免费倍频程频率计算器
计算倍频程和1/3倍频程中心频率和带宽。
Lower Band Edge
707.1068 Hz
Lower Band Edge vs Centre Frequency
公式
## 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.
计算示例
1000 Hz full octave band.
- 01f_upper = 1000 * 2^(1/2) = 1000 * 1.4142 = 1414.2 Hz
- 02f_lower = 1000 / 2^(1/2) = 1000 / 1.4142 = 707.1 Hz
- 03Bandwidth = 1414.2 - 707.1 = 707.1 Hz
常见问题
Why use octave bands instead of equal-width bands?
Our hearing perceives pitch logarithmically. Octave bands have constant percentage bandwidth, matching how we hear. Each band sounds equally wide.
What are the standard octave band centre frequencies?
31.5, 63, 125, 250, 500, 1000, 2000, 4000, 8000, and 16000 Hz. These are preferred frequencies defined in ISO standards.
Why are third-octave bands used?
They provide finer frequency resolution while maintaining the constant-percentage-bandwidth advantage. They are standard for building acoustics and noise regulations.
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