HEARING AID EARMOLDS, EAR SHELLS AND COUPLING SYSTEMS

5.1 EARMOLD, EARSHELL and CANAL FITTING PHYSICAL STYLES

5.1.1 BTE earmold styles

5.1.2 ITE, ITC, and CIC earshell styles

5.2 OVERVIEW OF EARMOLD, EARSHELL AND CANAL FITTING ACOUSTICS

5.3 VENTING

5.3.1 Effects of vents on hearing aid gain and OSPL90
5.3.2 Venting and the occlusion effect
5.3.3 Effects of vents and leaks on feedback oscillations
5.3.4 Interaction of vents with signal processing algorithms
5.3.5 Parallel versus Y (or diagonal) vents
5.3.6 Open-canal fittings in summary

5.4 THE SOUND BORE: TUBING, HORNS AND CONSTRICTIONS

5.4.1 Acoustic horns and constrictions

5.4.2 Tubing insertion depth

5.5 DAMPERS

5.6 SPECIFIC TUBING, DAMPING AND VENTING CONFIGURATIONS

5.7 PROCEDURE FOR SELECTING EARMOLD AND EARSHELL ACOUSTICS

5.8 EAR IMPRESSIONS

5.8.1 Standard ear impression techniques
5.8.2 Ear impression techniques for CICs and high gain hearing aids
5.8.3 Ear impression materials

5.9 EARMOLDS AND EARSHELLS

5.9.1 Earmold and earshell construction
5.9.2 Materials for earmolds and earshells
5.9.3 Instant earmolds and hearing aids
5.9.4 Modifying and repairing earmolds and earshells

5.10 CONCLUDING COMMENTS