This article provides an overview of further methods for producing hybrid natural-synthetic spectra with adaptive frequency modulation (AdFM). It focuses on three different techniques for the generation of asymmetric spectra based on single-sideband FM, asymmetric FM and Split-sideband synthesis. The first two techniques are applied to the variable delay line implementation of AdFM, whereas the third is based on an extension of the heterodyne method. The article discusses the principles involved in each synthesis technique in good detail, providing one reference implementation for each. A number of examples are discussed, demonstrating the possibilities for a variety of digital audio effects applications.