Sunday night was the 46th Superbowl played between the New York Giants and the New England Patriots at the Lucas Oil Stadium in Indianapolis, Indiana.

The National Institute for Occupational Safety & Health (NIOSH) who are based in Atlanta, Georgia set up a Twitter stream (#noiselevel) and asked anyone who was at the game to measure the noise levels using apps on mobile phones. They also had someone at the game who had a proper noise dosimeter.

This person measured the noise level at 107dB(A) LASmax when the Patriots scored and you can see this on a video here.

In 2006 we visited the San Diego Chargers to see a game against the Cleveland Browns and we used a Cirrus CR:110A doseBadge Noise Dosimeter to measure the noise levels over the game.

As the doseBadge can measure 2 channels at the same time, we set one channel up to measure according to the UK Noise at Work Regulations with a 3dB Exchange Rate, no threshold, no time weighting and a 8 hour criterion time. The criterion level was set to 80dB.

The second channel was set up with a 5dB exchange rate, an 80dB threshold, slow time weighting and an 8 hour criterion time. The criterion level was set to 85dB.

Below are the graphs of the noise levels in 1 minute samples. Each of the lines is a 1 minute sample (Leq or Lavg) and the red dots are the Peak(C) values in each of those minutes.

Channel 2 Leq & Peak(C)

Channel 2 - Leq & Peak(C)

Channel 1 Lavg  & Peak(C)

LavgTime History with Peak(C) values

Comparing the two channels

Although the data from these two channels look very similar, when they are put on the same graph, you can see the differences. The graph below shows the Leq (Blue) and Lavg (Green) along with the Peak(C) values.

Leq (Blue) & Lavg (Green) with Peak(C)

How different is the data?

One difference that you can see from the graph is that when the noise levels are below 80dB on the Leq trace (Blue), the Lavg values are lower. This is the effect of the 80dB threshold. Remember that the 80dB threshold means that any noise values that are below 80dB are considered to be zero by Channel 2.

The reason that there are values shown on the Lavg graph below 80dB is that each of the samples is an average over a 1 minute period and so there may have been noises both above and below 80dB during the 1 minute.

When the noise levels are above 80dB, the slow time weighting becomes a significant factor. Remember that the data used for the Leq values is simply an integration of all of the noise energy in that 1 minute whereas the Lavg is an integration of the noise energy after it has been passed through the Slow time weighting.

The effect of this is that when the noise levels are changing quickly, the Lavg will tend to have a lower value than the Leq.

Each time that the Chargers scored, a cannon fired! This is quite impulsive in nature and so the slow time weighting had an effect.

Numbers, numbers…

So, how loud was the game?

The highest 1 minute Leq was 106.5dB(A). Remember that this was an average over the 1 minute and so the noise will have been higher (and also lower) at some point during the minute. During that 1 minute, the Lavg was 104.9dB(A) and the Peak(C) value reached 127.7dB(C).

How different were the OSHA & UK configurations?

Although the highest noise levels measured were very close for both of the configurations, when you look at the noise across the whole measurement period, you can see some significant differences.

With the OSHA setup, we have an Lavg of 88.9dB(A) and a TWA of 88.1dB(A). With the UK setup, we have an Leq of 92.6dB(A) and an LEP,d of 92.1d(A). As discussed previously, the factors that contributed to these differences are the 80dB threshold and the slow time weighting used in the OSHA setup.

However, the most significant difference is when you look at these values as % Dose. For the same noise, the OSHA setup records a % Dose of 153% whilst the UK setup records the same noise at a 511% noise dose.

Remember that this is the same noise recorded by both channels and the differences reflect the different methodology in the OSHA and UK occupational noise standards.

In this example, the measurement period was 7 hours and 8 minutes which includes a couple of hours before the game and an hour after the game. the 60 minutes of actual play was spread out over 4 hours.

We’ve added a new date for the Cirrus Product Training Course for our customers in Northern Ireland.

