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Figures for Chapter 1 Introductory concepts. Dillon (2001) Hearing Aids. Audibility of formants. First formant. Second formant. oo. Sound level. ee. 250. 500. 1000. 2000. 4000. Frequency (Hz).
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Figures for Chapter 1Introductory concepts Dillon (2001) Hearing Aids
Audibility of formants First formant Second formant oo Sound level ee 250 500 1000 2000 4000 Frequency (Hz) Figure 1.1 Similarity of the two vowels oo and ee when the second formant is inaudible because of hearing loss (grey area). Source: Dillon (2001): Hearing Aids
Reduced dynamic range Too loud Too soft Too loud Too loud Intense Intense Moderate (b) (c) Moderate Weak Weak Too soft Too soft Intense Moderate Weak (a) Norm Sam Figure 1.2 The relationship between the dynamic range of sounds in the environment and the dynamic range of hearing for: (a) normal hearing, (b) sensorineural hearing loss without amplification, and (c) sensorineural hearing loss with a constant amount of amplification for all input levels. Source: Dillon (2001): Hearing Aids
Reduced spectral resolution (a) Sound level 250 1000 4000 (b) Excitation Frequency (Hz) 250 1000 4000 Figure 1.3 (a) Sound spectrum, and (b) representation in the auditory system for normal hearing (dotted line) and sensorineural hearing impairment (solid line). Source: Dillon (2001): Hearing Aids
Figure 1.4 Input-output diagram for a hearing aid with 20 dB gain, showing how the output SPL depends on the input SPL, for a particular signal or frequency. Source: Dillon (2001): Hearing Aids I-O diagram
Figure 1.5 Gain-frequency response of an in-the-ear hearing aid at maximum volume control position (solid line) and reduced volume control position (broken line). Gain-frequency response Source: Dillon (2001): Hearing Aids
Figure 1.6 Saturated sound pressure level frequency response of an in-the-ear hearing aid. Source: Dillon (2001): Hearing Aids SSPL or OSPL90
Photo has been removed to minimize file size. Figure 1.7 A BTE hearing aid. Source: Dillon (2001): Hearing Aids
Photo has been removed to minimize file size. Figure 1.8 An ITE, an ITC and a CIC hearing aid. Source: Dillon (2001): Hearing Aids
Microphone Volume control Receiver Battery Fitter control Vent Microphone Volume control Fitter controls Receiver Switch Amplifier Ear-hook Battery Component location Figure 1.9 The typical location of components in an ITC and a BTE hearing aid. Source: Dillon (2001): Hearing Aids
Spectacle aids Photo has been removed to minimize file size. Figure1.10 Spectacle adapter system showing two different adapters and BTE hearing aids, an earmold, and a spectacle bow. The bow would be cut at the white line and the left half inserted in the adapter.
Acoustic hearing aids Figure 1.11 Three acoustic era instruments: (a) The Auricle, (b) the horn, and (c) the speaking tube. Photo has been removed to minimize file size.
Carbon aid Photo has been removed to minimize file size. Figure 1.12 A carbon aid (The Acousticon) without its battery.
Vacuum-tube aid Photo has been removed to minimize file size. Figure 1.13 A relatively late vacuum tube hearing aid, with its two separate batteries. Source: Dillon (2001): Hearing Aids