Optimus Red

  • Class 2 & Class 1
  • Occupational noise measurement
  • Industrial hygiene measurements
  • Real time 1/1 octave band filters
  • VoiceTag audio note recording
  • Three simultaneous integrators


Optimus Red Accessories

Acoustic Calibrators

sound level meter acoustic calibratorfor Handheld Instrument Calibration
All noise measurement instruments should be calibrated before and after each measurement to ensure that they are measuring accurately and that your measurement comply with any standards or regulations that you need to meet.

All Cirrus noise meters, sound level meters and noise dosimeter can be supplied with an acoustic calibrator that has been specifically designed to be used with that equipment and that help you to ensure that your measurements are valid.

The CR:514 and CR:515 are high performance acoustic calibrators designed for the field and laboratory calibration of sound level meters and other noise measurement equipment.

The units are simple to operate and meet the requirements of the latest IEC 60942:2003 standard for Acoustic Calibrators with performance to Class 2 (CR:514) and Class 1 (CR:515) .

IEC 60942:2003 Class 2 & Class 1 Performance
PTB Type Approval for Class 2 & Class 1
94dB Sound Pressure Level Output
Suitable for use with ½” microphone capsules
Automatic power switch off with user override giving longer battery life
Robust case with ergonomic design
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Microphones & Preamplifiers

acoustic microphoneMicrophones, Preamplifiers & Accessories
Cirrus Research plc provides a range of measurement microphones, preamplifiers, power supplies and microphone accessories.

The Class+ Microphones are a range of high performance ½” Pre-polarised Electret condenser capsules designed for use on Sound Level Meters and Noise Measurement Equipment. The range also includes a wide range of accessories that enhance the performance of the Class+ Capsules.

Pre-polarised Electret Condenser Technology
International Standard ½” Capsule with Type 1, Type 2+ and Type 2 versions
Long Term Stability & Reliability
High Accuracy
Ideal for OEM Specifications & Replacement
Wide range of variants & accessories
Compatible with Brüel & Kjær Type 4155 & 4189
All of the Class+ capsules are based on the same technology, with all of the capsules being mechanically compatible.

At the top of the range, the MK:224 capsule is fitted to several leading brands of Sound Level Meters as well as PC based instruments and Noise Monitoring Systems. In many applications, the use of the most accurate microphone capsule is excessive, and a lower specification can be accepted. In these situations, the Class+ microphone capsules are ideal replacements for existing units at significantly lower cost, often less than 50% of competing units in OEM applications.

The MK:224 is the most accurate and stable of the Class+ Microphone capsules and is used on the Cirrus Research plc Type 1 Sound Level Meters, Noise Analysers and Noise Monitoring Systems. The excellent long term stability and temperature stability allow the capsule to be used in long term outdoor monitoring applications, and has been in use in Cirrus Research plc Airport Noise Monitoring systems over periods of many years.

The Class+ Microphone Series includes three other microphone capsules, the MK:226 Class 1, MK:216 Class 2+ and the MK:215 Class 2.

These capsules are produced using the same design and technology as the leading MK:224 capsule, but have reduced specifications

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Cirrus Research plc