On the 22nd February 2012 we are holding a Cirrus Product Training Course or CPTC at the Park Avenue Hotel in Belfast.

You can find more details of this course on our website. Click here for details.

Here are the current dates for all of our Cirrus Product Training Courses:

Wednesday 22nd Febraury 2012
Park Avenue Hotel, Belfast

Wednesday 14th March 2012
The East Midlands Conference Centre

Thursday 29th March 2012
Castle Combe Circuit, Wiltshire

Wednesday 4th April 2012
Oulton Park Circuit, Cheshire

Wednesday 11th April 2012
Brands Hatch Circuit, Kent

For more information, click here or visit our website at www.cirrusresearch.co.uk/training

We have a new job vacancy at Cirrus. This position is for Technical Customer Support.

Reporting to the Sales Director, you will be the initial contact for customer support and technical queries for both existing and new customers.

The role will be based at our head office in Hunmanby and you will be working closely with both the Sales and Marketing departments as well as with the other technical departments within the company.

You will also be responsible for updating the online knowledgebase and will be involved in the development of customer support tools such as training videos and user documentation.

This role would suit candidates with a service, test or technical background with some experience of customer support.  You will be familiar with Microsoft Office and other commonly used PC software packages.

You will also be responsible for documenting customer queries and liaising with different departments within the company.

This is an exciting opportunity to join an ambitious company with well-structured development plans. We are a growing company and are looking for employees who are seeking an opportunity where they can make a difference and build a career within a highly successful and fast paced business

More details can be found on our website at www.cirrusresearch.co.uk/careers

The NoiseTools software supplied with the optimus sound level meters can be run on most modern PCs.

To get the best from the software your PC should meet the minimum specifications below and where possible meet the recommended specifications.

If you are using functions such as the FFT analysis or 3D playback of audio recordings, having a faster PC with a dedicated graphics card will be beneficial.

Recommended PC specifications for NoiseTools

Operating System: Windows 7 SP1
Processor: 2GHz (dual core)
Memory: 2GB
Storage: 10GB free space
Display: 1280 x 1024 with a dedicated graphics card

Minimum PC Specifications for NoiseTools

Operating System: Windows XP SP2
Processor: 2GHz
Memory: 1GB
Storage: 2GB free space
Display: 1024 x 768

Please note that the installer will display a warning message if the PC does not meet the minimum specifications.

Storage space requirements 

The NoiseTools program requires the following space:

1GB for the NoiseTools program and dependencies
Up to 512Mb for temporary files during measurement download

The measurement database does not require significant space unless large amounts of very fast (ie. 10ms  ) time history are being downloaded.

Audio recordings can require large amounts of free space as follows:

Standard quality audio requires 115MB per hour
Studio quality audio requires 1.3GB per hour

If you are upgrading your PC to Windows 7 and you are using a USB connection to download measurements, you may need to update the drivers to allow your software to communicate with your instrument.

The information in this Technical Note covers the main instrument ranges and software packages and the steps needed to upgrade or update existing drivers.

You can download the information below as a Technical Note. Click here to download Technical Note 27 - Windows 7 USB Connectivity with Cirrus noise measurement instruments

Please note that the installation of the any drivers must be carried out using Full Administrator Access Rights.

If you do not have full administrator access rights, you will not be able to update or install the required drivers.

If you have any questions about the access rights available to you, please contact your IT support.

1 Instruments with a USB Port

1.1 CR:800C & CR:260A Sound Level Meters

The CR:800C and CR:260A instruments use an FTDI Driver which is supplied with the Deaf Defier software installation CD and as part of the software download.

To update the driver:

Step 1:  Download the latest driver from the chipset manufacturer website

Click here to download the latest driver. This is available as an executable file (.exe) or a ZIP file.

http://www.ftdichip.com/Drivers/CDM/CDM20814_Setup.exe

http://www.ftdichip.com/Drivers/CDM/CDM20814_WHQL_Certified.zip

Step 2: Disconnect the sound level meter from the PC and close the Deaf Defier3 software program completely.

