Sound Level Meters
Optimus green
The Optimus Green sound level meter is for measuring environmental noise in communities and around the outside of industrial sites.
- Environmental noise surveys - long term or short term
- Occupational noise
- Noise Ordinance and Community noise assessments
- Mix of industrial and residential - e.g. BS4142 standard
- 12 year warranty
- Audio recording
- Voice tag recording of comments
- Single range 20 to 140 dB
- Real-Time Octave Band Filters included
- Real-Time 1/3 Octave Filters as an option
The Optimus Green sound level meter is available as either Class 1 or Class 2 - the most common for environmental noise measurement and more accurate being Class 1. This meter also has everything needed for occupational noise measurement in line with the Noise at Work regulations, making it ideal for anybody involved in both environmental (outside the factory) and occupational (inside the factory) noise.
There are many features included with this meter that are designed to make the task easier. Functions such as a single measurement range, voice notes and audio recording are included in all Optimus Green meters.
The Green range also includes real-time octave band filters and data logging with software and download cable. They measure A, C and Z frequency weightings simultaneously along with Fast, Slow and Impulse time weightings.
Our Recommendation
Most environmental noise surveys demand the use of a Class 1Sound Level Meter that can make repeating measurements, such as the 5 minute LAeq and L90 (background noise).
We recommend the Class 1 Optimus Green with Data Logging (order code CR171A ). If there is any noise with a high tonal content, then the 1/3 Octave Band option is recommended (order code CR171B).
All environmental noise regulations demand the use of a Sound Level Calibrator. We recommend the Class 1 Calibrator, order code CR515.
Environmental Noise Measurements
The Optimus Green sound level meter is capable of measuring the noise parameters required for most environmental noise surveys. It is ideal for both short term and longer term measurement, when installed in a weatherproof outdoor kit.
- Periodic LAeq and Ln (e.g. L10, L90, etc.)
- Maximum and minimum sound levels
- Time history (see below)
- Dates and time
- Real-time 1/3 octave band filters (option)
- Voice tag recording
- Audio recording
Simultaneous parameters in a single span
To keep things sensible, the meter displays just the main parameters (Leq, Ln, etc.) on its display. However, it simultaneously measures all installed parameters, so you can sure of missing nothing. These parameters can be viewed on the display or, more usefully, after download.
Noise Measurements Stored
With 4GB of memory the Optimus has plenty of space to store thousands of measurements. The acoustic parameters stored can be logically separated into two groups:
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Periodic Summary
Whenever you press Start and then Stop, you get a summary of the noise. For environmental surveys, theStart/Stop process is usually run automatically, repeating every 15 minutes for example. The summary typically consists of the following parameters describing the noise in detail:
- LAeq (average sound level)
- Ln values, including the all important L90 (background noise)
- Lmin and Lmax (minimum and maximum sound levels)
- Date, time and running time
Many other parameters are stored, but these are the more important ones.
Time History
On top of the summary data above, the meter continually stores a number of parameters, typically every second, but the rate can be between 10ms and 2 seconds. When downloaded to a computer, this gives a detailed and very useful graph of the noise levels over time.
Although the Time History is not usually a requirement of the regulations, it is extremely useful when presenting a picture of the noise. It also offers the ability to zoom in on different times of day and recalculating the Leq for other time periods.
Real-Time Octave and 1/3 Octave Band Filters
All Optimus Green meters come fitted with real-time Octave Band Filters (1/3 octaves are available as an option). Octave Bands are ideal for basic analysis and are particularly useful for occupational noise assessments with hearing protector selection.
When assessing environmental noise with a tonal content, it is often necessary to make measurements in the 1/3 Octave Bands. The 1/3 Octave Band option provides real-time analysis from 6.3 Hz to 20 kHz.
Real-Time: The Optimus sound level meters have real-time filters, often called "parallel filters", so all bands are measured at the same time. This makes the meter much quicker and easier to use than one fitted with the older serial style filters.
Like the Time History store, the Octave or 1/3 Octave Band measurements are stored typically every second, giving a very detailed frequency analysis of the noise in question.
