---
title: "Octave band"
description: "An octave band is a frequency range whose upper bound is twice the lower bound. Standard centre frequencies (in Hz) used for industrial-noise work are 31.5, 63, 125, 250, 500, 1000, 2000, 4000, 8000 and 16000. One-third octave bands subdivide each octave into three for higher resolution. Reporting SPL as a spectrum across these bands — instead of as a single broadband number — is the standard format for noise-exposure analysis under OSHA 29 CFR 1910.95 and EU Directive 2003/10/EC."
canonical_url: "https://sylio.co/glossary/octave-band"
last_updated: "2026-06-28T02:29:22.245Z"
---

An **octave band** is a frequency range whose upper bound is twice the lower bound. Standard centre frequencies (in Hz) used for industrial-noise work are 31.5, 63, 125, 250, 500, 1000, 2000, 4000, 8000 and 16000. **One-third octave bands** subdivide each octave into three for higher resolution. Reporting SPL as a spectrum across these bands — instead of as a single broadband number — is the standard format for noise-exposure analysis under [OSHA 29 CFR 1910.95](/glossary/osha-29-cfr-1910-95) and [EU Directive 2003/10/EC](/glossary/eu-directive-2003-10-ec).

## Why octave-band data matters for sonic horns

A 75 Hz [sonic horn](/glossary/sonic-horn) puts most of its energy into the 63 Hz octave band, with smaller amounts in adjacent bands from harmonic content. Exposure assessments at the operator station — and the design of any [sound-attenuation enclosure](/glossary/sound-attenuation-enclosure-sonic-horn) — depend on knowing the spectrum, not just the broadband SPL. Hearing-protection rating (NRR / SNR) is also octave-band-dependent.

## Related terms

- [Frequency](/glossary/frequency)
- [Decibel](/glossary/decibel)
- [Sound pressure level](/glossary/sound-pressure-level)
- [OSHA 29 CFR 1910.95](/glossary/osha-29-cfr-1910-95)
- [EU Directive 2003/10/EC](/glossary/eu-directive-2003-10-ec)