Casella 1/2" Precision Electret Microphone Free Field Incidence

CEL-251 1/2" Precision Electret Microphone Free Field Incidence by Casella

The CEL-251 microphone is the best choice for use in ANSI and EC61672 Class 1 Sound Level Meters and other noise measurements requiring Class 1 (or precision) accuracy. It is a 1/2" prepolarized free-field measurement microphone whose development spans over 30 years in design, manufacture, calibration, and field-testing. Every capsule is supplied with an individual calibration chart specific to that microphone.

Key Features

• Pre polarized design can be used with preamplifiers that do not supply bias voltage
• Frequency range 20 Hz to 20 kHz ± 2 dB
• Free-field response
• Rugged design for long trouble free operating life
• Standard WS2 thread size for interchangeability with many popular measurement devices
• Measurements up to 146 dB
• Low noise floor for quiet background measurements

Applications

The CEL-251 is handcrafted to exacting standards along with rigorous mechanical and acoustic testing to ensure its high quality, reliability, and extreme stability in all kinds of environments. Its incredible performance stems from its nickel alloy diaphragm using the latest diaphragm coating technology. The CEL-251 microphone housing is also made from the same nickel alloy to ensure the smallest temperature coefficients.

Production quality control for the CEL-251 uses only 40% of the frequency response tolerances allowed by IEC61672 Class 1 microphones. The figure shows the typical free-field frequency response curve of the CEL-251 (black curve) against quality control limits (red curves). This ensures that the sound level meter or other measurement system connected to the microphone can use the other 60% of the allowed tolerances.

Each microphone is supplied with its individual calibration data for frequency response and sensitivity. Its stability and versatility has been proven in all fields of acoustic measurements. The capsule uses the international standard thread 60 UNS which ensures compatibility with a wide range of microphone preamplifiers and measurement instruments such as the CEL-600, CEL-400 and CEL-500 series of noise analyzers.