Beginner trying to follow tutorial, no sound in output?

Hi, I am trying to follow the tutorial called “Tutorial: Processing audio input”.
My source code is here:

Right now I get no error whatsoever, but when I run the app, I was supposed to hear output some noise on top of whatever comes in the input channel, but I hear nothing when moving the slider? Can someone please guide me, what am I doing wrong?

Thank you so much.
Best regards,


is at the end of your processBlock … if that does what I think it does … you’ll get a lot of silence.

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thx a lot for the reply, I also saw that after I posted, and commented it out, still silence

Right now I am looking at potentially trying to call open() and start() on the AudioIODevice resulted from this line: auto *device = deviceManager.getCurrentAudioDevice();, perhaps it cant play without being explicitly started? Not sure. Still, I was expecting sound in the default output device, as the tutorial says it should happen

just tried debugging now, and it seems that neither prepareToPlay() nor getNextAudioBlock() ever get called. Strange, since I have read that when calling setAudioChannels(2, 2); that in turn calls prepareToPlay - well , it never happens.

edit: oh wow, I got an errror during debugging, inside the setAudioChannels() method:

{data=0x000001d50cbbe150 “The input and output devices don’t share a common sample rate!” }

oh wow, was this environment dependant. interesting

have now set my own sampleRate and saved it, so the error is gone. It still does not enter the prepare method, so the hunt continues.