Teleconference systems have been widely used and mixed acoustic signals with different spatial acoustic characteristics for each place are heard. However, the perceptual impression of mixed acoustic signals containing multiple different spatial acoustic characteristics has not been sufficiently investigated. In this study, a listening test was performed to survey the difference of impression regarding the mixed acoustic signals with single and different spatial acoustic characteristics. Three instrumental signals (guitar, bass and drums) were played with a loudspeaker and recorded in three rooms. For the listening test, four mixed acoustic signals were set: 1. All instruments were captured in the small reflection room. 2. All instruments were captured in the middle reflection room. 3. All instruments were captured in the large reflection room. 4. Bass was captured in the small reflection room, drum in the middle reflection room and guitar in the large reflection room. Participants listened to No. 4 and compared it with Nos. 1, 2 and 3 and responded to which of the seven evaluation items (resonant, pleasant, natural, coherent, clear, likeable, noisy) matched. Participants perceived 1 as a pleasant acoustic signal with little reverberation and 2 and 3 as unpleasant acoustic signals with more reverberation compared to 4. It is suggested that mixed acoustic signals recorded in the small reflection room are considered the least reverberant and the most comfortable. The homogenization of spatial acoustic characteristics by suppressing reverberation from the acoustic signals captured in multiple spaces is considered to be useful in giving a pleasant impression.
