As of 2019 fines are mandatory, and can range upwards of 1,000. Prior to 2019 police officers issued so-called fix it tickets, enabling you to fix your vehicle’s exhaust system within 30 days, provide proof, and avoid paying paying fines. If you guys would be so kind as to give me the decibel ratings of any siren that you know of that isn't on this list, I will add them. The decibel scale measures sound pressure level on a logarithmic scale (based on the power of 10) the human ear’s response to noise levels is also approximately logarithmic too. AB 1824 enables law enforcement to issue immediate fines for violating exhaust levels. However, it's far from complete, so I'll need YOUR help to finish it. Most of these were obtained from the company websites (Though for some reason I cannot access the Whelen company page, that's why I don't have any on this list.), or from other various places online. Generally, a rating of 65 dB or lower is considered quiet, while a rating of 85 dB or higher is considered very loud. Electrical power and acoustic intensity are power quantites. The higher the decibel rating, the louder the sound. The beauty of decibels is that they allow us to understand and calculate the differences between power, root-power and perceived quantities in sound and audio.
Here's what I have so far, from loudest to quietest. This -20 dB means we have 0.1x (1/10 x) the sound pressure level and 0.01x (1/100 x) the power. I don't think there's a list like this anywhere (At least, I haven't found one.). This is something that I've been working on for the past few days.