Technical bulletins

Number Title Description Downloads
TB-02 Receiver Testing: Maximum current modulation (MCM)

Testing of DC-biased receivers for receiver response and distortion under real-life scenarios using a more accurate test method

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(502.25 kB)

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-06 Effects of acoustical termination upon receiver response

External tubing can greatly impact a receivers response curve. Varying the tubing length, varying the tubing diameter, using combinations of different tubing lengths/diameter, and adding acoustic dampers can all have a marked impact on receiver output.

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(413.30 kB)

TB-07 Effects of source impedance upon receiver response

The impedance of the signal source with respect to the receiver's impedance can affect the shape of the response curve. The impact of source impedance vs. receiver impedance matching is presented for constant current, constant voltage, and maximum available power drives.

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(206.17 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-09 BT condenser microphone 2-wire application notes

Design guides and application notes for using the BT microphone with 2-wire driver/pre-amp circuitry. Numerous sample circuits and examples are presented.

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(304.92 kB)

TB-11 Effectrs of variation of supply voltage on the sensitivity of the BL microphone

The impact on BL microphone sensitivity by using supply voltages from 0.9VDC to 20.0VDC is discussed.

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(137.74 kB)

TB-12 Application notes for BL series microphones

General design guidelines and application suggestions for the BL series microphones including 3-wire and 2-wire pre-amp/driver circuits and the reduction of power supply ripple voltage.

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(158.10 kB)

TB-13 Effects of variation of the supply voltage on the sensitivity of the BT microphone

The impact on BT microphone sensitivity by using supply voltages in the 0.4VDC to 1.3VDC range and the 1.3VDC to 20.0VDC range are discussed.

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(121.60 kB)

TB-14 The effect of acoustic damping plugs on receiver response

Use of the BF series dampers to smooth receiver response curve resonance peaks for CI, EF, ED, and EH series receivers. Impact of various amounts of acoustic resistance, difference damper styles, different damper diameters, and different damper positioning is examined via numerous examples.

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(423.93 kB)

TB-16 Electronics response shaping of directional microphones

The use of analog RC filter networks to shape the low-frequency and high-frequency responses of Knowles directional microphones. Also includes implementation suggestions on the equalization of Knowles microphones in directional applications.

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(182.96 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-20 Wideband receiver application bulletin

Several examples of extending the ED and BP receiver frequency response via different acoustic tubing constructions are reviewed. Included are physical devices layouts and frequency response comparison curves.

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(208.25 kB)

TB-21 Application of EL Directional Microphones

Guidelines for selection and use of the EL series directional microphones

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(263.20 kB)

TB-22 Magnetic leakage for receivers

Examination of magnetic radiation (mag rad) phenomina for BK, BP, ED, and EF series receivers. Mag rad field amplitude, field orientation, and critical frequencies are discussed.

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(182.75 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-26 The Use of BU Series Accelerometers

Application and use of BU series accelerometers for bone-conduction voice pickup, vibration detection, and industrial monitoring

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(637.68 kB)