# Tonal components and tone adjustment (DIN 45681)

> Part of [LISQM](https://zhenxianli.github.io/LISQM/) (List of Implementations of Sound Quality Metrics), a list of open-source implementations of psychoacoustic metrics. Data as of 2026-10-28. Web page: https://zhenxianli.github.io/LISQM/metrics/tonality-din-45681.html

**Quantity:** Tonality · **Unit:** dB · **Also known as:** DIN 45681, tone adjustment, K_T, Tonzuschlag

German method that detects tonal components in noise from narrow-band spectra and derives a tone adjustment for the assessment of noise immissions. DIN 45681:2005, corrected by Berichtigung 2:2006-08 (which replaced Berichtigung 1:2005-08), is current.

The current edition is DIN 45681:2005. No open-source implementation of it has been found. Implementations of earlier editions or related models: [ITA-Toolbox](https://zhenxianli.github.io/LISQM/projects/ita-toolbox.html) (MATLAB; E DIN 45681:2002-11; maximum tonal audibility and its frequency).

## Editions and who implements them

| Date | Edition | Status | What changed | Implemented by |
|---|---|---|---|---|
| 2005-03 | [DIN 45681:2005](https://www.dinmedia.de/en/standard/din-45681/76463232) | current | Current; Berichtigung 2:2006-08 replaced Berichtigung 1:2005-08. | — |
| 2002-11 | [E DIN 45681:2002-11](https://zhenxianli.github.io/LISQM/standards.html#ref-din-45681-2002-draft) | superseded | — | [ITA-Toolbox](https://zhenxianli.github.io/LISQM/projects/ita-toolbox.html) |

## Implementations

| Project | Language | Edition | Functions | Validation (as stated) | Notes |
|---|---|---|---|---|---|
| [ITA-Toolbox](https://zhenxianli.github.io/LISQM/projects/ita-toolbox.html) | MATLAB | [E DIN 45681:2002-11](https://zhenxianli.github.io/LISQM/standards.html#ref-din-45681-2002-draft) (maximum tonal audibility and its frequency) | `ita_tonality` | not stated | The header cites "DIN 45681 (2002)", the draft that preceded DIN 45681:2005. A code comment says that no A-weighting is applied. |

**See also:** [Audibility of tones in noise (ISO/TS 20065)](https://zhenxianli.github.io/LISQM/metrics/tonal-audibility-iso-20065.html)

## How they were validated

As reported by each project; LISQM has not run the code. Two implementations that agree can still share the same error.

None of these projects says how its code was validated.

## References

1. DIN (2002). *E DIN 45681:2002-11 (draft): Akustik — Bestimmung der Tonhaltigkeit von Geräuschen und Ermittlung eines Tonzuschlages für die Beurteilung von Geräuschimmissionen*. Beuth, Berlin.
2. DIN 45681:2005. Akustik — Bestimmung der Tonhaltigkeit von Geräuschen und Ermittlung eines Tonzuschlages für die Beurteilung von Geräuschimmissionen. https://www.dinmedia.de/en/standard/din-45681/76463232