Only detailed explanation of Shelf Filters for Ambisonic Decoders in the universe.
Idiot's Guide to designing Ambisonic Decoders. Derives the impulse responses of the Shelf Filters in this directory. This version corrects the Rectangular decoder & adds IIR Shelf & Distance Compensation Filters. Also Dual Band Shelfs.
You can download the document (it's a Word document contained in a Zip file) below, and also the various Wave files mentioned in it.