One of the most noticeable perceptual effects of interchannel crosstalk in multichannel microphone technique is an increase in perceived source width. The relationship between the perceived source-width-increasing effect and its physical causes was analysed using an IACC-based objective measurement model. A description of the measurement model is presented and the measured data obtained from stimuli created with crosstalk and those without crosstalk are analysed visually. In particular, frequency and envelope dependencies of the measured results and their relationship with the perceptual effect are discussed. The relationship between the delay time of the crosstalk signal and the effect of different frequency content on the perceived source width is also discussed in this paper.