| Kreul EJ (5) |
Each vowel sound was demonstrated to the subjects, and they were urged, through standardized instructions and example, to sustain each vowel sound just as long as possible. All vowel productions were monitored for correctness and all efforts were recorded to the nearest half second. |
No |
| Ptacek and Sander (12) |
Pitches were specified for participants as follows: 130 Hz for males and 210 Hz for females. Whenever necessary, playback of the vowel /a/ sustained at the correct frequency was fed into the earphone worn by the subject to assist him in his frequency monitoring. Sound pressure level (re 0.0002 dyne/cm ˆ2), monitored by a VU meter, was 82 dB (+/- 4 dB), with a mouth-to-microphone distance of two inches. |
Yes |
| Mueller PB (13) |
A microphone “VISI-PITCH 6087A” was used to ensure consistency of pitch and loudness levels in intrasubject trials. The author excluded participant data in which the variability between trials was greater than 10 Hz. |
Yes |
