Octave 1/1 Band

OCTAVE 1/1BAND

Introduction

The word ‘octave’ is derived from the Latin word meaning ‘eight’. In the musical world where there are 7 notes, the 8^th note sounds twice as high as the 1^st note. The 8^th note is an octave higher than the 1^st note. Similarly in the octave band, the upper limit frequency is twice the lower limit frequency. Octave bands are very useful in engineering applications because they reveal the spectral content, meaning they represent the change in noise levels with respect to the frequency of sound. This helps in identifying which frequency is responsible for the noise which helps in nailing down the component in a machine responsible for the frequency.

Octave 1/1 Band

Equations

The relation between the next and the previous center frequency is given by,

n = 1 for 1/1octave band

C_F – center frequency

C_Fnext – next center frequency

C_Fprev – previous center frequency

Upper and lower band frequency limits:

The relation between the upper band and lower band frequency limit for a given frequency band is given by,

C_L – lower band limit for a given center frequency

C_U – upper band limit for a given center frequency

Tabular column

Frequencies bands in the entire range, upper & lower band limits

Octave 1/3 band	Center frequency	Lower band limit	Upper band limit
	Hz	Hz	Hz
Band1	16	11	22.1
Band2	31.5	22.1	44.2
Band3	63	44.2	88.4
Band4	125	88.4	176.8
Band5	250	176.8	353.6
Band6	500	353.6	707.1
Band7	1000	707.1	1414.2
Band8	2000	1414.2	2828.4
Band9	4000	2828.4	5656.9
Band10	8000	5656.9	11313.7
Band11	16000	11313.7	22627.4

Octave 1/1 Band Real Time Analysis