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An octave band is a frequency band that spans one octave (Play ⓘ).In this context an octave can be a factor of 2 [1] [full citation needed] or a factor of 10 0.301. [2] [full citation needed] [3] [full citation needed] An octave of 1200 cents in musical pitch (a logarithmic unit) corresponds to a frequency ratio of 2 / 1 ≈ 10 0.301.
For example, the frequency one octave above 40 Hz is 80 Hz. The term is derived from the Western musical scale where an octave is a doubling in frequency. [note 1] Specification in terms of octaves is therefore common in audio electronics. Along with the decade, it is a unit used to describe frequency bands or frequency ratios. [1] [2]
Speech Transmission Index (STI) is a measure of speech transmission quality. The absolute measurement of speech intelligibility is a complex science. The STI measures some physical characteristics of a transmission channel (a room, electro-acoustic equipment, telephone line, etc.), and expresses the ability of the channel to carry across the characteristics of a speech signal.
Note that roll-off can occur with decreasing frequency as well as increasing frequency, depending on the bandform of the filter being considered: for instance a low-pass filter will roll-off with increasing frequency, but a high-pass filter or the lower stopband of a band-pass filter will roll-off with decreasing frequency. For brevity, this ...
It is used to characterize a noise signal in the frequency range where the human ear has its highest sensitivity. The Speech Interference Level is calculated as the arithmetic mean of unweighted sound pressure levels in three or four octave bands in the 500 Hz - 4 kHz frequency range Several variants of the Speech Interference Level are in use:
The noise reduction coefficient is "a single-number rating, rounded to the nearest 0.05, of the sound absorption coefficients of a material for the four one-third octave bands at 250 Hz, 500 Hz, 1000 Hz and 2000 Hz". [4]
Tone control is a type of equalization used to make specific pitches or frequencies in an audio signal softer or louder. It allows a listener to adjust the tone of the sound produced by an audio system to their liking, for example to compensate for inadequate bass response of loudspeakers or earphones, tonal qualities of the room, or hearing impairment.
Magnitude response of a low pass filter with 6 dB per octave or 20 dB per decade roll-off. Measuring the frequency response typically involves exciting the system with an input signal and measuring the resulting output signal, calculating the frequency spectra of the two signals (for example, using the fast Fourier transform for discrete signals), and comparing the spectra to isolate the ...