What a friggin JOKE! Thanks for being so concerned about street & dirt bike riding rights!

By what I read,their proposal requires bikes ridden on the street to not exceed 96 Db at 2000 RPM or 75% or their redline RPM, whichever is lower.

Someone correct me, PLEASE!!!

OK, your bike at 2K, (is any bike even built with a 75% REDLINED rpm UNDER 2K???) is 96 Db, but when you wack the throttle open and are at 7k, 9k, 15,000 RPM you can be as loud as you like. LOL!

I luv this fake test BS.

"But Officer, my bike meets the requirements set by the AMA!"

Big deal, your town, city or state leaders will still be invoking bans & anti bike legislation as you will still be pissin all over the public who complain about loud bikes. Just like before you came up with a arbitrary & ineffective test standard. WHOOPIE!!!

And, like the BS testing 50% RPM MX standard at 96Db, though the bikes could be 200 Db at WOT. Why bother, just to say you did "something"? The results are the same, loud bikes & less riding because of it.

Max Db at max RPM is the only measurment that matters.

Thanks again AMA!

jjm525 said:

OK. :lol: :lol:



Jim, just a FYI so that you have your facts right.

1.) - it's dB, not Db.

2.) - 200dB is theoretically impossible. The human preceived loudness in sound DOUBLES approximately every 3dB - ie: 100 to 103 dB is twice as loud. So from 96dB to 126dB is 1000%'s (literally) louder.

3.) - Sustained exposure to sounds over 90-95dB will cause permanent hearing loss long term. Hearing is not "regenerative". For instance, OSHA only allows for sustained levels of 95dB for 3 hours a day - MAX - before you will begin the hearing loss process.

4.) A Jet Engine is somewhere around 140dB and I've yet to hear any motorcycle to approach that. The destruction of the hearing tissue in your ears - and I mean COMPLETE DESTRUCTION - starts right at 180dB. The theoretical loudest noise that can possibly be made is 194dB.

Wear hearing protection if you've got loud pipes guys!!!!


PS - I completely agree with your rant, but I thought you'd like to get your facts straight. (Audio professional here.....)

Cheers,

bp

well if we're going to get some facts straight, lets get them straight.

3db IS a doubling of power and is twice as loud, however to be perceived as being twice as loud to the human ear, its generally acceptable to say you need a 10db increase.

secondly, aircraft engines are usually measured in dBA, not dB, which means it adjusts the measurement to account for the way the ear responds to different freq of sound.

I disagree with your rant. Various towns and localities have been making their own laws to try to combat the problem of excessively loud motorcycles because there has not been a single standard or well defined test to enforce that standard. Now that they have the standard and the method to enforce it, we should see a decrease in haphazard and prejudicial laws on the books that single out motorcycles. This is good for motorcycles.

The test we are talking about applies to all road-going vehicles, so this may explain the low RPM/redline option since large diesel engines in buses and trucks don't rev high.

I'm no audio engineer (no shat he says:smirk: ) & couldn't care less if its a DB, Db dB or db.

200 was an exaggeration, that much I know, LOL. (Lol, lOl, loL, you get the idea...) Got your attention & finally a reply afterover 100 views! ***?

96 dB (that still dosen't look right!) is what my 450 MX bike with an open can puts out at 50% max RPM. That bike can hit 117 dB without much effort. I've seen over 120 dB on the meter as 450s & ATVs blow by it. Way to make a stand by the AMA (AmA, Ama, aMA, whatever!!!)

They are pretending to institute a standard that they assume will be adopted by the fed, state or local governments, laughable. Why bother? That was the point of the rantification. At WOT a "96 Db @ 2K rpm bike" could still hit levels that would be easily classified as offensive. Deafening even. Agreed? My friggin dues $$$ so they can chase their tail & say "look what we did!" :worthy:

If not for racing I'd wouldn't send these clowns a red cent. They claim to fight for riding rights while buckeling under to the typical "loud pipe lifestylers", utter nonsense. I couldn't care less when all they did was fight helmet laws, had no effect on my riding at all. This issue is, for now, the #1 anti-motorcycle (street or dirt) issue & they suggest basically nothing. Thank you & your team of "scientists".

Lets adopt this. The complaints against all bikes & quads will continue to local & state PDs & councilmen, mayors & governors, more land & street bans will be brought forth as a result & everyday someone will ask right here "what the loudest pipe for my KLR"?

I still don't feel better about it, even with a double rant, dB or Db. :banghead:

gotta double up...didn't see that one.

quote"...Various towns and localities have been making their own laws to try to combat the problem of excessively loud motorcycles because there has not been a single standard or well defined test to enforce that standard."

This test will pass 99% of the same bikes that generate complaints. How does that address the problem? The guy who rides past at 7k with fishtails on a HD will pass this test & still shake your windows. The GSXR with a D&D will pass at 2k RPM & still be audible at over 2 miles at 15k RPM.

Having a standard for the sake of saying you did is meaningless. The results will matter, not the BS standard they suggested. Bikes at my MX club track meet the AMA standard, doesn't stop the neighbors from conmplaining & nearly shutting us down. They don't care about what little standards the AMA sets, they don't want the thunderous noise invading their lives.

jjm525 said:

That's the bottom line, clear and simple. If we don't mitigate the preception that John Q Public has about us, we're dead - as there's a lot more of them than there are of us. Pretty soon tracks will be gone or electric bikes only if we can't control the noise. The population is only getting denser on this planet....

