Acoustic Zoning

Definition and Distinction from Conceptual Zoning

Acoustic Zoning is the codified schedule by which the ambient sound of a given volume of The Tower is assigned a permitted register and the property rights over that register conferred on a designated holder. It is administered under the Registry of Acoustic Properties and is not to be confused with Conceptual Zoning, despite the near-identical vocabulary of its founding instruments. The distinction is technical but closely guarded. Conceptual Zoning governs the assignment of permanent conceptual properties to a volume; Acoustic Zoning governs who is permitted to hear them. The Acoustic Registry of the Tower notes drily at Entry 4,112 that "the two practices were drafted by the same hand and have resented each other ever since."

The formal authority for Acoustic Zoning is Second Concordance Annex Gamma, Clauses 1–6, which articulate the principles of Conceptual Zoning in a language that Acoustic Zoning has never formally abrogated. The consequence is that the two practices cite one another's founding clauses, and the citation is technically valid.

The Lüne Code and the stratification of registers

The operative schedule is the Lüne Code, a table of twelve acoustic strata numbered A through L, each assigned to a floor or range of floors by the Department of Acoustic Phenomena. A stratum sets the loudest sustained sound a volume may emit without a draft amendment, and prescribes the ceiling of any temporary device used to produce it. The Lys-Gamma Spiral was the test case for the Code's application in plan view, where the spiral's curving corridor produces a continuous acoustic volume that no single stratum comfortably describes; the Department has maintained since Floor 9,110 that the spiral is "zoned L along its inner rail and B along its outer, and the difference is explained to visitors."

What the Code does not do is distinguish between sound intended as content and sound merely present. The Acoustic Residuals resulting from the ordinary operation of a library floor are therefore deemed, in law, to be "unzoned" — a state which the Code does not recognise. This is not a gap in the Code. It is a recognised condition of the Code being complete.

The Grievance of Clerk Vane

In the winter of 4,806, the junior clerk Elsbeth Vane, assigned to a reading hall on Floor 6,041, spent eleven days attempting to obtain a reclassification of the corridor outside her station from stratum G to stratum F. The corridor had been zoned G in 3,190 and had been silent since 4,102. Vane's contention, filed in a memorandum of twelve pages, was that a zone whose permitted sound had not been produced in seven hundred years could not reasonably be regarded as in use.

The complaint was dismissed by the Bureau of Zoning Enforcement under a clause of the Third Concordance's Annex 4, which holds that a zone's silence is itself a classified acoustic property. The Bureau's clerk of record, one Halvard Renn, endorsed the dismissal with a single annotation: "The zone is loud. It is simply not loud yet." The judgment is still cited in the Tower's own instruction on the subject. The corridor remains stratum F. Clerk Vane's memorandum is held in full by the Acoustic Registry of the Tower and is the only document in which the corridor has been described as "quiet, in the ordinary sense."

Dispute between the Concordances

Scholarly disagreement centres on the question of whether an acoustic zone may exist without a designated holder. Under the Fifth Concordance's division of properties, every zoned property is held by a person, office, or floor; a zone with no holder is a contradiction, and the register of holders must be complete. The Reform Concordance of 4,903, drafted by the Department of Acoustic Phenomena to address the Lobed Chambers, holds the reverse: that acoustic properties are held by the volume itself, that "the volume is a competent holder," and that the assignment of a holder is a fiction retained for convenience of service.

The Reform Concordance's language is cited in practice only by the Department and by its own annex. The Acoustic Laminar Rules, the Department's standing instruction, endorse the Reform reading and are generally disregarded in litigation. The Concordance of Sealed Hands, which has no acoustic subject matter, has nevertheless been cited in three of the Department's decisions for formal reasons known only to the Department. The concordance archive does not describe the relation between the two texts in any way, and two of the three decisions remain unpublished.

Crossings and the documented failure

Acoustic Zoning crosses Conceptual Zoning wherever a zone's sound is a consequence of a permanent property. The Acoustic Liaison office exists to resolve this crossing; it has been staffed by a single clerk since its establishment in 4,407 and has never once been asked to resolve it. Where a boundary between two strata is disputed, only the Acoustic Permeability Test may settle it, and the test may be run only once per boundary. The instruction accompanying the test, issued by the Department and displayed at the boundary, is not negotiable: One opening only. The boundary is not to be resealed.

Visitor guidance

The Department maintains a standing rule that no visitor is authorised to request an acoustic zone change. No mechanism exists for the request. The rule is not a prohibition on the request but a statement of its impossibility, which the Department reconciles by stating that visitors who have requested a zone change have not requested one.

See also

• Acoustic Registry of the Tower
• Conceptual Zoning
• Bureau of Zoning Enforcement
• Proclamation of Acoustic Quieture