Speech Terms, Definitions, Units, Measurements ...
Speech the ability to express thoughts and feelings by articulate sounds. We have listed the common acoustical terms alphabetically on this page and links to other relevant terms
● Note 1 : the word articulation is used when the units of speech material are meaningless syllables or fragments; the word intelligibility is used when the units of speech material are complete, meaningful words, phrases or sentences
● Note 2 : it is important to specify the type of speech material: phonemes, logatomes, syllables, words, sentences, etc. The kind of speech material used is identified by an appropriate adjective syllable articulation, vowel (or consonant) articulation, monosyllabic word intelligibility, discrete word intelligibility, sentence intelligibility.
Articulation is also known as intelligibility
See also • haas effect • music clarity • speech clarity
Intelligibillity see • articulation • speech intelligibility
C80 is a guide to music clarity and is a measure of the ratio of the sound energy arriving during the first 80 milliseconds and the sound energy arriving after 80 ms.
C80 = 10·Log ((Energy(0-80ms)/(Energy(80ms-end)) dB
See also • haas effect • speech clarity
● Note : although SIL, SIL3 and the PSIL Preferred Speech Interference Level are defined for octave band levels they are also calculated from the 1/3-octave bands within each octave before doing the average.
See also • speech interference level.
See also • speech transmission index
This system is considered by some to more effective than the noise criteria (NC) system.
The B&K 2250 sound analyser, measures room criteria values.C50 guide to speech clarity and is a measure of the ratio of the sound energy arriving during the first 50 milliseconds and the sound energy arriving after 50 ms.
C50 = 10·Log ((Energy(0-50ms)/(Energy(50-end)) dB
See also • haas effect • music clarity
CIS : common intelligibility scale
RASTI : rapid speech transmission index
STI : speech transmission index
STIPA : speech transmission index for public address systems
STITEL : speech transmission index for telecommunication systems
See also • threshold of speech intelligibility and the articulation
● Note 1 : the word articulation is used when the units of speech material are meaningless syllables or fragments; the word intelligibility is used when the units of speech material are complete, meaningful words, phrases or sentences
● Note 2 : it is important to specify the type of speech material: phonemes, logatomes, syllables, words, sentences, etc. The kind of speech material used is identified by an appropriate adjective syllable articulation, vowel (or consonant) articulation, monosyllabic word intelligibility, discrete word intelligibility, sentence intelligibility.
Intelligibility is also known as articulation
See also • preferred speech interference level
Speech Power • average speech power • instantaneous speech power • peak speech power
See also speech transmission index or our PDF file on speech privacy
PI = 0 indicates a complete lack of privacy
PI = 100 means complete privacy
See also speech intelligibility
See also • speech intelligibility and the articulation definition : IEC 801-29-45