Articulation Testing by Bone Conduction
Norman A. Watson · The Journal of the Acoustical Society of America · 1936
The paper describes briefly the apparatus used for transmitting the recorded articulation lists to the bone-conduction vibrator, and the construction of the induction type electrodynamic vibrator itself. Results of articulation tests on normal-hearing persons are given which indicate that, with high quality apparatus and sufficient power, articulations can be obtained by bone conduction as high as those by air conduction. 100 percent often being attained. The variation of percent syllable articulation with increasing level is given for bone conduction for open ear canals and for partially blocked canals. The effects of the following factors on percent syllable articulation are also discussed: (1) Variation of total force and pressure of the vibrator against the observer's head; (2) frequency and nonlinear distortion in the amplifier system; (3) use of multiple vibrators; and (4) clenching of teeth and other variations of the condition of the observer's head.