Why Measure SPL?
One of the best ways to brag about your car audio system is by knowing exactly how loud it can get. Typically, a car sound system is anywhere between 90 to 130 dB. To put that into perspective, 90 dB is equivalent to heavy street traffic 5 feet away whereas 130 dB is considered the threshold for pain. A few other things to note is that an increase of +3dB is barely perceived by the human ear but +10dB nearly doubles the loudness to the human ear. At about 190 dB your ear drums will rupture and the pure sound vibration will be agonizing. So if someone says their system is pushing 200+ dB, then you should declare shenanigans and tell them to go rethink their entire life.
SPL, which stands for sound pressure level, is measured in decibels by an SPL meter. There are a couple different variations of an SPL meter depending on how accurate you need the reading to be. The first and most convenient way is via a handheld SPL meter. These are relatively inexpensive and are very simple to operate. They use calibrated microphones and amplification to measure the SPL level and display it on a digital display. You might not want to use this method for competitions or sound-offs seeing as it only goes up to 130 dB.
Smartphones offer applications that can measure SPL as well. If you have an Android phone check the app called “Noise Meter” and if you own an iPhone check out “UE SPL”. These applications use the phones built-in vocal microphone to measure the sound pressure level around you. Most cell phone microphones cut off at 90db however, so these apps are best used for measuring ambient sound levels. Most of these apps offer calibration so you can increase their accuracy if you have a more trusted device to compare it to.
Another variant that is far less practical and expensive but very accurate is Term-Lab. This is a precision system that utilizes hardware and software in order to measure the SPL level in the vehicle. It requires a computer or laptop and features precision SPL Sensors that attach to the inside of the windshield. It is used by numerous SPL organizations and even NASA uses it! If NASA says it’s good enough then there’s no way we can argue right? We decided to get one for our Sonic installation bay so I took a picture of it that can be seen on the right. We plan on using this for videos and events in the near future so stay tuned!
If you think you truly think you have the loudest system, then claim your bragging rights and comment below with your SPL level and equipment being used!