periphonic
/ˌpɛrɪˈfɒnɪk/adjective
Of sound reproduction: involving speakers at different heights so as to add a vertical distribution of sound to the horizontal one of stereophony.
Origin
1970s; earliest use found in The Times. From peri- + -phonic. Compare Hellenistic Greek περιϕωνεῖν to sound around, re-echo.