diacoustics

from The Century Dictionary.

• noun The science or doctrine of refracted sounds; the consideration of the properties of sound refracted by passing through media of different density. Also called diaphonics.

from the GNU version of the Collaborative International Dictionary of English.

• noun That branch of natural philosophy which treats of the properties of sound as affected by passing through different mediums; -- called also diaphonics. See the Note under acoustics.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun The science concerned with the properties of sound as affected by passing through different mediums; diaphonics.