So you’re looking to purchase a new class 1 sound level meter (SLM). There are many SLMs out there, and many factors to take into consideration – the initial price tag is only one aspect of the lifetime cost of ownership of a sound level meter. This guide is designed to help you lay a basis for fair price comparison based on your needs.
Initial costs associated with a class 1 sound level meter
When browsing the market for a new sound level meter, there are a few things to take into consideration when requesting a quote from a supplier.
The kind of measurements you will be conducting determine what type of microphone you will need. You may only need one microphone to conduct all your work. But if you conduct a variety of measurements or measurements that require special microphones, make sure that the sound level meter is compatible with different microphones and make sure to budget for additional microphones.
Cheap noise meters have one capex cost, while most more advanced devices are modular with optional software licences. You might have very simple requirements, just needing to know the broadband noise level, or you might need to log noise with frequency data and high-resolution signal recording for later post-processing. This will significantly influence the size of your up front investment.
Make sure that you are comparing SLM configurations with the features you need. As minimum, your current measurement requirements should be covered by the software modules you include in your initial investment. Should your measurement needs expand at a later date, you need to consider selecting a modular meter where modules can be added.
You will need a calibrator to do field calibration on your sound level meter. Any quality SLM manufacturer will offer one, possibly in a bundle with the SLM. If you need to make legally relevant measurements, make sure the calibrator you are using is a listed accessory on the SLM’s type approval and that it is calibrated annually.
Sound level meters are capable of many different tasks, some of which require special dedicated accessories. For example, unattended longer term outdoor measurements require protection from the weather and tampering, and probably an outdoor microphone. Building acoustics measurements require an omnidirectional sound source, a power amplifier and a tapping machine. In such cases, you will need to budget for a much larger capex investment. And don’t forget the basics such as a tripod, windscreens, transducer cables and extension rods.
In addition to the initial cost of an SLM, there are other costs that need to be considered to calculate the lifetime cost of ownership.
Sound level meters need a laboratory calibration every second year. Although you can of course count on your new sound level meter to perform according to specifications, an initial accredited calibration certificate is sometimes required. Your field calibrator will also need an annual calibration.
When you talk to different suppliers of sound level meters, remember to get a quote covering your calibration needs. Some suppliers offer calibration contracts and some suppliers link their extended warranty agreements to calibration of the instruments, which gives you some insurance against potential repair costs.
Post-processing software specific for sound measurements will not only let you organize your recordings, but also perform calculations and present your data in a meaningful way.
Some manufacturers offer a free solution with basic data transfer functionality. Others have more advanced post-processing platforms intended for analysis and editing of the measurement data. Remember to include post-processing software in your considerations as this is licenced in most cases.
Indirect cost of ownership
Take a step back and look at the broader picture. What else drives cost and what can save you money in the long term?
The cost of rework
Labour is the biggest cost for consultants. This means that rework is extremely costly and must be avoided. In the context of an SLM, what is the cost of repeating a survey because of:
- unreliable equipment?
- incorrect set-up due to a confusing user interface?
- standards not being updated in the meter?
A couple of mistakes could cost more in rework than the purchase price of the SLM, particularly when other parties are involved, for example, measuring noise during a scheduled shutdown at a factory.
How many years will your equipment last? Can it take a beating?
Like any tool, proper build quality means that a tool will last for years and a quality sound level meter can last at least 10 years. So, the expected lifespan of a sound level meter is worth taking into account when considering the total cost of ownership or price per year of a sound level meter.
How many types of measurements do you need to make? And how many SLMs do you need? One for each type of measurement? Choosing a sound level meter with a modular platform that can be tailored to any measurement will often be a wise decision. Sound level meters are a capital investment, so buying a second one is no easy choice.
If you anticipate potentially needing to measure vibration at some point, consider buying a meter that can measure sound and/or vibration. This could save you having to invest in a vibration meter later. You will of course need the appropriate transducers for measuring vibration (accelerometer) but this can wait until the need arises.
One or two channels
Most sound level meters are single-channel devices. If you potentially need to measure sound in two adjacent locations simultaneously, then investing in a 2-channel instrument is worth considering. They are more expensive, but still a cheaper alternative to two sound level meters. The best 2-channel SLMs can handle a sound intensity probe. This makes it possible to declare emitted noise from devices, in terms of sound power, according to acknowledged international standards. The most advanced 2-channel instruments can even measure one channel of sound and one channel of vibration.
Personalization might seem like a counterintuitive concept in a world of standards, but while there are lots of choices that are made for us, setting up a sound level meter to do specific jobs with our preferred shortcuts and settings, and local language can save precious time especially for non-expert users.
Being familiar with your equipment is crucial for success in the field. Even though you have made sound measurements before and know the standards for which to comply, class 1 SLMs are often complex machines with multiple options. Learning the logic of a new instrument can take a while. If you want to get up and running quickly with your sound level meter, user training can be a good option. Some manufacturers offer a broad range of online and in-person training locally and according to local standards, so check this with providers before purchasing a new SLM.
Lifetime cost of ownership for a sound level meter
There are some costs that aren’t obvious in regard to owning a sound level meter. As we have seen in this article, the lifetime cost of ownership is worth keeping in mind when considering which class 1 sound level meter to buy.