radioplay: hw5
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.
set up audacity for mono recording from your mic (set mono mode in Preferences : Devices : Recording)
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 (set in Preferences : Recording : Playthrough). Monitor previously recorded tracks via headphones so they don't bleed into the new track. At this stage you generally want to consider normalizing the files if there's an undesired discrepancy in levels. Select a track and apply Effect : Normalize. Then, export the tracks into separate mono files. Save your work often!
with just your own voice, overdub one more track imitating any sound effects that go with the text. Export. Save the project. Quit Audacity.
listen again to your original, unpanned, dry, vocal imitations sound effects track in Audacity
gather sources and create new tracks containing the real sound effects, recording or downloading, as needed
modify this material using either Audacity's effects or passing through Chuck
see Chuck examples in the course code repository, subdirectory efx:
there are various templates for processing: pit (pitchShift), chorus, cub (cubic distortion), pan (IID,ITD,distance), reso (resonator), stretch (pitchShift with rate 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 page). 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, as before. (Refer back to instructions in HW2 Section 5 [Steps #1-3] for converting 4-channel chuck file to binaural.)
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 or (2) a chuck "score" that plays the whole radioplay. You choose.
If you do it in style 1, then you need four finished mono soundfiles, one per channel. If style 2, the "score" will play all four channels itself, performing the entire finished product. (There's also a style 3-- for anyone who's game; see below for mor information.)
4 x 1, four mono soundfiles
Use audacity to make the
four soundfiles that it plays. The last pass in Audacity will
consist of four mono tracks. Generate individual mono soundfiles
from these tracks by doing File : Export Multiple (which will
convert each track to a mono soundfile, naming and numbering the
four files automatically).
Then make your own version of
220a/ck/jukeboxPlayers/quadTurenas.ck. (You'll want to name your 4 mono files to end in "RF",
"LF", "LR", and "RR for feeding into
chuck channels 0~3, respectively, and/or modify
string Xname to point to your 4 files.)
1 x 4, one four-channel "score"
make a new chuck file
write individual functions that play the different sections of your radioplay
spork functions as needed for working developing sections
spork the functions in a time-ordered list for the final assembly
a full-featured multitrack, jack aware, digital audio workstation (DAW)
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.