Room Tone Register
1 2 3 4 5 6 air handler fridge ballast outside bodies door MIC POSITION measured spectrum at the mic position 63 125 250 500 1k 2k 4k The two tallest bars are 125 Hz and 250 Hz. That is the room's own voice. Everything below is a decision: treat it, move it, or write it on the slate.
The room in section, with the six sources that decide its tone, and the spectrum they produce. Not to scale.

Room Tone Register: measure the room before you record in it

Leave this page holding one number — the room's noise floor in dB(A) — and one decision from three options: move the microphone, treat the source, or accept the floor and write it on the slate.

Every page on this register serves one of three numbers: the noise floor, the decay time, and the mains hum. Ten objects define them. Seven jobs put them to work. Six notes record where the sources disagree.

checked 2026-09-16responsible Room Tone Register (a named register, not a person)

Terms

Procedures

Log

How the register is kept

Nothing here is a feed. The clock is a manual: objects are definitions and carry no date, numbers that rot carry a checked line, and only the notes are dated. Every page prints the formula it uses and a worked substitution with real numbers, because a figure without its arithmetic is not evidence.

Sources are deep links to specific documents, and each one states the sentence it supports. The register does not review equipment, does not sell anything, and does not write about topics it cannot measure. What it refuses is listed on the refuse page, with a reason per line.

Leave this page when you have the floor number and the three-way decision. That is the whole point of the homepage.

Source log

  1. 01ISO 3382-1 revision (ISO/CD 3382-1)supports the measurement standard the register's room figures follow
  2. 02ISO 1996-1: Description, measurement and assessment of environmental noisesupports the environmental-noise assessment framework the register borrows its weighting from
  3. 03ISO 9613-2: Attenuation of sound during propagation outdoorssupports the propagation model used when the source is outside the room

Each line points at one specific document. No line is a home page.