VHAP exploits a psychoacoustic phenomenon called the phantom image elevation effect to virtual place a phantom source over the upper-hemisphere using only three or four loudspeakers at the ear level. The VHAP technology has been developed by Dr Hyunkook Lee and Dr Dale Johnson of the APL at the University of Huddersfield. The VST plugin has been written by Maksims Mironovs.
The plugin is freely available under the CC-BY-4.0 license. A Reaper session template is also included in this release.
VHAP can be used to render virtually elevated sound images in mixing or upmixing for the conventional 5.1 format as well as in the “cross” quadraphonic format. Originally, it requires four loudspeakers arranged in the cross layout, but our recent study found that, if the target elevated positions lie within the front upper-hemisphere or at typical height loudspeaker positions (azi ±45° and 135°/ele ±45°), VHAP works equally well with just three speakers at the front centre, rear left and rear right loudspeakers of the 5.1 setup.