another attempt at a fix

decoder_modules/radio/src/radio_module.h

@@ -318,13 +318,12 @@ private:
 
     void selectDemod(demod::Demodulator* demod) {
         // Stopcurrently selected demodulator and select new
-        afChain.stop();
+        afChain.setInput(&dummyAudioStream, [=](dsp::stream<dsp::stereo_t>* out){ stream.setInput(out); });
         if (selectedDemod) {
             selectedDemod->stop();
             delete selectedDemod;
         }
         selectedDemod = demod;
-        afChain.start();
 
         // Give the demodulator the most recent audio SR
         selectedDemod->AFSampRateChanged(audioSampleRate);