Just got back from a 2 day novice school at Laguna Seca Raceway (had a blast ) but was flagged twice for exceeding the 92db sound limit. Late in my first day as I was picking up speed with LV pipes + modified/extended inserts I was told I got a reading of 92.6 db. Luckily it was at the last session of the day and I went ahead with swapping out to stock pipes again. Bike sounded very quiet in the paddock to me. Sunday, went back out and on the 2nd session let it roll on hard to Turn 6 and was pulled off for a reading of....97.8 db! wtf?

From that point onward I was really neutered going up that hill by the sound booth, short shifting/lugging/maintenance throttle and this was apparently fine, but it sucked. A fellow with a Tuono and another with a Panigale were also pulled off for noise while using stock pipes....but that ducati was LOUD even with the stockers. There were also a handful of IL4's pulled, but they all seemed to have slip-ons. Meanwhile my buddy on a cbr600 could redline up that hill and not get flagged.

I don't know the physics, but would a lower exhaust note trip higher dbs? Perhaps it's my airbox induction and not the exhaust note? just wondering

92dB......

While you are ignoring it.......

Do not shoot this sign

Oops - wrong thread

Decibels db is a misleading word. What is really measured to determine loudness is sound pressure (Pa for pascals, or N/m^2). Decibel scale is used rather than a linear scale, so it's decibel pascals or just db. When you think of it in terms of pressure, it starts to make more sense. Sound level meters measure sound pressure, but also factor in frequency. Frequency as you probably know is cycles/second or the number of waves transmitted per second. Naturally, the more sound waves you have the more annoying it is to the ear, and it is perceived as louder. Plus, high frequency sound also causes the most damage to the ears (banging on the drum more often). Industrial Sound Level meters for public safety factor in the frequency for this reason, they use either A or C weighting. If the meter says dBA, then it is using A-weighting which is most common. So, even though you might have a bass drum sound at the same amplitude (energy level) as a whistle sound, the whistle will record a higher dBA level on the meter since it's more damaging.

92 db? That's low, and I've been to Laguna Seca and don't remember it being in a built up area. British circuits normally have a 100db limit and they have houses within spitting distance in some cases.

Do they have noise limits at Bonneville, lol.