Step 3: Run the driver installation program downloaded in step 1

Step 4: When the installation is complete, connect the Sound level meter to the PC. Windows will detect the new hardware and install the new driver. Deaf Defier3 will now be able to connect to the sound level meter.

1.2 RC:110A doseBadge Reader Unit

The RC:110A Reader Unit (USB) uses an FTDI Driver which is supplied with the dBLink software installation CD and as part of the software download available from the Cirrus website.

To update the driver:

Step 1: Download the latest driver from the chipset manufacturer website

Click here to download the latest driver. This is available as an executable file (.exe) or a ZIP file.

http://www.ftdichip.com/Drivers/CDM/CDM20814_Setup.exe

http://www.ftdichip.com/Drivers/CDM/CDM20814_WHQL_Certified.zip

Step 2: Disconnect the doseBadge Reader from the PC and close the dBLink3 software program completely.

Step 3: Run the driver installation program downloaded in step 1

Step 4: When the installation is complete, connect the RC:110A doseBadge Reader to the PC. Windows will detect the new hardware and install the new driver. dBLink will now be able to connect to the Reader.

Troubleshooting

The steps detailed above will install the correct Windows 7 driver for the RC:110A doseBadge Reader. If when the doseBadge Reader is connected to the PC, Windows 7 cannot find or install the driver, your Reader unit may need an upgrade.

The RC:110A doseBadge Reader units manufactured before 1^st July 2009 have a different USB driver in their internal software. This may prevent the new driver from correctly identifying the Reader.

These steps do not apply to RC:110A doseBadge Reader Units manufactured after 1^st July 2009.

If this occurs, you may see an error message such as “Windows cannot find the driver for this device” or similar.

Step 1: To resolve this issue, download the following ZIP and extract the program.

http://www.cirrusresearch.co.uk/files/tools/ReaderUSBUpgrade.zip

Step 2: Connect the RC:110A doseBadge Reader to the PC

Step 3: Run the ReaderUSBUpgrade.exe program and follow the on-screen instruction.

When the upgrade is complete, disconnect the RC:110 doseBadge Reader Unit from the PC, wait 30 seconds and reconnect. The new USB driver will be installed correctly.

Older instruments with a serial port

The older Cirrus sound level meters and doseBadge Reader units listed below are connected using an RS232 output. To allow these instruments to be used with a USB port, a USB to Serial Adaptor is required. Cirrus supplies the Sunix UTS1009B USD-Serial Adaptor and this has been tested with the instruments listed below.

RC:100A doseBadge Reader

RC:100B doseBadge Reader

CR:700 Series (All versions)

CR:800A Sound Level Meters

CR:800B Sound Level Meters

CR:260 Sound Level Meters (excluding CR:260A versions)

Sunix USB to Serial (RS232) Adaptor

Please note that if you are using a USB to Serial Adaptor that has not been supplied to you by Cirrus Research plc, we cannot provide support for these products. Please contact the vendor or manufacturer for support.

The Sunix USB to Serial Adaptor uses a driver and this must be the latest version to allow the unit to operate under Windows 7.

The CD supplied with the adaptor will include drivers but depending upon when the adaptor was supplied, these may not be compatible with Windows 7.

The latest drivers are available from the manufacturer’s website at www.sunix.com.tw

The Windows driver installer can be downloaded directly by following this link:

http://dl.sunix.com.tw/upload_product_driver/SUNIX.zip

To update the drivers:

Step 1. Plug in the USB to Serial Converter.

Step 2. Open the Device Manager. There will be a yellow warning icon shown next to any devices that are a problem.

Step 3. Locate the warning for the USB to Serial Converter and uninstall the driver.

Step 4. Unplug the USB to Serial Converter.

