Class 1 Sound Level Meter vs Phone App

“I have a phone with a decibel app, why do I need a sound level meter?”

We’ve heard this before from SAE teams, but the reality is that to ensure your vehicle meets sound level requirements, your best bet is to make measurements with a calibrated Class 1 sound level meter.

Why? It all comes down to the quality and repeatability of the measurement. Most importantly, microphones are quite susceptible to environmental conditions. The best practice for sound level measurements is to calibrate your microphone and meter at the measurement location right before taking data by using a handheld, single point calibrator. This field calibration is essential to accurate, repeatable results that match the judge’s results.

Aside from lack of reliable calibration, phone apps may or may not report the sound level in the time or frequency weighting you need. It is very important to carefully read the requirements to understand that you are measuring to the correct metric. The quality and location of the phone’s microphone can also cause inconsistencies in sound measurement. Good quality sound level meters with precision microphones are able to calculate and report sound levels with multiple weightings and metrics, so you can rest assured the right data is available to you. Don't get an unwelcome surprise at competition!

Take a look at Larson Davis’  Sound Measurement Terminology page to learn about various acoustics metrics, including time and frequency weightings. Still confused? We’re happy to help.  Reach out to our Rental Team with questions!

The Modal Shop is happy to work with teams to loan equipment (as available) to help design and test Formula SAE and Clean Snowmobile vehicles. Below is a partial list of tools available in our rental inventory:

• Larson Davis Class 1 Meter 831C Sound Level Meter Kit
  • Equipment and brief training for objective measurement of Noise Scoring
  • Kit includes sound meter, microphone, preamplifier, field calibrator, tripod, and all associated hardware and software to setup the meter and download data.
• Larson Davis Human Vibration Meter Model HVM200
  • Vibration monitor, accelerometer, and software for ergonometric studies
• Accelerometers and  handheld data acquisition systems

* https://www.sae.org/about/

SAE International, a professional association and standards developing organization whose mission is “to advance mobility knowledge and solutions for the benefit of humanity,”* organizes competition opportunities known as the Collegiate Design Series.  Events such as Formula SAE® and Clean Snowmobile Challenge^® are intended to provide exciting competition based on real-world situations to help prepare engineering students for future employment. Both challenges include rules which limit vehicle noise.

"Formula SAE" and "Clean Snowmobile Challenge" are registered trademarks of SAE International