Its only at the amplifier’s output , where a filter creates the modulated oscillation from the PWM signal, as it must be passed on to the loudspeaker. This step is quite decisive for the quality level. Such filters usually also have an influence in the time domain. Different frequencies pass through the filter in different times. However, such spreading of what must happen precisely at the same time in the musical sense has to be avoided as far as possible. That’s why a lot of know-how and development time went into the choice of filter. This filter is optimized to fulfil its above-mentioned core task exceptionally well, while the spread of different frequencies is kept very low.