The number of available ray angles in PBAP can be increased by various means.
Oversampling in time to kHz doubles the number of integer-delay angles over the same range. The example of Eq.(7) on page goes from 21 to 41 angles-of-arrival across a frontal stage.
Another avenue for doubling the number of source angles is to implement a half-sample fractional-delay filter. In that case, half of the available angles require use of the filter while the other half require no interpolation filter.
Generalizing, given fractional-delay filters, with the th filter providing fractional delay samples, , the number of available arrival angles is increased by the factor . A benefit of a fixed grid of available angles is that each fractional-delay filter can be individually designed and optimized for the delay it provides. Three such filters ( ) suffice to provide approximately complete perceptual resolution in the example of Eq.(7).