The Droning in Stack 77theta Floor 9401

Description

The Droning in Stack 77theta Floor 9401 is an acoustic phenomenon recorded on Floor 9401 within Sector Theta, attributed to the shelving designated Stack 77theta. The sound is a continuous low-frequency drone, measured between 31 and 34 hertz, audible throughout the stack's fourteen bays and diminishing to inaudibility approximately nine metres beyond the stack's eastern threshold. First catalogued in the winter of the Third Recension, it remains under standing observation by the Containment Directorate of Floor -17, Annex Theta.

The droning is distinct from, though frequently confused with, the sound catalogued under Concordance Annex 17-δ as the "droning hum" of Yawning Wood. The two are separated by 8,461 floors and by the Ordinance Theta-4 humidity régime, and are not considered related by the current consensus, though a minority position persists (see Disputed provenance).

Location and access

Stack 77theta occupies the northern half of Floor 9401, a floor notable for its non-sequential numbering and for the absence of any corresponding entry in Registry Theta-7 until the Second Addendum. The stack comprises 62 bays of standard depth, of which bays 1–14 are designated the "audible range." Access is by the eastern stair from Floor 9400 and by the freight aperture serving Floors 9395–9410.

Under Clause Theta-12.4.7, visitors are admitted in pairs and are required to sign the Floor 9401 register at the eastern threshold. Loud conversation within the audible range is not prohibited, but is described in the register as "unhelpful."

History of observation

The droning was first recorded by Sub-Registrar Halvid of the Chronological Compliance Bureau during a routine moisture survey conducted under Ordinance Theta-4. Halvid's initial report, filed 14th of the month of Stacking, described "a pressure in the ears and a sense that the shelves were further apart than the plan indicated." The report was filed without comment and did not resurface for eleven years.

Systematic observation began after the Expeditionary Party Theta-9 transit, during which the party's chronometers on Floor 9401 were found to lose an average of four seconds per hour relative to the Map Room standard. The discrepancy was never reconciled, and Floor 9401 was quietly added to the list of floors exempted from Concordance Theta timing audits.

In the winter of the Provisional Stack Relocation campaign, bays 31–46 were emptied to receive material displaced by the move of the Stack of Ephemeral Certainties from Floor 317 to Floor 404. The droning was observed to intensify during the empting and to return to baseline within nine days of restocking. The supervising clerk, Voss-Alder, filed a note attributing the change to "the shelves having less to hold," which was amended in the margin to "the shelves having less to hold onto" by an unidentified hand.

Acoustic properties

The sound has three recurring components: a fundamental tone near 32 hertz, a secondary at approximately 63 hertz, and an irregular modulation with a period of roughly 40 minutes. The modulation has been recorded 219 times without repetition. Two attempts to reproduce it in the acoustics annex of Spiral Theta failed; both were terminated after the test tone was found to be drifting downward at a rate inconsistent with the apparatus.

The Aural Conduit Theta-14 does not serve Floor 9401, and no conduit survey has been conducted on the floor. A request to extend the survey line was declined in the year of the Fifth Amendment on the grounds that "the droning is not a duct."

Disputed provenance

The origin of the droning is disputed. Three positions are on record:

• That the sound originates in the substructure beneath Floor 9401 and is transmitted through the shelving. Held by the Containment Directorate of Floor -17, Annex Theta, which maintains two permanent observers.
• That the sound is produced by the shelving itself under load. Held by the scriptorium of Sub-Class Theta-Gamma, citing the intensity change during the Provisional Stack Relocation.
• That the sound is a property of the floor number rather than of the stack, and would be audible on Floor 9401 with the stack removed. Held by no standing office, but recorded in the margin of three separate registers since the Second Recension.

The Concordances are silent on the matter. Diagram Theta marks Floor 9401 with a plain circle and no annotation, which the scriptorium of Sub-Class Theta-Gamma has argued is itself significant, and which the Containment Directorate has argued is simply how Diagram Theta marks floors about which nothing is known.

Current status

Observation continues under the joint sign of the Containment Directorate and the Chronological Compliance Bureau. The register at the eastern threshold records 14 to 30 visitors per month, the majority of whom sign, listen for between four and eleven minutes, and sign out again. No adverse effects have been documented. Visitors are reminded that Floor 9401 is served by only one freight aperture, and that the aperture does not stop between Floors 9395 and 9410.