AES Fall Convention 2022

Ambisonic spatial room impulse responses (SRIRs) can be used in digital reverberators to create three-dimensional artificial reverberation.  Previous research has shown that mixing the spatially-filtered outputs from two spaced higher-order ambisonic (HOA) microphone arrays can improve the listeners perception of ambience sound compared to a single HOA array in music recording applications. Perceptual attributes used to describe SRIRs may be similarly influenced by this technique. In the present study, a method for deriving a composite HOA SRIR from two spaced HOA microphone arrays is described. Several microphone spacing distances commonly used in stereophonic recording were measured (17cm, 34cm, and 68cm) and compared to a single-array control. Subjective evaluations were conducted over a 7.0.4 loudspeaker array and headphones (binaural decoding). The stimuli were rated based on perceived clarity of background and early spatial impressions, environment / room width, sensation of physical presence, and overall listening experience. Results show the technique may improve the clarity of early spatial impressions and perceived environment width under certain conditions. Generally, participants had a difficulty discriminating between array spacings. The study suggests that there are potential perceptual benefits to this approach, but further studies involving additional room and source types is needed.