Every figure on this register carries its unit, its weighting or window, and its source; a number without those three is not published here.
Method: how this register derives its acoustic figures
checked 2026-09-16responsible Room Tone Register (a named register, not a person)
Where the figures come from
Every number on this register is one of three things: a level in dB SPL with its weighting and averaging stated, a time in seconds with its measurement window stated, or a coefficient with its test method stated. A figure missing any of those is not used here. That is the whole method.
Units and the traps that go with them
| Quantity | Unit | The trap |
|---|---|---|
| Level | dB SPL, A-weighted | A and C differ most below 100 Hz; a reading without its weighting is meaningless |
| Averaging | slow, or Leq over a stated window | fast averaging reads high on a fluctuating source |
| Reverberation time | seconds, per octave band | a single broadband figure hides the bass |
| Absorption coefficient | dimensionless, 0–1, per band | NRC averages four mid bands and says nothing at 125 Hz |
| Distance | metres | level falls 6 dB per doubling; the room does not |
How sources are chosen
A source is used only if it is a specific document that supports a specific sentence on the page, and only if it can be opened. University course material, standards bodies and safety agencies are preferred because they publish their methods. Vendor material is used only where the vendor is describing its own measurement practice, and never for a comparative claim.
What is measured here and what is not
The register measures rooms, not products. It does not rank microphones, panels or meters, and it does not accept advertising. Where a page quotes a manufacturer's figure it says so and names the document. Where a page quotes a measurement taken by this register it gives the conditions: position, weighting, averaging and duration.
The register's own measurements in the notes are single-room observations. They are published because the method is stated and can be repeated, not because they generalise to every room.
Source log
- 01AES standards (Audio Engineering Society)supports the standards framework this register's units follow
- 02What is self-noise or equivalent noise level (Neumann)supports the self-noise specification that a microphone figure has to be read against
- 03Scattering of Sound, Penn State Acousticssupports the scattering behaviour that makes a room's response position-dependent
Each line points at one specific document. No line is a home page.
Leave this page Close this page once you know which unit a figure is in. The rest of the register assumes that.