Handbook for Sound Engineers

Acoustics for Auditoriums and Concert Halls 157

basis of the word-frequency dictionary and a
language-relevant phoneme distribution. In German
intelligibility test logatoms (monosyllable conso-
nant-vowel-groups that do not readily make sense, so
that a logical supplementation of logatoms that were not
clearly understood during the test is not possible—e.g.,
grirk, spres) are used for exciting the room. In
English-speaking countries, however, test words as
shown in Table 7-3 are used.^19 There are between 200
and 1000 words to be used per test. The ratio between
correctly understood words (or logatoms or sentences)
and the total number read yields the word or syllable or
sentence intelligibility V rated in percentages. The intel-
ligibility of words VW and the intelligibility of sentences
VS can be derived from Fig. 7-11.

Table 7-4 shows the correlation between the intelligi-

bility values and the ratings.

Figure 7-10. Articulation loss Alcons as a function of the
level ratio between diffuse sound LR and direct-sound level
LD, reverberation time RT 60 and noise level LN.

Table 7-3. Examples of English Words Used in Intelli-

gibility Tests

aisle done jam ram tame

barb dub law ring toil

barge feed lawn rip ton

bark feet lisle rub trill

baste file live run tub

bead five loon sale vouch

beige foil loop same vow

boil fume mess shod whack

choke fuse met shop wham

chore get neat should woe

cod good need shrill woke

coil guess oil sip would

coon hews ouch skill yaw

coop hive paw soil yawn

cop hod pawn soon yes

couch hood pews soot yet

could hop poke soup zing

cow how pour spill zip

dale huge pure still

dame jack rack tale

Figure 7-11. Assessment of the quality of speech intelligi-

bility as a function of syllable intelligibility VL, word intelligi-

bility VW, and sentence intelligibility VS.

Syllable intelligibiliy VL–%

unsatifactory poor satisfactory good

excellent