Mobile Platform Acoustic-Frequency Environmental Tomography

From SpeechWiki

Where we're at, September 2008:

We have 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, we might consider flush-with-wall conventional speakers instead of sticking to the original motivation of glass-speakers-through-cubewall-slits.

What we might publish (how much work still to do):

• An AVICAR-style corpus to validate room response models.

No room-reconstruction, no more "research". Mention image-source, as well as several other algorithms which you recently told Sarah about.

• Refine image-source by adding frequency dependence to

wall reflection and/or air transmission, and other subtle refinements as the data suggests.

When last we discussed this, you guessed at least 12 months before we got "good-sounding" room inverse (40 dB, not just Bowon's 10 dB) in simulation, warranted before rebuilding something in plywood.

Mask the reverberant tail by adding 10 dB SNR noise, since later echos may overlap too much to cancel rigorously.

• Validate room response models by playing sounds convolved by the

plywood cube's computed inverse-impulse-response, and comparing the recorded results to the original unconvolved sounds. In simulations, or with a fresh plywoodcube.

A plywood "phonebooth" would fit almost anywhere. I 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 ISL isn't walking distance.