 Also, as DAB transmits digital audio, there is no hiss with a weak signal, which can happen on FM.However, radios in the fringe of a DAB signal can experience a "bubbling mud" sound interrupting the audio or the audio cutting out altogether.Due to sensitivity to doppler shift in combination with multipath propagation, DAB reception range (but not audio quality) is reduced when travelling speeds of more than 120 to 200 km/h, depending on carrier frequency.