Airflow noise in telephone handsets and methods for its reduction
Bibliographic record
Abstract
The noise in a telephone handset produced by the bursts of airflow that accompany plosive sounds such as a "p" or "t" has been investigated. Measurements have been made on a series of modified handsets, using various arrangements of ports and tubes between microphone and the exterior of the telephone mouthpiece. A narrow stream of air was used to probe the mouthpiece and the signal picked up by the microphone recorded. The use of one, two, and multiple exterior holes was considered. Two-hole approaches alleviate the static pressure buildup that occurs when a single microphone hole is used and in many cases they result in reduced noise generation; for some directions of incident airflow, though, noise can be markedly increased. This was found to be due to interaction between intersecting streams of air. By using a large number of small (less than 0.5 mm) exterior holes, the airflow noise can be reduced by over 30 dB for all incident directions of airflow. It is also beneficial to ensure that none of the exterior holes is in direct line with the sound tube leading to the microphone.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 0.001 |
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 source (direct Gemma or distilled Codex), 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".