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). 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 control written in ChucK. 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.

Using a decent soundcard, in Audacity: for this assignment, high-quality audio is essential and most laptop or mobile mic inputs are too noisy. Please use an outboard soundcard like those available at CCRMA.

1. Set up the preference for mono recording from your mic:
   Preferences > Devices > Recording > Channels > 1 (Mono)
2. Record a dialog track reading the text you've chosen. If more than one character is needed, then read these other voices subsequently into separate tracks, using Audacity's overdub mode:
   Preferences > Recording > Overdub(Check)
3. Monitor previously recorded tracks via headphones so they don't bleed into the new track.
4. You generally want to consider normalizing the files if there's an undesired discrepancy in levels. Select a track and apply normalization:
   Effect > Normalize...
5. With just your own voice, overdub one more track imitating any sound effects that go with the text.
6. Then, export the tracks into separate mono files. Select and export one by one:
   File > Export Selection...
7. Save your Audacity project and quit. Save often!

Listen again to your original, unpanned, dry, vocal imitations sound effects track. Gather sources and create new tracks containing the real sound effects, recording or downloading as needed.

Modify this material using two options:

1. Audacity's effects
   : see Audacity's Effect menu (online reference)
2. Passing through ChucK
   : see ChucK code examples in the course code repository, subdirectory effects
   • There are various templates for processing: pit(pitchShift), chorus, cub(cubic distortion), pan(IID, ITD, distance), reso(resonator), stretch(pitch shift with speed change).
   • These are variously labeled as: ADAC(realtime I/O), FileDAC(file to realtime output), File(read/write file).

Pan and reverberate each sound effect track as appropriate for your radioplay.

First, think through the work flow in reverse:

• Ultimately, there's going to be a binaural stereo final product (for the homework factory submission). To create it, the last step is to play the content you've developed in four channels into the binaural.pssp inputs while recording the stereo binaural output. (Refer this instruction for converting 4-channel chuck file to binaural recording.)
• A four-channel chuck player is needed that plays your whole project. This can be in the style of either:
  1. A simple four-channel soundfile player
     : for this configuration, you need four finished mono soundfiles, one per channel. (4x1, four mono soundfiles)
  2. A ChucK "score" that plays the whole radioplay.
     : the "score" will play all four channels itself, performing the entire finished product. (one four-channel "score")

These files are required to be visible on your 220a directory by due date.

• hw2.html
  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.
• ChucK codes and sound files (choose one depending on your style)
  1. Four mono sound files and a ChucK code used to play them in 4 channels.
  2. One four-channel chuck "score" with sound files.

If you'd like, you can also include any comments about the homework to the teaching staff.