Voice Tag and Audio Recording
The quickest way is to take notes about a measurement is to make a brief recording just before making a measurement. The Voice Tag stays with the measurement when it is transferred to the computer. With the Audio Recording feature, you can also choose to record the sound during measurement for playback on the computer or for more detailed analysis.
The Voice Tag feature is included with all versions of the Optimus Green sound level meter.
Before starting a measurement, the meter will ask if you want to record a "Voice Tag". The meter will record any speech or the noise in question (to help you identify it later) for up to 30 seconds. This audio is transferred to the software automatically along with the measurement.
You can skip this stage if you don't need a voice tag, or the option can be disabled altogether.
When viewing the measurement on a computer the Play Voice Tag button lets you listen to the recording on the computer's speakers.
The Audio Record feature is included with all versions of the Optimus Green sound level meter. If you choose to enable it, the meter will make a recording of the audio during the measurement. Its uses are:
- Play back on the computer so you can identify the noise source
- Further analysis of the noise using the Noise Tools software
The audio is stored along with the measurement, making playback and analysis more convenient. Depending upon the way you want to use the recording there are two levels of recording quality:
- Standard Quality - a very good quality of recording for playback.
- High Quality - an extremely high quality recording for playback and for further acoustic analysis.
Environmental Noise Measurement
The Green version of the Optimus Sound Level Meter is ideal for almost any type of noise measurement, but it has been optimised for Environmental Noise Surveys. It provides all the parameters and features that are usually needed, and of course it meets the very demanding acoustic standard IEC 61672 to Class 1.
- For environmental and community noise assessments
- Ideal for BS4142, PPG24 and related regulations
- Noise in mixed industrial and residential areas
- Environmental noise surveys around factories
The following features are available with this meter, all designed to make the acoustic measurement process quicker, easier and more accurate:
- Class 1 to IEC 61672, Type 1 to IEC 60651 and IEC 60804
- Measurement of Leq, Ln (L90, etc) and many other parameters
- Automatic, repeating measurements for longer term assessments
- Real-time 1/3 Octave Band Filters option
Calibration Check
Most regulations and measurement standards state that the meter's calibration should be checked before making measurements.
Fit the Calibrator over the microphone as shown on the right, switch it on and press the Calibrate button. The meter will automatically make any adjustments.
Calibration details are stored in the meter so that you can either make note or download them to a computer if you have the data logging option.
Manual Measurements
Press the Start key, shown on the right to begin the measurement process. If you have the data logging option fitted then the meter will ask if you want to make a Voice Tag recording.
The meter will start measuring the LAeq and other parameters that are needed for environmental noise surveys.
When you are happy that you have measured for long enough simply press the Stop key.
Recording Audio
The meter can record the audio - so you can listen to the actual sound later. Audio recordings can be started manually or when a trigger level is exceeded.
To start a recording manually press the Audio button during a measurement.
The Audio Recording can be set to start automatically when a certain level is exceeded. For example, you can set it to make a recording when the level exceeds 65dB(A). You can even set it to trigger when the trigger level is exceeded in just one band to detect tonal noise. Adjustable smoothing factors are available to avoid triggering on very short term noise.
Automatic, Repeating Measurements
For many environmental noise surveys, you need periodic (usually 5 minute, 15 minute or 1 hour) measurements showing values such as the Leq and the L90.
To make this type of measurement, use the Menu key to set the meter to make repeating measurements of the required duration. The meter will now run for the specified period. It will then stop, store the results and start again automatically.
It is better to mount the meter on a tripod for this type of measurement. A tripod mount is included on the back of the meter. It can be fitted to a standard camera tripod, or we can provide you with a suitable one.
1/3 Octave Band Measurements
The meter will automatically store the octave band spectrum (and 1/3 octave band spectrum if fitted) at the selected rate. One of the most useful features of this meter is that you do not have to tell it what to measure, or even what range to use. Everything is measured and the wide-span meter covers the whole range from 20 to 140 dB(A).
Even the standard meter measures the real-time Octaves.
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Download the Optimus Green |
Contact Midas
Midas Safety Services are happy to discuss your Sound and Noise Level Testing requirements and arrange a no-obligation meeting if that would be helpful.
Please contact us on 01454-632967 or email chrisgray@midaselectronics.co.uk.
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