The Brüel & Kjær 4220 Pistonphone is precision sound calibration equipment designed for calibrating microphones and compatible sound measurement systems. The 4220 produces a nominal 124 dB sound pressure level at 250 Hz, making it suitable for laboratory and field calibration applications.
The unit uses a piston-based acoustic source to provide a defined calibration signal for compatible microphones and measurement equipment. The 4220 is associated with Brüel & Kjær of Denmark and was designed as a portable calibration instrument for precision sound measurement systems.
The 4220 is a practical addition to acoustic measurement equipment, laboratory instrumentation, or vintage Brüel & Kjær collections. Please verify the microphone adapter, barometer, batteries, calibration status, accessories, physical condition, and overall operation before purchase or use.
Key Features
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124dB: Nominal sound pressure level is 124 dB at 250 Hz.
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B&K: Brüel & Kjær branding provides clear manufacturer identification.
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4220: Specific model number supports accurate equipment identification.
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Denmark: Brüel & Kjær equipment is associated with Danish manufacture.
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Pistonphone: Precision acoustic source provides a defined calibration signal.
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250Hz: Standard operating frequency supports compatible calibration procedures.
- Barometer: Compatible barometer provides ambient-pressure correction information.
Specifications
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Model: 4220
- Origin: Denmark
- Brand: Brüel & Kjær
- Output: 124 dB at 250 Hz
- Type: Pistonphone / Sound Calibrator