def update(frames):
    if self.stream.is_active():
        slice = self.left.get_sample_slice(frames, frames + self.window)
        self.stream.write(slice.raw_data)
        z = np.array(slice.get_array_of_samples())
        zft = np.abs(np.fft.fft(z / max(z))) / (self.window * 4)
        lf.set_xdata(x)
        lf.set_ydata(y)
        lf.set_3d_properties(zft)
        lf2.set_xdata(x)
        lf2.set_ydata(y)
        lf2.set_3d_properties(z / 1000000)

    return lf, lf2,