Mobile Platform Acoustic-Frequency Environmental Tomography
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Where we're at, 2009 Feb 2
We have Sarah's speaker-to-mic recordings, dimensions/positions of room, mics, speakers:
- raw .wav files and deconvolved .mat files
- MLS and chirp deconvolutions
- from each of 4 speakers, to each of 40 mic positions
- from some speaker-pairs, to each of 24 mic positions
Speaker-pair recordings are incomplete (only 4 of 6 possible pairs). But we could use them as sanity checks on the single-speaker recordings, instead of as primary data.
The plywood cube (actually particleboard with 2x4 framing) has been demolished. The thin-glass parts of the speakers have been demolished.
ISL still has the amplifiers, speaker drivers, and mics. One of the two Earthworks omnidirectional mics is malfunctioning and needs replacing, if we need stereo recording.
If we reconstruct a plywoodcube, prefer flush-with-wall conventional speakers over the original motivation of glass-speakers-through-cubewall-slits.
What we might publish (how much work still to do)
Corpus
Like AVICAR, but to validate room response models. No room-rebuilding, no more "research." Mention image-source, as well as several other algorithms.
Refine image-source
Add frequency dependence to wall reflection and/or air transmission, and other subtle refinements as the data suggests.
When we discussed this in early 2008, Mark guessed at least 12 months until "good-sounding" room inverse (40 dB, not just Bowon's 10 dB) in simulation, warranted before sawing particleboard.
Mask the reverberant tail by adding 10 dB SNR noise, since later echos may overlap too much to cancel rigorously.
Validate room response models
Play sounds convolved by the plywood cube's computed inverse-impulse-response. Compare the recorded results to the original unconvolved sounds. In simulations, or with a fresh plywoodcube.
A wood "phonebooth" would fit almost anywhere. Camille can imagine a larger phonebooth at ISL, though we'd have to sell Hank on building such a contraption, and we'd want to operate it remotely since it's not walking distance.