PS - wasn't trying to aggrivate you with my original post, but if you're going to do battle with Goliath, having the right terms and knowing the basics will help. :thumbsup:

I was laughing when I read you reply, no offense here, I'm surprised there weren't more mistakes in my OP! Just BBalls back, end of ride tailgate humor only. Thanks for pointing it out, though I'm pretty thick & I've been typing it wrong for sooo long... I'll always have to look it up now! I'll never be sure! Thanks!

jjm525 said:

How about a link to where you read this?

Ride on
Brewster

AMA magazine. I thought I already tossed it... Page 46, September issue.

"for bikes with fewer than 3 cylinders...(ahem, HD) or more than 4 cylinders, 2,000 RPM or 75% of maximum engine speed, whichever is less. 96 dBa with a 2 dBa wiggle for "certified" & non-modded exhausts. Translation, 98 dBa at 2k RPM.

100 dBa for 3-4 cylinder engines @ 5k RPM or 75% max, whichever is lower

and a max 92 dBa at idle for all.

or...102 dBa for 3 & 4 cylinder bikes with a stamped can, 94 dBa at idle.

All measured 20" at a 45 from the rear of the exhaust. Easy enough for a cop to figure out roadside? HaHa!

Now I need one of the sound guys to translate dB to dBa please.

jjm525 said:

The "a" in dBa is a scale corrected to mimic the audio response of the human ear.

http://www.phys.unsw.edu.au/jw/dB.html

Ride on
Brewster

This much I knew, "Many such regulations have a limit for exposure to continuous noise of 85 dBA, for an 8 hour shift. For each 3 dB increase, the allowed exposure is halved. So, if you work in a nightclub where amplified music produces 100 dBA near your ears, the allowed exposure is 15 minutes."

My head started spinning after the first equation on that page.

At the twin cylinder allowed AMA output, you'd be violating most fed work standards well within 30 minutes of exposure.

How does a dBA, lets say 96 as I and many others know what 96 dB sounds like from event testing at 50% RPM max, compare? Is 96 dBA louder to the human ear than 96 dB? Or perceived as louder anyway?

The A weighted scale is frequency dependent, just like our hearing. With a constant sound pressure level, the human ear and the A scale, perceive the level to roll off below 1 kz and above 8 khz in the average ears. Scroll down in the previous link and you can see a graph.

Ride on
Brewster

Ahhhhhhhhhhhhhhhhhhhhhhhhhhh!

***??? I've reread that page over & over and it isn't making much sense to me as applied to my question. I'm sure the answer is there, I just can't connect the dots.

Either way, the proposed measuring test it a BS move to claim they are trying to help address the problem while still allowing the mega loud majority to continue business as usual, which is hurting all our riding rights. You can't blame the public, they won't care if the bikes pass a super low sound standard test. They want relief and eventually they will get it.

I did find that 200 dB wasn't too big of an exageration! The loudest sound=

"A peak of 100 kPa corresponds to a pressure amplitude of 70 kPa rms, which in turn corresponds to a sound level of 191 dB".

jjm525 said:

For a motorcycle it's a HUGE exageration. Think more along the lines of an atomic bomb....

I'm guessing a volcano blowing a mountain like Krakatoa into pebbles...

Most States already have laws that govern how loud any street-operated vehicle can be. These laws are mirrored by local ordinances. The simple fact is that it is a pain for law enforcement to try and address the issue, due to a lack of standard and testing guidelines.

Oklahoma law prescibes that it is illegal to make ANY modification to a vehicle's exhaust system that would cause it to be louder than was originally designed by the manufactuer. By the letter of the law, anything other than a stock muffler is illegal, however, this is seldom enforced, even less so with motorcycles.

Years ago I owned a Yamaha XT200 that was equipped with a White Bros. pipe and a Supertrapp with all ten plates. I had been riding it that was for close to a year, always with a full-face helmet. I went to take an entry physical for the military (rode it there) and showed signs of hearing loss. Prior to this I had exceptional hearing. Shortly after I switched to a stock exhaust equipped XL350R, no permanent damage done.

I have not read the article, but the AMA does not provide enforcement of the standard. The establishment of a standard would have to be approved and accepted, perhaps by the EPA, before it would have much effect. Still, 96dB is plenty enough for the street, though 2,000 RPM seems like a low number. Also, this process does not seem to take engine "load" into account. An engine freely reving does not seem to produce as much sound volume as one under load does. FWIW.

-Joe

Bill_P said:

Ever heard a pack of morons leaving Orange County Choppers?

jjm525 said:

Do you have data to back up that claim? Or did you make it up?

Made it up,,,

based on my experience in sound testing for MX and by what levels people find offensive driving past their homes or in the woods. 96 dB at 2k RPM, really 98 by the suggested standard, will easily be over 100 dB at mid RPM for most bikes, around 4500 RPM. Probably significantly higher not that it matters as the perceived sound is much greater than the small numerical dB increase suggests.

Take it to redline, as is often the case with those needing the attention, and breaking 110 dB would not be difficult to do. Build a pipe that passes this sound test AND is loud enough to keep the customers looking for loudness happy, hardly an engineering obstacle. Is it a stretch to state that just about any aftermarket exhaust would already pass this test? I don't think so.

By my guess, via experience, only fully open, straight piped, non muffled bikes would fail.

Do you think this standard would stem the actual excess noise/offensiveness the public complains about?