Greetings,
The FSAE rule EV4.14.3 states, "The sound level must be a minimum of 70dBA, fast weighting, in a radius of 2m around the car." What is meant by "fast weighting?"
Greetings,
The FSAE rule EV4.14.3 states, "The sound level must be a minimum of 70dBA, fast weighting, in a radius of 2m around the car." What is meant by "fast weighting?"
Jake Miller
University of Washington Formula Motorsports
Team 24-25: Electric Powertrain
I think I should start a new rule...
If I search for something and it is on the first page of Google search, you owe me a beer.
I searched 'fast weighting' in Google. This was the first link:
http://www.noisemeters.com/hel...q/time-weighting.asp
Time Weightings - Fast, Slow or Impulse?
Sound level measurements using any grade of sound level meter can be Fast, Slow, or Impulse time weighted. These weightings date back to the time when sound level meters had analogue meters and defined the speed at which the meter moved. Under Fast the needle would move fast to show quickly varying noise and under Slow the needle would be damped to smooth the noise out to be easier to read.
The Impulse time weighting is about four times faster than Fast, with a short rising time constant but a slow falling one. It is little used in most countries these days and so can usually be ignored.
Fast corresponds to a 125 ms time constant. Slow corresponds to a 1 second time constant. Impulse has a time constant of 35 ms.
As these time constants were set in standards, they have continued in digital meters, now being calculated or simulated before being displayed, stored or used to calculate other acoustic parameters that need the time weighting.
The following terms are used to express the sound level, clearly indicating the time weighting as well as the frequency weighting:
LAS Slow, A-weighted Sound Level
LAF Fast, A-weighted Sound Level
LCS Slow, C-weighted Sound Level
LCF Fast, C-weighted Sound Level
TL;DR Fast corresponds to a 125 ms time constant.
Kettering University Vehicle Dynamics
Formula SAE 2010 - 2015
Clean Snowmobile Powertrain 2012 - 2015
Boogityland 2015 - Present
+1I think I should start a new rule...
If I search for something and it is on the first page of Google search, you owe me a beer.
Though that would make some people in this forum an alcoholic right away
Regards,
Tobias
Formula Student Germany
FSE Rules & Organisation
http://twitter.com/TobiasMic
http://TobiasMic.Blogspot.com
Not many people know the difference between resolution and accuracy.
+1Originally posted by TMichaels:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">I think I should start a new rule...
If I search for something and it is on the first page of Google search, you owe me a beer.
Though that would make some people in this forum an alcoholic right away </div></BLOCKQUOTE>
Tobias you should remember that we're all already alky's anyway
South Dakota State University Alum
Electrical/Daq/Engine/Drivetrain/Tire guy '09-'14
Go big, Go blue, Go JACKS!
I am fine with that as long as you are able to stay dry during the event. We actually test that at FSG during the driver briefings
Regards,
Tobias
Formula Student Germany
FSE Rules & Organisation
http://twitter.com/TobiasMic
http://TobiasMic.Blogspot.com
Not many people know the difference between resolution and accuracy.
If your ready to drive sound is significantly louder than a normal conversation in a distance of 2 metres around the car you will most likely pass this test.Originally posted by jakem:
Greetings,
The FSAE rule EV4.14.3 states, "The sound level must be a minimum of 70dBA, fast weighting, in a radius of 2m around the car." What is meant by "fast weighting?"
Tilman Schröder
GETracing Dortmund, alumnus
University of Technology Dortmund, Germany
Ha ha...never heard of this "test" before...but yeah...I guess it sums it up.
_________________________________
Steve Works
decibel meter