Step 5. Run the current Sunix installer software.

Step 6. Choose “Uninstall” from the options.

Step 7. When this is complete, run the Sunix installer software again.

Step 8. Choose to install a new version of the drivers.

Step 9. When the installation is complete, connect the USB to Serial converter and Windows 7 will load the correct driver.

Step 10. Check in the device manager that there are no warnings for the USB to Serial Converter.

This will have updated the drivers and the instrument should be able to connect successfully.

Today we’re launching our new 2012 ‘Noise in Action’ Photography Competition with the 12 winning images featuring in our 2013 charity calendar, on sale from the end of October 2012.

We’re looking for interesting, unusual and imaginative images of ‘Noise in Action’ to feature in the calendar. This could be anything from an image of our products being used in obscure or picturesque places to a photograph creatively illustrating noise, noise measurement or the impact of noise.

The first prize is a £150 Amazon voucher with the image featured on the front of the calendar and on one of the pages.

There are also 11 runners up prizes of £50 Amazon vouchers to be won for the images selected for inclusion, plus all of the 12 winning photographs will feature in our 2013 charity calendar.

Details can be found on the How to Enter pages and full Terms and Conditions are also available.

If you have any questions about what type of images would be suitable or how to enter, please contact us and we will be pleased to here from you.

The closing date for entries is the 31st August 2012.

Happy snapping!

Some older Cirrus sound level meters and doseBadge Reader units that had an RS232 data output were supplied with a converter to allow the instruments to be used with a USB connection. This converter is the Sunix UTS1009B.

The drivers supplied with this converter were compatible with Windows XP. If you have upgraded your PC to Windows Vista or Windows 7, these drivers may not be compatible. If you reinstall the software onto your new PC from the original CD, the older drivers will be installed and you may find that the software cannot connect to your instrument.

To ensure that the converter can be used with the latest versions of Windows, the drivers must be updated.

Please note that these drivers must be installed using full Administrator access rights.

The USB-to-Serial converter supplied by Cirrus is the Sunix UTS1009B.  The latest drivers are available from the manufacturer’s website at www.sunix.com.tw

The Windows driver installer can be downloaded directly by following this link: http://dl.sunix.com.tw/upload_product_driver/SUNIX.zip

To update the drivers:

1. Plug in the USB to Serial Converter.

2. Open the Device Manager. There will be a yellow warning icon shown next to any devices that are a problem.

3. Locate the warning for the USB to Serial Converter and uninstall the driver.

4. Unplug the USB to Serial Converter.

5. Run the current Sunix installer software.

6. Choose “Uninstall” from the options.

7. When this is complete, run the Sunix installer software again.

8. Choose to install a new version of the drivers.

9. When the installation is complete, connect the USB to Serial converter and Windows 7 will load the correct driver.

10. Check in the device manager that there are no warnings for the USB to Serial Converter.

This will have updated the drivers and the instrument should be able to connect successfully.

We’ve uploaded a new video that shows how simple our Trojan Noise Nuisance Recorder is to use.

You can find this video on YouTube:

Click here to view the embedded video.

or you can view it on our new video website at www.cirrusresearch.tv.

Happy viewing!

Windshields fitted to outdoor measuring microphones serve a dual purpose – to reduce wind-generated noise, and to protect the delicate microphone from damage by environmental factors such as rain, ice and dust.

However, the presence of a windshield inevitably affects the directional and frequency responses of the measuring system.

This paper presents results of measurements on the directional and frequency responses of a selection of windshield types under a variety of climate conditions such as rain and ice, and after typical wear such as bird damage and sunlight degradation.

The paper concludes with remarks on the potential for deviations in measurement performance due to the windshield when carrying out real-world environmental noise measurements.

Click here to download this paper as a PDF from our document library. 

As a motorbike track day enthusiast and rider myself, I have friends regularly asking me for advice when it comes to what is the maximum sound level their bike exhaust noise level can be.

