Technical bulletins

Number Title Description Downloads
TB-03 Effects of sound inlet variations on microphone response

The impact of various sound inlet tubing is discussed, including tubing diameter, length, and acoustic resistance impact on microphone reponse peak frequency, high frequency sensitivity, and overall microphone sensitivity.

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(556.85 kB)

TB-04 Soldering transducer leads

Recommended procedures and process parameters for prepping and soldering to Knowles Electronics transducers. Details on terminal construction, external leads, soldering iron, solder, flux, fixtures, and tools physical requirements are presented along with lead soldering and lead removal methods.

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(1.08 MB)

TB-05 Walk induced head vibrations and hearing aid design

Review of various sources of human body movement induced vibration that impact hearing aid performance, including "head thumps", "walk acceleration", and other physical motions that hearing aids interpret as spurious acoustic signals.

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(608.74 kB)

TB-08 Microphone and Balanced Armature Receiver Handling and Environmental Guidelines

Protocols for transducer handling, holding fixtures, soldering, contaminants, ESD, temperature, humidity, radiation, and pressure changes are listed. Also, application guidelines and recommendations for shock and vibration, contaminants, ESD, temperature, humidity, radiation, and pressure are detailed.

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(114.00 kB)

TB-19 Vibration sensitivity of Knowles microphones

Vibrations to Knowles microphones is interpretted as spurious acoustic signals. The vibration sensitivities and vibration induced acoustic responses for the BT, EA, EK, EG, and EM microphones are presented.

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(121.00 kB)

TB-23 Mounting application notes

General transducer physical mounting suggestions for antishock mounting, soldering, and acoustic transmission are reviewed.

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(228.26 kB)

TB-24 ESD and low frequency voltage noise related issues to the Improved EM microphone

The impact of electrostatic discharge (ESD) on Improved EM series microphones. Specific recommendations for microhpone handling, ESD protection, and manufacturing facility grounding are given. Also discussed is the low-frequency oscillation produced by the Improved EM microphones internal FET impedance converter circuitry.

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(105.11 kB)

TB-25 Improved EM microphone

Features and benefits of the Improved EM microphone series including sensitivity improvements, equivalent noise pressure (ENP noise), one-third octave noise, and power supply feedthrough attenuation (PFA) are each examined in detail.

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(290.99 kB)