Extraction of infrasonic waveforms from conventional condenser microphones
Bibliographic record
Abstract
There are several commercial measurement-grade condenser microphones that are suitable for measurements down to about 0.1 Hz; however, these one-half-inch microphones reach those low frequencies with an in-line attenuator that compromises the overall dynamic range. In a previous paper [T. M. Marston and T. B. Gabrielson, J. Acoust. Soc. Am. 119, 3378 (2006)], a process was described for digital reconstruction of the lowest frequencies that avoids the attenuator and the sacrifice in dynamic range. This work has been extended to evaluate a reconstruction process for a one-quarter-inch condenser microphone, which has significantly higher low-frequency roll-off than the one-half-inch infrasonic microphones. One reason for using the one-quarter-inch microphone is its higher peak pressure limit. By modeling the preamplifier input-impedance bootstrapping and the pressure-equalization leak, extension to a few tenths of a hertz can be performed. However, the pressure-equalization leak characteristic frequency varies from microphone to microphone and with temperature. Consequently, there is a single free parameter that requires a measurement of the actual very-low-frequency response or measurement of a physically constrained reference waveform (like the N-wave from a clean sonic boom). [Work supported by the FAA/NASA/Transport-Canada Center of Excellence for Aircraft Noise and Aviation Emissions Mitigation.]
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".