Tonal Residue

Tonal Residue is the class of auditory phenomena which persist in a floor's acoustic record after the originating source, instrument, or occasion has been withdrawn, and which cannot be assigned to the “Tonal Ground,” proper. It is distinguished from Auditory Residue on the grounds of persistence and from Perceptual Residue on the grounds of attribution: Tonal Residue is heard by the ear and, more problematically, by the archive itself. Its handling is governed principally by Concordance 89, "Regulations Pertaining to Tonal Residue in Sub-Shelf 89.beta," whose numerous annexes have made the subject one of the most heavily legislated and least understood in the Tower.

Definition and classification

A sound becomes Tonal Residue when two conditions hold: it is no longer produced, and it is still present. The surviving acoustic profile is measured against the floor's certified Tonal Sigils and, on floors where those have been mislaid, against the archivist's unaided recollection, a practice condemned in Librarian Provisional Ordinance 14 but never discontinued.

Residue is graded on the Silentium Scale, a nine-step interval running from Grade I (audible to trained staff only) to Grade IX (audible to staff not present). Grade IV is the threshold at which a floor must file notice, and Grade VI the threshold at which the floor may no longer be entered without an escort from the Office of Acoustic Survey. The Scale is not a measure of loudness. It is a measure of how many persons can be reasonably said to have heard something they were not there for.

Concordance 89 and the question of custody

Concordance 89 establishes the principle of tonal sovereignty: that a residue belongs to the floor which holds it and may not be removed, exchanged, or lent, even to a floor of higher grade which could presumably make better use of it. The principle has never been challenged in writing. It has been challenged in practice by the systematic theft of residue, which is difficult to prove and impossible to prevent, since the object stolen is one which by definition cannot be carried.

Custody disputes are heard by the Sub-Shelf Tribunal, which has developed a body of precedent concerning what constitutes "holding" a residue. In the matter of the Fourth Landing Ceiling Hum, the Tribunal ruled that a residue is held by the floor beneath the surface producing it, awarding the Hum to Floor 212 against the claims of Floor 211, where it was heard. Floor 211 has not appealed. It has, however, continued to hear it.

The Sympathetic problem

The Echo Amendment to the Residue Schedule recognized a subordinate category, Sympathetic Residue, in which a tonal profile is imposed on a space by the expectations of those who enter it. The amendment was intended to be narrow. Technicians of the Residue, who classify Sympathetic Residue as a Class II derivative, have argued for decades that the category is doing work the amendment never contemplated. Their position paper of 9 Frost, Memorial on the Second Derivative, proposes that all Tonal Residue is in some degree sympathetic, since a residue heard by no one cannot be said to persist, and a residue heard by someone is by that fact heard in expectation of it. The Office of Acoustic Survey rejects the memorial as "a counsel of despair dressed in schedule form" (Survey Reply to the Memorial, para. 3).

"A residue which requires an audience is not a residue. It is a performance, and the Tower does not pay for performances."

— Overview Memo on the Second Derivative, Office of Acoustic Survey

The Matter of Clerk Ossava

In the winter of the year recorded as 4 Frost, a filing clerk named Ossava of the Ninth Recension was assigned the reconciliation of tonal records for the floors between 300 and 340, a stretch of the Tower in which the naming of floors had fallen two generations into arrears. Working late, Ossava began to hear, distinctly and at low volume, the sound of a staircase being counted — a voice reciting floor numbers in an order that matched no ascent or descent recorded in the Stairwell Register. She filed a grievance under Form A-7-T, which requires a wax-cylinder recording and a fee of one seal. The cylinder was submitted. It is blank. The grievance was nonetheless upheld on the strength of three colleagues who heard nothing but who testified that Ossava had described the sound consistently on four occasions.

The ruling, Ossava Precedent 4, established that a Tonal Residue may be certified on the testimony of its percipient alone, provided the percipient is of good standing and the description is unvarying. The Bureau of Registry has since objected that this makes every clerk a floor of their own. The Bureau's objection is noted in the margin of the ruling and nowhere else. Ossava was transferred to a quieter assignment. Ossava reports that it is not quieter.

Maintenance notes

Tonal Residue is not to be swept. The prohibition appears in the Custodial Manual for Particulate Residue as a single unnumbered line, without explanation, and custodial staff on Floors 88 through 92 have observed it without inquiry for as long as the Manual has been in use. Brooms are stored elsewhere on those floors.

Readers wishing to consult a residue directly must apply to the Sub-Shelf Reading Room and must bring their own chair; the Room's chairs are considered part of the collection.

See also

• Concordance 89
• Auditory Residue
• Perceptual Residue
• Sympathetic Residue
• “Tonal Ground,”
• Silentium Scale