When I reply with the question, ‘what circuit are you racing at?’ they seem surprised that this is relevant and that I was unable to provide them with a simple dB Level!

A circuit has individual noise levels in force depending on their surrounding environment; these considerations can include how close they are, for example, to residential properties, a hospital or a school. The decision of what this noise level will be is based on calculations on the levels coming from the track and how the noise propagates to these properties.

Circuits do not enforce levels just to spoil the fun of those wishing to enjoy the track. They will be enforcing noise limits to try to reduce as much as possible the environmental impact of their activities and to reduce the number of complaints from local residents. These limits are in place to protect the surrounding residents from intrusive noise. If a circuit continues to be a problem for local residents, there is a risk that the number of track days available to you and me could be reduced, or worse stopped completely.

To try and ensure the noise levels out on track do not breach the limits, you will normally have to be ‘noise tested’ in attempt to prevent any complaints.

This is sometimes referred to as a ‘static’ noise test as you are stationary and would usually be carried out after your safety briefing and before you are let out onto the track.

This test will be carried out in a designated part of the paddock. You will be tested in neutral gear and asked to hold you throttle open at around 2/3rds rpm. You will be told the actual rpm as this varies depending on the type of engine you have and will be different for different types of bike. You can ask your event organiser what rpm you will be tested at and what the dB limit is for your bike for a particular day as they will know.

There are some venues that have noise monitors around the siteconstantly monitoring the noise levels while you are out on track, so it is not advisable to tune your engine to have a ‘quite spot’ just for the static test if it’s a lot louder on track. It’s also not a good idea to take your baffle out or change your exhaust after the static noise test. It is quite likely that you will be spotted and possibly asked to leave the event.

Here are helpful pointers to consider:

1)      Check with the venue, organiser of the race event or track day as they will know the level you will be tested at.

2)      Note that just because it was a set level last time you were there; it may be different the next time you visit.

3)      If you have access to a sound level meter, test your vehicle before visiting to save any disappointment.

4)      Test your exhaust using the guidelines in the latest ACU (Auto Cycle Union) or MSA (Motor Sport Association) hand book. .

1. Hold the instrument as advised as this can vary your reading considerably.
2. Use a windshield (this is not an obvious requirement in some guidelines)
3. Do not do your test in your garage or on your driveway if you have a façade or wall close by as this will give you a higher reading.
4. Try and be considerate when doing this test as it can sound very loud in a built up area.
5. If you have access to an acoustic calibrator, use it. This way you can check your meter is working properly.

5)      If you are on a track day and are not an experienced racer, the chances are that having the baffle in or a quieter exhaust system will not actually alter the performance of your bike to a degree that you can notice. If you do find that there is a considerable drop in performance, it may be worth getting your engine re-mapped or tuned to suite the exhaust.

6)      If you are a racer and are lucky enough to have enough money to buy a new race exhaust system, many new systems do consider noise without losing performance.

One last important point that has resulted in many a disappointed rider being sent home is the misunderstanding that just because that an exhausts noise level is ‘road legal’, it does not mean that it will necessarily be suitable for every circuit.

Remember my point at the beginning. The noise levels limits that a circuit will use are determined by the environment in which they are situated and the type of events that they run, so if they are close to sensitive buildings or houses they may need to impose levels lower than those for a road legal exhaust.

The noise limits that a circuit will work to will usually be imposed and monitored by the appropriate local authority (usually the local council). As these bodies are responsible for dealing with noise complaints, they are the empowered to impose noise limits and to possibly restrict the activities of the circuit if these limits are not kept to.

Remember that a loud bike riding round and round a track really fast is going to be more annoying to local residents than the same bike riding  past a house, once!

If you require a pdf of the correct positioning of your microphone, you can contact me using the form on this page. Please put in your message “Exhaust noise blog”.

If you have any questions, please let me know!