Phonon, play sound on key press

[ale6111]

Hi,
I need to play a sound when a key on keyboard is pressed, I have this:

Phonon::MediaObject *clickObject = new Phonon::MediaObject(this);
clickObject->setCurrentSource(Phonon::MediaSource("Click/sound.wav");
Phonon::AudioOutput *clickOutput = new Phonon::AudioOutput(Phonon::MusicCategory, this);
Phonon::createPath(clickObject, clickOutput);

Phonon::MediaObject *clickObject = new Phonon::MediaObject(this);
clickObject->setCurrentSource(Phonon::MediaSource("Click/sound.wav");
Phonon::AudioOutput *clickOutput = new Phonon::AudioOutput(Phonon::MusicCategory, this);
Phonon::createPath(clickObject, clickOutput);

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and

void MainWindow::keyPressEvent(QKeyEvent *event)
{
    clickObject->play();
}

void MainWindow::keyPressEvent(QKeyEvent *event)
{
    clickObject->play();
}

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but no sound is played?
Where am I wrong?
Thanks.