Frequency-dependent software reverberation : design and implementation of a seven octave-band reverberator

• Main Author: Halingten, Kurtis
• Format: Others
• Language: English
• Published: 2009
• Online Access: http://hdl.handle.net/2429/15060

Software reverberators are used to superimpose reverberation on audio signals, and are used extensively in the multimedia and broadcasting industries. Several commercially-available reverberators claim to support frequency-dependent reverberation, but none have been found to implement octave-band frequency-dependent reverberation. The objective of the research reported here was to develop a reverberator capable of accurately adding reverberation to digital audio signals, with desired reverberation times from 0 to 2 seconds specified for individual octave frequency bands from 125 Hz to 8000 Hz. The physics governing diffuse reverberation have been reviewed. An indepth investigation of the methods to measure reverberation was performed. Measurement of frequency-dependent reverberation times reported in this thesis used an iterative noise-reduction algorithm combined with a novel, unique, rationalized reverberation time measurement algorithm. The properties of the common DSP filters used for superimposing reverberation have been reviewed. Several published reverberator designs have been simulated, but were found to be unsuitable to meet the research objectives. This fact, combined with the limited reverberation functionality of current audio processing software development kits, prompted the development of new reverberators. Several new software reverberators are presented. Two of these are based on a computationally efficient multirate design. A l l of the prototypes satisfied the research objective of accurate superposition of octave-band reverberation. The best design was implemented in a Microsoft Windows DLL. === Applied Science, Faculty of === Mechanical Engineering, Department of === Graduate