MainComponent.h

class MyAudioSource : public AudioSource
{
public:
	MyAudioSource() {}
	void prepareToPlay(int samplesPerBlockExpected, double sampleRate) override
	{}
	void releaseResources() override
	{}
	void getNextAudioBlock(const AudioSourceChannelInfo & bufferToFill) override
	{
		for (int i = 0; i < bufferToFill.numSamples; ++i)
		{
			float sample = jmap(m_rnd.nextFloat(), 0.0f, 1.0f, -0.1f, 0.1f);
			bufferToFill.buffer->setSample(0, bufferToFill.startSample + i, sample);
			bufferToFill.buffer->setSample(1, bufferToFill.startSample + i, sample);
		}
	}
private:
	Random m_rnd;
};

class MainComponent   : public Component
{
public:
    MainComponent()
    {
		m_adman.initialiseWithDefaultDevices(0, 2);
		m_aplayer.setSource(&m_asource);
		m_adman.addAudioCallback(&m_aplayer);
		setSize (600, 400);
    }
	~MainComponent()
    {
	}
	void paint (Graphics& g) override
    {
        g.fillAll (getLookAndFeel().findColour (ResizableWindow::backgroundColourId));
		g.setFont (Font (16.0f));
        g.setColour (Colours::white);
        g.drawText ("Hello World!", getLocalBounds(), Justification::centred, true);
    }
	void resized() override
    {}
private:
	MyAudioSource m_asource;
	AudioSourcePlayer m_aplayer;
	AudioDeviceManager m_adman;
	JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (MainComponent)
};