BL-21994-000 Knowles Acoustics, BL-21994-000 Datasheet - Page 15

• Manufacturer Part Number: BL-21994-000
• Description: MIC ASSY PIEZO INSTR W/38" CABLE
• Manufacturer: Knowles Acoustics
• Series: BLr
• Type: Piezo Condenserr

Specifications of BL-21994-000

• Sensitivity: -69dB ±3dB
• Voltage - Rated: 3V
• Current: 160µA
• Size / Dimension: Circular - 12.7mm Dia x 25.4mm H
• Impedance: 4K Ohm
• Frequency: 20Hz ~ 10kHz
• Termination: Wire Leads
• Direction: Omnidirectional
• Port Location: Top
• Diameter: 12.7 mm
• Transducer Function: Microphone
• Device Type: Microphone
• Directivity: Omni
• External Diameter: 12.7mm
• Output Impedance: 4000ohm
• Length: 25.4mm
• Outer Diameter: 12.7mm
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Filter Type: -
• S/n Ratio: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: 423-1002; BL-1994; BL-21994; BL1994

Note: All performance curves are typical
Specialty Transducer Speakers
Knowles sub-miniature speaker designs are based on balanced armature technology and are
utilized in a variety of high performance audio and communication products. Knowles balanced
armature speakers are available in several sizes and efficiencies, which can be finely tuned to
meet your specific performance requirements. They are designed for use in in-ear applications,
including earphones and communication earpieces, or be sub-assembled by Knowles for
premium consumer electronics accessories.
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TWFK SERIES
The world’s smallest dual balanced armature speaker, the TWFK is designed for
pro-audio in-ear applications. Enables customized cross-over systems to achieve
target frequency response in a package size smaller than the ED Series.
WBFK SERIES
Same package size as FK Series, WBFK has extended high frequency response.
It is recommended as a high frequency component to be combined with low/
midrange speaker for music earphones.
High efficiency, stability and reliability
Customizable performance and port locations
Ideal for premium in-ear designs
Component and subassembly solutions
M M o o d d e e l l
TWFK-30017-000
M M o o d d e e l l
WBFK-30095-000
– Dual Balanced Armature Speaker 5.00 x 2.73 x 3.86 (mm)
– Wideband Balanced Armature Speaker 5.00 x 2.73 x 1.93 (mm)
Sensitivity @ 1kHz
Sensitivity @ 1kHz
(dB SPL)
(dB SPL)
95
91
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Single sound port for simplified earphone design
Extreme wideband frequency response
Unique woofer/tweeter combination
Enables leading-edge earphone designs for size and performance
Lower low/mid-band sensitivity compared to FK Series
Best high frequency response of any Knowles element
Combine with low/mid-range speaker for
extended frequency response
TWFK pairs WBFK with low frequency FK
Port Location
Port Location
12S
12S
www.knowles.com
Impedance @ 500Hz
Impedance @ 500Hz
SPECIALTY TRANSDUCERS – Speakers
(Ohms)
(Ohms)
13.5
31
Max SPL @ 500Hz
Max SPL @ 500Hz
(dB SPL)
(dB SPL)
106
101
110
105
100
110
105
100
95
90
85
80
75
70
95
90
85
80
75
70
Max SPL @ 1st Peak
Max SPL @ 1st Peak
100
100
(dB SPL)
(dB SPL)
113
114
2
2
3
3
4
4
5 6 7 8 9
5 6 7 8 9
FREQUENCY (Hz)
FREQUENCY (Hz)
1k
1k
2
2
3
3
4
4
5
5 6 7 8 9
6 7 8 9
10k
10k
15