Acoustical properties of homogeneous planar surfaces in room acoustics: A theoretical review
Bibliographic record
Abstract
This work reviews the fundamental boundary conditions used in room acoustics from a theoretical perspective. In particular, it is assumed that sound propagates in air as plane waves and the boundaries are planar walls. Moreover, the walls are assumed to be infinite in lateral extent and have uniform properties along their surface. These two conditions ensure that sound waves are reflected wholly specularly, as opposed to being scattered as well; the assumption of infinite lateral extent avoids scattering from the edges of the walls, and the assumption of uniform properties avoids scattered radiation caused by the inhomogeneity of the wall. Parameters used in describing the acoustical properties of the walls are introduced and, using the wave equation, expressions are derived for them in terms of the wall impedance. Theoretical relations between the parameters are then discussed based on (i) physical restrictions such as energy conservation and the causality condition and (ii) simplifying assumptions used in room acoustics such as local reaction of surfaces and the minimum-phase condition. Finally, some practical aspects of these theoretical relations are discussed using simple examples.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.002 | 0.001 |
| Bibliometrics | 0.004 | 0.005 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.003 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.002 |
| Insufficient payload (model declined to judge) | 0.003 | 0.003 |
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".