Typical attempts to collect sets of head-related transfer functions (HRTFs) attempt to remove from the derived transfer functions the acoustical properties of the sound source used to make those measurements. This is done so that the directionally-dependent variations in the binaural response at the receiver's location can be independently characterised. For sound sources that are far from the receiver's location, this is appropriate and relatively straightforward to achieve. However, at close range (e.g., at distances between source and receiver position of less than 1 meter), characterising the variation in derived transfer functions that is dependent upon the acoustical characteristics of an orally-radiated source becomes potentially useful. The measurements reported here attempted to capture both source and receiver characteristics for a particular case, that in which the sound source is radiated from the mouth of an snthro-pomorphic manikin, and is received at the ear of a nearby manikin. Substantial range-dependent variation in the measured transfer functions was observed, clearly due to the presence of reflections between the surfaces of the source manikin and the receiver manikin's head. These results have implications for spoken telecommunication applications employing headphone-based virtual acoustic simulations.
展开▼
