To begin with, lower-quality measurement microphones result in lower accuracy. According to ISO 5725-1, accuracy consists of trueness (proximity of the mean of measurement results to the true value) and precision (repeatability or reproducibility of the measurement)
Precision is the ability to make multiple measurements and get comparable results.
Poor precision
Good precision
Trueness is the degree to which a measurement’s result conforms to the correct value of the measured physical phenomena.
Poor trueness
Good trueness
Trueness and precision in a measurement
A lower-quality microphone will be unstable when exposed to temperature or static pressure changes and humidity, resulting in widespread non-repeatability. Lower-quality microphones also often result in less true and less precise measurements. This leads to fluctuating data, which is particularly problematic if your business relies on accurate sound measurements for product development, quality control, or compliance with standards. Imagine trying to precisely adjust a product with the help of measurement microphones that have poor trueness and precision. This would be a very challenging task.
The main limitation of an acoustic measurement setup is, with very few exceptions, the measurement microphone. Because it is the first link in the measurement chain and the real interface to the physical phenomena observed, the trueness and precision of the total chain will never outperform the microphones, regardless of how the rest of the measurement chain is designed.
In short, no matter how hard you try, it will be challenging to adjust your product with better trueness and precision than the weakest link in the measurement chain: the microphone you are measuring with.
Trying to compensate regularly for sensitivity deviation only partially solves the problem. First it is time consuming, and it often results in deviations in the high-frequency response.
Unhealthy microphone corrected for sensitivity
This will, in a testing situation, lead to two main types of errors.
The first type of error will be a false negative. A perfectly good product will be considered faulty and sent back to the floor to be fixed and/or simply rejected. This will lead to added costs due to rework, repair and retesting or simply scrapping and recycling.
Good product measured with a healthy measurement microphone
Good product measured with an unhealthy measurement microphone
The second type of error – the false positive – is the most damaging. A faulty product can be qualified as good and sent to customers.
Faulty product measured with a healthy measurement microphone
Faulty product measured with an unhealthy measurement microphone
Selling products that are not living up to the expected brand quality will result in the product being returned. Product returns not only directly impact a company’s bottom line (added costs related to shipping, handling, restocking and discounted resale), but also damage the company’s reputation and trust. They are a major indicator of customer satisfaction and perceived product quality. Poor customer experiences, magnified by social media and online reviews, can discourage potential buyers, impact long-term revenue, and lead to lost sales. Forbes estimates the cost of returning a $100 product to be $66 (see here).
The real question here is how much time and money you can save by utilising microphones you can trust, compared to the cost of having to stop a production line more frequently to ensure that your measurement chain is healthy.
Each minute spent stopping a production line to validate microphone sensitivity can be translated into a significant cost. The cost of a minute used for validation must be multiplied by the number of microphones on the production line, the time taken to validate each microphone, and the number of daily verifications. Not forgetting the cost related to the acoustic engineers dedicated to calibration tasks and services.
Make no mistake, initial calibration and regular validation of the measurement chain are crucial for ensuring the necessary levels of quality control. However, using reliable microphones reduces the numbers of validations needed, optimises yield, and minimises the risk of retesting.
While investing in more affordable testing equipment might initially seem like a cost-saving measure, it often leads to higher expenses due to operational disruptions, additional services, retesting, product returns, and brand damage.
On the other hand, using high-quality microphones can save money in the long run by minimising these disruptions, reducing rework and product returns, and protecting your brand's reputation and customer satisfaction.
Your business deserves an upgrade to high-quality measurement microphones.
Article 1
What to expect when using lower quality measurement microphones
Article 2
What are the implications of using lower-quality measurement microphones
Article 3
Coming soon
This will bring together HBM, Brüel & Kjær, nCode, ReliaSoft, and Discom brands, helping you innovate faster for a cleaner, healthier, and more productive world.
This will bring together HBM, Brüel & Kjær, nCode, ReliaSoft, and Discom brands, helping you innovate faster for a cleaner, healthier, and more productive world.
This will bring together HBM, Brüel & Kjær, nCode, ReliaSoft, and Discom brands, helping you innovate faster for a cleaner, healthier, and more productive world.
This will bring together HBM, Brüel & Kjær, nCode, ReliaSoft, and Discom brands, helping you innovate faster for a cleaner, healthier, and more productive world.
This will bring together HBM, Brüel & Kjær, nCode, ReliaSoft, and Discom brands, helping you innovate faster for a cleaner, healthier, and more productive world.