I noticed No Limits at Donington have switched from 'Unsilenced' to 108db drive by with their track day info. Is 108db drive by super loud? The reason I ask is because I'm running a V4S with Termi's (no baffles) I'm booked on for 20th August with a bunch of other lads.
105dbA static at Brands equates to 102dbA drive by. 108dbA drive by is going to be over 110dbA static so you should be good. I was told at Silverstone to find out where the drive by microphone is located and short shift or back off the revs before you pass it. Andy
I think at Donington the mic's on the gantry on the start/finish straight.... which is of course exactly where everyone's giving it the beans. I guess I'll find out after the first couple of laps. I'm just back from Brno and according to people along the pit wall, my bike is a bit on the loud side But I'm hoping 108db drive by is next level loud. Fingers crossed....
You should be alright, I know it's the track it self that decides it but No limits are fairly leniant compared to MSV where noise or fun is strictly not allowed.
Measuring sound waves is a very "dark art" some frequencies are low dB whilst the human ear can perceive the same dB as very loud. 2dB increase can be felt nearly as double than the previous numbers ie 30dB vs 32dB What Andy wrote above doesn't makes sense to me. Stationary is measured at 6000-8000rpm(depending on cc and 2t or 4t) ..how can one estimate how loud would be the drive by for the same bike not knowing the revs whilst riding?(even if knowing the revs couple of 100 more or less can make a huge difference in the sound waves) 108dB is very loud as they won't measure 1feet away from the can. However, take some baffles to be on the safe side....
In the days MSV used to run 105dbA static days, 1 meter, at an angle of 45 degrees horizontal to the exhaust outlet, at 5500 rpm, my 853 passed the static but I got a warning that the bike was at the limit of the 102dbA drive by, measured by a microphone mounted on the pit lane wall at the exit of Clearways. My 1098R was measured at 105bA in the pit area at Silverstone but the bike didn’t get close to triggering the drive by limit measured at the MotoGP start line, or at least no-one came to tell me off. Warm, dry, days the bikes will measure louder than if it’s a damp day. My reply to @Mary Hinge was simply to pass on my experiences in the hope it would help, not to provide a technical treatise. Andy
My point was that we do know the dB at a set rpm, however difficult if not impossible to know the dB going up the rev range, also wind direction, adjacent buildings and humidity as you wrote have a great impact on the dB figures. Was just trying to give a different perspective, not saying what you wrote is wrong. Alex
