Before revision: It specifies that "the talker should be seated in a quiet room with volume between 30 and 120 dB and a reverberation time less than 500 ms (preferably in the range 200–300 ms).
After revision: It specifies that "the talker should be seated in a quiet room with volume between 30 and 120 m and a reverberation time less than 500 ms (preferably in the range 200–300 ms).