Calculateur de DB par octave

Le dB Per Octave Calculator helps users determine the rate of gain or atténuation over frequency changes in audio engineering, electronics, and signal processing.

An octave represents a doubling (or halving) of frequency, so this calculator is useful for:

• Égalisation audio – Adjusting speaker and filter responses
• Loudspeaker design – Understanding high-frequency roll-off
• Filter slopes – Measuring attenuation in low-pass and high-pass filters
• Room acoustics and sound analysis – Evaluating how frequencies change across different environments

By using this tool, audio engineers, sound designers, and RF technicians vous optimize frequency response and improve system performance.

Formula for Db Per Octave Calculator

La formule pour calculer dB per octave est:

Formule générale

dB per Octave = (dB Change) / (log2(Freq2 / Freq1))

Où :

• dB Change = Gain or loss in decibels between two frequencies
• Freq1, Freq2 = The two frequencies where des mesures ont été prises
• Log2 = Base-2 logarithm (since an octave represents a doubling of frequency)

Simplified Formula (for 1-Octave Differences)

Depuis un an octave means the frequency doubles (Freq2 = 2 × Freq1), l'équation se simplifie comme suit :

dB per Octave = dB Change / Number of Octaves

This means if a system experiences -6 dB attenuation plus de une octave, il est slope is -6 dB per octave.

Reference Table – Common dB Per Octave Slopes

To make frequency response estimation easier, here is a table de référence de commun filter slopes and signal attenuation rates:

Type de filtre	dB per Octave	Application
First-Order Filter	-6 dB/octave	Simple tone control, basic crossover design
Second-Order Filter	-12 dB/octave	Active crossovers, equalization circuits
Third-Order Filter	-18 dB/octave	Steeper filtering for precise frequency control
Fourth-Order Filter	-24 dB/octave	High-precision filtering in audio and RF circuits
Atténuation acoustique	-3 dB/octave	Air absorption of high-frequency sounds

Ce tableau aide audio professionals and engineers comprendre how signals change per octave and how steep a filter or system response will be.

Example of Db Per Octave Calculator

1. Calculate dB Per Octave for a Sound System

A speaker system has a -12 dB loss jusqu'à XNUMX fois 500 Hz et 2000 Hz.

1. Find the number of octaves:
   Octaves = log2(2000 / 500)
   Octaves = log2(4) = 2 octaves
2. Appliquez la formule :
   dB per Octave = (-12 dB) / (2 octaves)
   dB per Octave = -6 dB par octave

This means the system attenuates by 6 dB for every frequency doubling.

2. Calculate dB Per Octave for a High-Pass Filter

A low-frequency signal passe par -18 DB jusqu'à XNUMX fois 250 Hz et 1000 Hz.

1. Find the number of octaves:
   Octaves = log2(1000 / 250)
   Octaves = log2(4) = 2 octaves
2. Appliquez la formule :
   dB per Octave = (-18 dB) / (2 octaves)
   dB per Octave = -9 dB par octave

This suggests the filter roll-off is steeper than a second-order filter (-12 dB/octave), making it closer to a third-order filter (-18 dB/octave).

FAQ les plus courantes