Only at the output of the amplifier does a filter turn the PWM signal into the modulated oscillation that is passed on to the loudspeaker. This step is crucial for the quality level. This is because such filters usually also have an influence in the time domain. Different frequencies pass through the filter in different times. However, such a spread in what must happen at the same time in a musical sense should be avoided as far as possible. This is why a great deal of expertise and development time has gone into the choice of filter. This is optimised in such a way that it fulfils its above-mentioned core task particularly well and the spread of different frequencies is kept very low.
