AN-1: Transducer Signal Port Location Key
Provides key to Knowles' port location and terminal location naming system for all microphones and receivers. Numerous examples of various port locations are provided.
Download Application Note AN-1 (Issue 03, PDF format, 40kB)

AN-2: Direct mounting considerations for FG series cylindrical microphone
Mounting guidelines for attaching the FG microphone directly to the hearing aid faceplate. Also provides vibration sensitivity comparison of FG microphone versus other Knowles microphones.
Download Application Note AN-2 (Issue 03, PDF format, 78kB)

AN-3: The measurement and suppression of RF interference from TDMA phones
How can cellular phones or other RF signals interfere with microphone and hearing aid operation? Examines various telecommunications protocols (TDMA, CDMA, GSM, USDC, DECT) and various frequencies (900MHz, 1.8GHz, 2.4GHz) impact on microphone performance and discusses how EMI gets into the signal path. Presents solutions on reducing RFI and EMI by using Knowles "C" and "CX" microphone technology.
Download Application Note AN-3 (Issue 03, PDF format, 107kB)

AN-4: Directional microphone applications
Overview of directional microphones for hearing aids. Examines different microphone polar responses (omnidirectional, cardioid, supercardioid, hypercardioid) and there uses and impact on hearing aid directivity. Includes design discussion of AI-DI (articulation index weighted directivity index) and real-world applications including KEMAR and in-situ measurements.
Download Application Note AN-4 (Issue 01, PDF format, 238kB)

AN-6: Ferrofluid damped ED receivers
Application and designers' guide to using ferrofluid damped receivers. Discusses damping level for current drive (CI) and voltage drive (CV) applications, damping options, ITE aid and BTE aid frequency reponse, temperature performance, improved shock performance, distortion performance, and multiple damping techniques (Type I screen damping, Type II damping, Type III multipierce diaphragm damping, and ferrofluid damping)
Download Application Note AN-6 (Issue 01, PDF format, 511kB)

AN-7: Ferrofluid damped receiver part numbering system
Details the part numbering nomenclature used for specifying ferrofluid receivers, including series definition, based model numbers, the specific -i02, -i04, and -i06 suffices used for calling out the amount of ferrofluid damping, and laser marking used on the receivers themselves. Numerous examples of complete model numbers and laser markings are included
Download Application Note AN-7 (Issue 02, PDF format, 90kB)

AN-8: HC series high-output receivers
Application and designers' guide to understanding and using the HC series High-Output receiver. Covers design basis, comparies HC series performance to FC receivers, ED receivers, and Microtronic 2600 receivers for nominal response, maximum power output (MPO), efficiency, distortion, and square wave repsonses. Details acoustic tubing, coil impedance, and damping impacts of HC receiver response and performance.
Download Application Note AN-8 (Issue 01, PDF format, 171kB)

AN-9: Thin Mic family microphones
Examines performance aspects and applications for the Thin Mic family including the TO Thin Omni, TD Thin Directional, and TP Thin Pair microphones. Front-volume and rear-volume mutual loading impact on frequency response and directionality is exaimined along with mounting considerations and external tubing needs for maximizing directivity.
Download Application Note AN-9 (Issue 01, PDF format, 872kB)

AN-10: Transducer warranty date code numbering system
Knowles Electronics system nominclature for laser-marking manufacturing dates codes with week and year of manufacture, location of manufacture, and warranty period is detailed. Warranty extension markings are reviewed along with numerous examples of date code markings.
Download Application Note AN-10 (Issue 01, PDF format, 23kB)

AN-11: VEF Vibration Isolation receivers
The can-within-a-can design of the VEF receiver is examined along with specific mounting suggestions for minimizing vibration response. Design theory and test measurement systems are reviewed along with performance aspects of the VEF's rubber suspension systems. Specifc application guides for magnetic radiation (mag rad) reduction, coil changes, damping changes, terminal pad location, and port location are given.
Download Application Note AN-11 (Issue 01, PDF format, 153kB)

AN-13: Lead-Free Soldering to Hearing Aid Transducers
Download Application Note AN-13 (Issue 01, PDF format, 1846kB)

AN-14: Marking of Microphone Pairs
Download Application Note AN-14 (Issue 01, PDF format, 124kB)

AN-16: A Passive Current Source for Two-Wire Microphones
Download Application Note AN-16 (Issue 01, PDF format, 152kB)