The sound field generated by a distributed mode loudspeaker (DML) can exhibit some characteristics that may be unfamiliar to conventional cone loudspeaker designers. In particular, the modal vibration of the diaphragm gives rise to a wide range of directivity patterns dependent on the specific design of the unit. This paper outlines some of the possible behaviors and the measurement techniques that should be employed to capture each case. In particular, the features of a diffuse sound field are discussed. It is shown that this can give rise to a pressure response that may vary significantly over a small angle and frequency scale. Here a multipoint measurement, such as a spatial average or acoustic power, gives a more representative assessment than measuring just the acoustic sound pressure level at a single point. In addition, the fine detail of the response may be characterized by a spatially averaged correlation function, giving a measure of the diffusivity that is complementary to more standard measures of energy distribution.