DFG-30445-000

DFG-30445-000 Datasheet

DFG Directional Microphone

Part	Datasheet
DFG-30445-000	DFG-30445-000 (pdf)

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  Application Note DFG Directional Microphone Background DFG Patent Pending is a new directional microphone series based on the FG series. The DFG front sound port is on the surface opposite the terminal pads same as for the FG series. The rear sound port is composed of a plurality of slots along the diameter halfway along the side. Front Sound Port Terminal Pads Rear Sound Ports DFG is currently available in three models: Model Polar Pattern Cardioid Comment Internal delay external delay Internal delay < external delay Internal delay << external delay The directional performance listed above assumes the microphone is measured without a fixture or any additional housing or packaging. The external delay is the time for sound to travel from the front sound port to the rear sound ports. The internal delay depends on the construction of the microphone element. The three available models have differing internal delays. AMERICAS Knowles Acoustics 1151 Maplewood Drive Itasca, IL 60143 U.S.A. Phone 630-250-5930 Fax 630-250-5932 EUROPE Knowles Acoustics York Road, Burgess Hill West Sussex, RH15 9TT England Phone +44-1444-235432 Fax +44-1444-872772 JAPAN Knowles Electronics Japan, KK 2-2-16, Sangenjaya, Setagaya-ku, Tokyo 154-0024 JAPAN Tel. +81-3-5779-8503 Fax +81-3-5779-8523 1 of 9 ASIA Knowles Acoustics 5F, No. 129, Lane 235, Bauchiau Rd. Shindian City, Taipei 231, Taiwan Republic of China Phone 886-2-8919-1799 Fax 886-2-8919-1798   Construction All three DFG models have the same external construction. Application Note The height of DFG is slightly greater than FG due to the added thickness of the center plate. Performance The directional performance of DFG is 100% tested in production. For practical reasons, the production test uses a holding fixture that makes contact with the microphone terminals. The fixture slightly increases the external delay for the measurement. The measurement is made in a sound box to facilitate loading and unloading. The production test condition is described on Sheet of the model specification. Sheet of the model specification shows typical near field performance and directional performance in an anechoic chamber without a test fixture. Typical near field response is measured with the microphone 6mm above the aperture of a B&K Type 4227 Mouth simulator. Typical far field and polar performance is measured 1m from the sound source in an anechoic chamber. Typical Polar Performance is measured at 125Hz, 1kHz, 4kHz, and 10kHz. Placing the microphone element in a housing will typically increase the distance between the front and rear port, which will make a cardioid pattern look more like a supercardioid pattern, and increase near field sensitivity. Port Spacing AMERICAS Knowles Acoustics 1151 Maplewood Drive Itasca, IL 60143 U.S.A. Phone 630-250-5930 Fax 630-250-5932 EUROPE Knowles Acoustics York Road, Burgess Hill West Sussex, RH15 9TT England Phone +44-1444-235432 Fax +44-1444-872772 JAPAN Knowles Electronics Japan, KK 2-2-16, Sangenjaya, Setagaya-ku, Tokyo 154-0024 JAPAN Tel. +81-3-5779-8503 Fax +81-3-5779-8523 2 of 9 ASIA Knowles Acoustics 5F, No. 129, Lane 235, Bauchiau Rd. Shindian City, Taipei 231, Taiwan Republic of China Phone 886-2-8919-1799 Fax 886-2-8919-1798    Application Note typical performance The 1kHz polar pattern for measured at 1m in an anechoic chamber is approximately cardioid. The polar curves below represent actual data from a typical microphone output amplitude in dB relative to 0 degrees . Zero degrees 180 degrees The typical frequency response curves are based on the average performance of several microphones. For a near field application such as a headset, the designer may wish to add a filter to the microphone output to flatten the rising response at high frequencies. For measurement, the microphone was suspended on lead wires for the typical tests as shown.

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 

Application Note

DFG Directional Microphone

Background DFG Patent Pending is a new directional microphone series based on the FG series. The DFG front sound port is on the surface opposite the terminal pads same as for the FG series. The rear sound port is composed of a plurality of slots along the diameter halfway along the side.

Front Sound Port

Terminal Pads

Rear Sound Ports

DFG is currently available in three models:

Model

Polar Pattern

Cardioid

Comment

Internal delay external delay Internal delay < external delay Internal delay << external delay

The directional performance listed above assumes the microphone is measured without a fixture or any additional housing or packaging. The external delay is the time for sound to travel from the front sound port to the rear sound ports. The internal delay depends on the construction of the microphone element. The three available models have differing internal delays.

AMERICAS Knowles Acoustics 1151 Maplewood Drive Itasca, IL 60143 U.S.A. Phone 630-250-5930 Fax 630-250-5932

EUROPE Knowles Acoustics York Road, Burgess Hill West Sussex, RH15 9TT England Phone +44-1444-235432 Fax +44-1444-872772

JAPAN Knowles Electronics Japan, KK 2-2-16, Sangenjaya, Setagaya-ku, Tokyo 154-0024 JAPAN Tel. +81-3-5779-8503 Fax +81-3-5779-8523
1 of 9

ASIA Knowles Acoustics 5F, No. 129, Lane 235, Bauchiau Rd. Shindian City, Taipei 231, Taiwan Republic of China Phone 886-2-8919-1799 Fax 886-2-8919-1798
 

Construction All three DFG models have the same external construction.

Application Note

The height of DFG is slightly greater than FG due to the added thickness of the center plate.

Performance

The directional performance of DFG is 100% tested in production. For practical reasons, the production test uses a holding fixture that makes contact with the microphone terminals. The fixture slightly increases the external delay for the measurement. The measurement is made in a sound box to facilitate loading and unloading. The production test condition is described on Sheet of the model specification. Sheet of the model specification shows typical near field performance and directional performance in an anechoic chamber without a test fixture.

Typical near field response is measured with the microphone 6mm above the aperture of a B&K Type 4227 Mouth simulator. Typical far field and polar performance is measured 1m from the sound source in an anechoic chamber.

Typical Polar Performance is measured at 125Hz, 1kHz, 4kHz, and 10kHz.

Placing the microphone element in a housing will typically increase the distance between the front and rear port, which will make a cardioid pattern look more like a supercardioid pattern, and increase near field sensitivity.

Port Spacing

AMERICAS Knowles Acoustics 1151 Maplewood Drive Itasca, IL 60143 U.S.A. Phone 630-250-5930 Fax 630-250-5932

EUROPE Knowles Acoustics York Road, Burgess Hill West Sussex, RH15 9TT England Phone +44-1444-235432 Fax +44-1444-872772

JAPAN Knowles Electronics Japan, KK 2-2-16, Sangenjaya, Setagaya-ku, Tokyo 154-0024 JAPAN Tel. +81-3-5779-8503 Fax +81-3-5779-8523
2 of 9

ASIA Knowles Acoustics 5F, No. 129, Lane 235, Bauchiau Rd. Shindian City, Taipei 231, Taiwan Republic of China Phone 886-2-8919-1799 Fax 886-2-8919-1798
  

Application Note
typical performance The 1kHz polar pattern for measured at 1m in an anechoic chamber is approximately cardioid. The polar curves below represent actual data from a typical microphone output amplitude in dB relative to 0 degrees .

Zero degrees
180 degrees

The typical frequency response curves are based on the average performance of several microphones. For a near field application such as a headset, the designer may wish to add a filter to the microphone output to flatten the rising response at high frequencies.

For measurement, the microphone was suspended on lead wires for the typical tests as shown.

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Datasheet ID: DFG-30445-000 644930