Octave Band Frequency Calculator — Formula
## Octave and Fractional-Octave Bands
Sound analysis often divides the spectrum into bands of constant percentage bandwidth.
### Formulas
**f_upper = f_c * 2^(1/(2N))**
**f_lower = f_c / 2^(1/(2N))**
where N is the fraction denominator (1 for full octave, 3 for third-octave).
For a full octave band (N=1): f_upper/f_lower = 2 (one octave). For third-octave (N=3): the ratio is 2^(1/3) = 1.26.
Sound analysis often divides the spectrum into bands of constant percentage bandwidth.
### Formulas
**f_upper = f_c * 2^(1/(2N))**
**f_lower = f_c / 2^(1/(2N))**
where N is the fraction denominator (1 for full octave, 3 for third-octave).
For a full octave band (N=1): f_upper/f_lower = 2 (one octave). For third-octave (N=3): the ratio is 2^(1/3) = 1.26.
Exemplo Resolvido
1000 Hz full octave band.
- f_upper = 1000 * 2^(1/2) = 1000 * 1.4142 = 1414.2 Hz
- f_lower = 1000 / 2^(1/2) = 1000 / 1.4142 = 707.1 Hz
- Bandwidth = 1414.2 - 707.1 = 707.1 Hz