 14:47:56.669] [info] New DSP samplerate: 62500.0 (source samplerate is 62500.0) [2021-12-03 14:47:56.670] [info] Updating FFT DSP settings: Keep: 3125, Skip: 0 [2021-12-03 14:47:56.670] [info] Initializing SpyServer Source (spyserver_source) [2021-12-03 14:47:56.671] [error] Module 'spyserver_source' doesn't exist [2021-12-03 14:47:56.671] [info] Loading color maps [2021-12-03 14:47:56.672] [info] Loading /usr/share/sdrpp/colormaps/electric.json [2021-12-03 14:47:56.672] [info] Loading /usr/share/sdrpp/colormaps/viridis.json [2021-12-03 14:47:56.673] [info] Loading /usr/share/sdrpp/colormaps/greyscale.json [2021-12-03 14:47:56.673] [info] Loading /usr/share/sdrpp/colormaps/classic.json [2021-12-03 14:47:56.674] [info] Loading /usr/share/sdrpp/colormaps/classic_green.json [2021-12-03 14:47:56.674] [info] Loading /usr/share/sdrpp/colormaps/websdr.json [2021-12-03 14:47:56.675] [info] Loading /usr/share/sdrpp/colormaps/gqrx.json [2021-12-03 14:47:56.676] [info] Loading /usr/share/sdrpp/colormaps/inferno.json [2021-12-03 14:47:56.676] [info] Loading /usr/share/sdrpp/colormaps/magma.json [2021-12-03 14:47:56.677] [info] Loading /usr/share/sdrpp/colormaps/plasma.json [2021-12-03 14:47:56.678] [info] Loading /usr/share/sdrpp/colormaps/turbo.json [2021-12-03 14:47:56.699] [info] New DSP samplerate: 2000000.0 (source samplerate is 2000000.0) [2021-12-03 14:47:56.700] [info] Updating FFT DSP settings: Keep: 65536, Skip: 34464 [2021-12-03 14:47:56.700] [info] SDRPlaySourceModule 'SDRplay Source': Menu Select! [2021-12-03 14:47:56.700] [info] New DSP samplerate: 2000000.0 (source samplerate is 2000000.0) [2021-12-03 14:47:56.700] [info] Updating FFT DSP settings: Keep: 65536, Skip: 34464 [2021-12-03 14:47:57.155] [info] RtAudio stream open [2021-12-03 14:47:57.177] [info] Updating FFT DSP settings: Keep: 65536, Skip: 34464 [2021-12-03 14:47:57.177] [info] Updating FFT DSP settings: Keep: 65536, Skip: 34464 [2021-12-03 14:47:57.179] [info] Updating FFT DSP settings: Keep: 65536, Skip: 34464 [2021-12-03 14:47:57.180] [info] SDRPlaySourceModule 'SDRplay Source': Tune: 100000000.0! [2021-12-03 14:47:57.180] [info] Running post-init for Audio Sink [2021-12-03 14:47:57.180] [info] Running post-init for File Source [2021-12-03 14:47:57.180] [info] Running post-init for Frequency Manager [2021-12-03 14:47:57.180] [info] Running post-init for Network Sink [2021-12-03 14:47:57.180] [info] Running post-init for RTL-SDR Source [2021-12-03 14:47:57.180] [info] Running post-init for RTL-TCP Source [2021-12-03 14:47:57.180] [info] Running post-init for Radio [2021-12-03 14:47:57.180] [info] Running post-init for Recorder [2021-12-03 14:47:57.180] [info] Running post-init for Rigctl Server [2021-12-03 14:47:57.180] [info] Running post-init for SDRplay Source [2021-12-03 14:47:57.180] [info] Running post-init for SoapySDR Source [2021-12-03 14:47:57.180] [info] Ready. [2021-12-03 15:00:30.038] [info] New DSP samplerate: 8000000.0 (source samplerate is 8000000.0) [2021-12-03 15:00:30.044] [info] Updating FFT DSP settings: Keep: 65536, Skip: 334464 [2021-12-03 15:00:43.820] [info] SDRPlaySourceModule 'SDRplay Source': Start! [2021-12-03 15:00:43.846] [info] SDRPlaySourceModule 'SDRplay Source': Tune: 100000000.0! [2021-12-03 15:00:47.736] [info] SDRPlaySourceModule 'SDRplay Source': Tune: 112200000.0! [2021-12-03 15:00:48.922] [info] SDRPlaySourceModule 'SDRplay Source': Tune: 105000000.0! [2021-12-03 15:00:51.122] [info] SDRPlaySourceModule 'SDRplay Source': Tune: 98000000.0! [2021-12-03 15:01:04.041] [info] SDRPlaySourceModule 'SDRplay Source': Stop! [2021-12-03 15:01:06.201] [info] New DSP samplerate: 4000000.0 (source samplerate is 4000000.0) [2021-12-03 15:01:06.207] [info] Updating FFT DSP settings: Keep: 65536, Skip: 134464 [2021-12-03 15:01:08.146] [info] SDRPlaySourceModule 'SDRplay Source': Start! [2021-12-03 15:01:08.172] [info] SDRPlaySourceModule 'SDRplay Source': Tune: 98000000.0! [2021-12-03 15:01:10.862] [info] SDRPlaySourceModule 'SDRplay Source': Stop! [2021-12-03 15:01:13.807] [info] New DSP samplerate: 8000000.0 (source samplerate is 8000000.0) [2021-12-03 15:01:13.813] [info] Updating FFT DSP settings: Keep: 65536, Skip: 334464 [2021-12-03 15:01:16.321] [info] SDRPlaySourceModule 'SDRplay Source': Start! [2021-12-03 15:01:16.346] [info] SDRPlaySourceModule 'SDRplay Source': Tune: 98000000.0! [2021-12-03 15:01:31.816] [info] SDRPlaySourceModule 'SDRplay Source': Stop! [2021-12-03 15:01:34.744] [info] SDRPlaySourceModule 'SDRplay Source': Start! [2021-12-03 15:01:34.769] [info] SDRPlaySourceModule 'SDRplay Source': Tune: 98000000.0! [2021-12-03 15:01:50.965] [info] SDRPlaySourceModule 'SDRplay Source': Stop! [2021-12-03 15:01:53.860] [info] SDRPlaySourceModule 'SDRplay Source': Start! [2021-12-03 15:01:53.885] [info] SDRPlaySourceModule 'SDRplay Source': Tune: 98000000.0! [2021-12-03 15:02:20.385] [info] SDRPlaySourceModule 'SDRplay Source': Stop! [2021-12-03 15:02:22.817] [info] SDRPlaySourceModule 'SDRplay Source': Start! [2021-12-03 15:02:22.842] [info] SDRPlaySourceModule 'SDRplay Source': Tune: 98000000.0! [2021-12-03 15:02:34.170] [info] SDRPlaySourceModule 'SDRplay Source': Stop! [2021-12-03 15:02:36.753] [info] SDRPlaySourceModule 'SDRplay Source': Start! [2021-12-03 15:02:36.804] [info] SDRPlaySourceModule 'SDRplay Source': Tune: 98000000.0! [2021-12-03 15:03:00.767] [info] SDRPlaySourceModule 'SDRplay Source': Stop!

AlexandreRouma / SDRPlusPlus

Warbling distorted audio from SDR++ SDRplay RSP2 + Linux Mint 20.2 #531