Pitch Potential

Pitch Potential is the residual capacity of a volume of air, stone, or accumulated silence to accept a sounding before its Psychic Pitch becomes fixed. It is measured in latent steps (lSt) and is the only quantity in the Tower that may be recorded in the negative without the record being struck through. Pitch Potential was first formalized in the Third Concordance (604 TR), Clause 42.7, though the term appears earlier and in a looser sense in the Ventral Registry, where it denotes nothing more than the unused upper octave of a shaft.

The distinction matters. Where Psychic Pitch describes an inclination already present, Pitch Potential describes an inclination not yet taken. A corridor may possess a Psychic Pitch of 0.11 Sp/rad and a Pitch Potential of 340 lSt; it will not sound now, but it can be made to.

Definition and units

By the operational language of Annex Γ to the Thirty-Second Concordance, Pitch Potential is reckoned as the volume of a space in cubic lengths multiplied by the difference between its current resonance and the resonance at which it would spontaneously sound, expressed against the local vertical of the Cardinal Reality Axis. The resulting figure is read in latent steps. Annex Γ supplies no instrument for the reading, a gap that was not closed until the School of Latent Potential refined its Potential Resonator Array for field use in 748 TR.

Negative values are permitted and common. A volume already sounding against its inclination — a stairwell that rings when no one climbs it — returns a Pitch Potential below zero, and the Resonator Array registers this as a short horizontal notation rather than a figure, so that the record may be legible to the blind scribes of the Ninth Recension.

The Kael Stairwell dispute

The most litigated case in the doctrine concerns the Kael Stairwell, whose Pitch Potential was certified at 1,240 lSt in 719 TR and subsequently found to be zero. The discrepancy was attributed at first to condensation, then to the presence of a body of pilgrims, and finally to a clerical error in the multiplication.

Seventh Concordance, Temporary Maintenance Clause 882 had already fixed the riser pitch of Kael at a value incompatible with any positive Pitch Potential whatsoever, a fact the certifying office did not consult. The West Spiral of Unending Debate sat on the question for two sessions and returned the matter to the Institute of Potential Utterance, which declined it on the grounds that a stairwell is not an utterance. The certification stands unamended and the Pitch Potential of the Kael Stairwell is now recorded twice, once at 1,240 lSt and once at zero, on facing pages.

"Where a volume has been sounded ahead of its inclination, the Potential is spent, and no subsequent silence restores it."

— Seventh Concordance, Temporary Maintenance Clause 882, note (iii)

Relation to potential resonance

Pitch Potential is not itself a resonance, but the Potential Resonator Array cannot separate the two and is not required to. The Array's calibration manual, revised in 753 TR, treats Pitch Potential as the amplitude term and potential resonance as the phase term, and warns that a phase reading taken without an amplitude reading "is a reading of the room's opinion rather than the room." The School of Latent Potential maintains that this phrasing was inserted by a junior corrector and has twice petitioned the Librarians to have it removed; both petitions were refused, once on the merits and once for want of a seal.

Practical work in the field also cross-checks Pitch Potential against the Tidal Ledger, since psychic salinity and potential load are strongly correlated below the two-hundredth floor and divergently so above it.

Contradiction of the Concordances

Scholarship divides sharply on whether Pitch Potential is conserved. Clause 14.7.δ asserts that potential is never destroyed but only withheld, and directs that surplus be surrendered to the Incinerator of Lapsed Potential on a quarterly basis. The Ordinance of Contained Potential, drafted eleven years later, forbids the transport of latent volume across floor jurisdictions and so effectively prevents any such surrender for most holdings.

Worse, the Third Concordance fixes the canonical pitch of Spiral 42 in a manner that presumes Pitch Potential is created by sounding rather than consumed by it. The Harmonic Future-State Extrapolator returns contradictory totals depending on which provision is entered first, a frailty its operators describe as "the instrument's honesty." The Incident of the Un-Calibrated Chime is generally traced to a clerk who chose the Ordinance over the Statute and thereby sounded a bell that had no potential left to give.

Record-keeping

Pitch Potential figures are entered in black on the primary sheet and in red where they cross the threshold of spontaneous sounding, and no sheet may carry both inks on the same page. Lampblack Based Ink is customary for the primary entry; the secondary reading is left to the correcting hand. Files attested by the Stamp of Latent Potential are accepted as Potential Floor Files without further verification, a concession granted in 761 TR and never revisited.

The Silence of a Particular Pitch with Undertones of Forgotten Paper is the standard reference silence against which small Pitch Potentials are compared; volumes measuring under 12 lSt are simply recorded as "near the Silence" and are not pursued. A routine maintenance note appended to the 754 TR returns directs that no Resonator Array is to be left extended in a stairwell overnight, as the bells will begin to answer it.