radioplay: hw5

radioplay with localization (azimuth / distance panning) and effects

Due 11:59pm on Friday, November 19 in the Homework Factory

The assignment is to create a short radioplay with a recorded text, quad audio and various sound effects. Shoot for a duration of around 120 secs (plus or minus 30). As before, the turned in file will be a binaural recording, intended for headphones. Techniques include localization with interaural intensity difference (IID), interaural time difference (ITD), Schroeder-style reverb, and processing for time and pitch transposition.

True binaural recording uses stereo mics listening outwards from inside your ears to capture as closely as possible the exact waves your ear canals receive. The binaural technique captures filter (transfer function) differences caused by body parts shadowing and reflecting sounds arriving from various directions: the ear flaps (pinnae), head, shoulders, etc. Played back over headphones, it preserves the IID and ITD cues that are basic to sound localization. We'll modulate sound locations in the quad speaker setup using panning in the digital audio editor ardour. We'll then process the quad signals into a stereo binaural file.

Early work in binaural recording was accompanied by predictions that its superior imaging would attract a following and everyone would eventually listen through headphones. A few decades later, a huge amount of material in binaural has yet to happen, but certainly headphones are ubiquitous. Playing binaurally-encoded sounds over a stereo loudspeaker system doesn't result in either good binaural or good stereo, and that's one thing that's holding back wider use. The earbud phenomenon is begging for binaural content. For a position paper on where this may be going see Jens Blauert's AES Heyser Lecture. He makes a provocative case for binaural as a part of an increasingly realistic synthetic world combined with many other contributing modalities.

One artist whose work leverages the medium is Janet Cardiff. She composes site-specific 3D audio narratives with spine-tingling interplay of real and phantom presences, binaurally produced. Her telephonecall from SFMOMA 2001 is a benchmark piece that opens up the possibilities of what you might expect to compose for mobile devices. The composition led participants by the nose through the gallery, each holding a camcorder in playback mode with a pre-recorded self-guided tour. You'd turn a corner and someone in your earphones would be there singing in the space (acoustically convincing, so that you could point to them) only they weren't there then, but at some other point in time, past, alternative present, or future.

Our approach starts with composing spatialized sound for the quad speaker arrangement. Pick a short text which might be a monologue, group dialog, or whatever you want, but it should constitute some sort of a script (feel free to write it from scratch, if you'd like). You'll use your own voice and possibly other voices in combination depending on the text to be read. If it's a dialog invite others to read, or if you're theatrically inclined, use your voice for the different characters. First, second or third person narratives are all fine and we'll get a variety from the class.

Hint #1: timing in the dialog track of a radioplay is different than straight reading and you'll need to leave gaps which will provide space for sound effects where appropriate. Pace your reading accordingly.

Hint #2: this assignment involves many, many intermediate files, so invent a descriptive naming scheme and stay consistent.

source material

localization & sound effects, time-warping, transposition

final assembly


Submit hw5.html to the homework factory with a link to the final binaural wav file. Also make links to other wav files that were used to create the original 4-channel version [i.e. (1) four mono soundfiles and chuck file used to plqy them in 4 channels or (2) one four-channel chuck "score" or (3) wav files used in ardour.]
If you'd like, you can also include any comments about the hw to the teaching staff.