There is provided a determining apparatus which includes a first extractor configured to extract space inside an electronic device from a model indicating the electronic device, the electronic device including a plurality of audio output apparatus and a plurality of ribs, a second extractor configured to extract the plurality of ribs from the model, a divider configured to divide the space into a plurality of chambers, the plurality of chambers being partitioned by the plurality of ribs, and a determining unit configured to determine respective rear chambers to each of the plurality of audio output apparatus so that the rear chambers satisfies a certain parameter, the rear chambers being formed by combination of one or more chambers determined by the determining unit.