First results of a study of the effects of the user’s hands on the frequency response and channel balance of a mobile phone hands-free loudspeaker are presented. The results show that the response variation caused by the user’s hands is high (up to 10 dB boost in narrow ranges) and highly user dependent, although general trends can be observed. The variation between users is strong especially above 5 kHz. The acoustical causes for the observed response shape are studied using a FEM model, indicating that especially the shape of the palm explains the observed features of the frequency responses. A conclusion of the results is that developing more realistic measurement methods is needed if more natural tonal balance is attempted in handheld devices.
