Noise Problem: The AMA is a bunch of morons

[Tony Eeds]

There is no advantage.

I will see if I can get Chris to join up and comment on this thread.

You missed the point that the tests PREDATE the advent of the modern four stroke.

The sound carries farther simply because it is a lower frequency sound. Why do you think fog horns are so low in pitch?

Most modern machines come with a pipe that will meet the 96 dBA spec, but after 20 hours of use degrade to be in the 99 to 100 dBA range.

You are leaving out a huge number of variables that are part of the overall sound footprint of a bike as well.

 

[SpeedyManiac]

I know the tests predates the modern four stroke, but what I'm saying is from what I can tell, the four strokes have an advantage of testing lower than their true sound level and that the test should be changed.

I know that lower frequency sounds carry farther, but I'm addressing a very specific issue that in terms of absolute sound pressure levels, using the dBA scale gives four-strokes a slight advantage, and if they went to using the dBC scale, it would level the playing field, so to speak.

I know there are many variables in sound testing, but all I'm saying is that the scale they are currently using is the wrong one for sound testing motorcycles and using a frequency neutral scale would help put all bikes on a level playing field.

 

[thorman75]

I remember years back something about noise and the AMA, Wardy was involved and 1 test involved a stock CR500 Honda.If you know CR500's the stock silencer is 2 stage and huge, but the bike still failed the noise test. The culprit was from air rushing into the intake/airbox. Go figure.
i'm sure Ger remembers

 

[Tony Eeds]

I know that lower frequency sounds carry farther, but I'm addressing a very specific issue that in terms of absolute sound pressure levels, using the dBA scale gives four-strokes a slight advantage, and if they went to using the dBC scale, it would level the playing field, so to speak.

All sound can be described as fitting on a curve that generally describes a bell. C range is a wider range of sound than A range, but A range replicates and weights the range to more closely match the range of human hearing. C picks up a portion of the high range as well as the low range, so any ring-a-ding will set off the meter as well as the 4 stroke you are wringing your hands about. C range is wide enough to be impractical according to Chris. As I said, his partner derived the criteria and wrote the rule. Additionally, he has a PhD in acoustics assuming my CRS isn't getting to me. Sure the 4 stroke sounds louder, and the sound carries farther, but that is a result of exhaust velocity, frequency, and many more variables that make the discussion rather mute.

I just had the class last week and have a years worth of acoustics in school myself.

Post up your charts and I will get Chris to look at them. ;)

 

[Tony Eeds]

I remember years back something about noise and the AMA, Wardy was involved and 1 test involved a stock CR500 Honda.If you know CR500's the stock silencer is 2 stage and huge, but the bike still failed the noise test. The culprit was from air rushing into the intake/airbox. Go figure.
i'm sure Ger remembers

Straight from my notes ...

Exhaust note ---------------- 90 dBA
------------------------------------ 92.5 dBA
Inlet Sound ----------------- 89 dBA
------------------------------------ 93.2 dBA
Fin Radiation --------------- 85 dBA
------------------------------------ 93.8 dBA
Exhaust Can Radiation ------- 85 dBA
------------------------------------ 94.0 dBA
Chain Rattle ---------------- 80 dBA
------------------------------------ 94.1 dBA
Tire Noise ------------------ 78 dBA
------------------------------------ we didn't compute this one
Internal Gear Noise --------- 77 dBA

You make a great point, although the accumulative affect is small.

We also learned how to catch cheaters! :p

 

[SpeedyManiac]

Thanks for the explanation Tony. I'm relatively new to acoustics stuff, I just thought I found something of interest that could maybe help keep riding areas open. I'll post the charts as soon as I get copies from my prof.

 

[Tony Eeds]

Thanks for the explanation Tony. I'm relatively new to acoustics stuff, I just thought I found something of interest that could maybe help keep riding areas open. I'll post the charts as soon as I get copies from my prof.

Speedy:

I would never want to shoot you down, or diminish your enthusiasm for helping the sport. Please accept my sincere apology, if it feels that way. Frankly, we need all the help we can get and the younger you get involved, the longer you can be part of the solution.

I told a very good friend, when I agreed to be on the Board of Directors of the Texas Motorized Trails Coalition, that I was going to serve on the board because we are standing on the shoulders of giants. Giants that have given us the reigns of the greatest sport on earth. It is time for me to give back.

That was a little over a year ago. Now, I am the apparent incoming President of TMTC. I say apparent, as it does not appear that anyone will be running against me. I am a NOHVCC representative for Texas and am wrapping up the master plan for TMTC's newest off road park, Escondito Draw Recreational Area.

I noticed a preponderance of grey hair at the NOHVCC conference last week. Jump on in, the water is fine and we would love to have you!

Politically, now my hand are a bit tied regarding the AMA, but trust me, I am learning whom to call within the organization.

 

[RYDMOTO]

The one thing to understand is low frequencies do travel further than higher frequencies.It's interesting to note that elephant calls are in the sub-frequencies and their call can be heard 20 miles away.And those same sounds can carry thru vegatation as those sound waves are in the 20 foot range.Not sure how low our four strokes go so there should be a concern that way.

 

[Patman]

Did any of you guys actually read and understand my original post? Or am I just talking to myself?

Gee since you didn't specify that the discussions could only go in the direction you specifically wanted them to I sort of figured the dynamic flow of the posts was what made DRN, DRN. Next time post up about 12 pages of small print being specific in what you demand in any replys :laugh:

 

[Racesmith]

I can't believe I read this whole thread...I should receive my acoustics degree in two to three weeks right???

 

[thorman75]

If you want real noise, try standing next to a 175 Howitzer, although I guess the navy's guns are louder yet as they're bigger.

 

[BadgerMan]

Loud pipes save lives.

One of the dumbest quotes ever......... :|

 

[Tony Eeds]

If you want real noise, try standing next to a 175 Howitzer, although I guess the navy's guns are louder yet as they're bigger.

Yup, I was in armor in the Army. It takes a lot of sound to make me jump.

I assume the big guns of the battleships of old could really make a noise. Everytime I tour the Battleship Texas they show us the floor that cracked when the guns fired parallel to the length of the ship while chasing a Jap ship during WW II. They usually fire perpendicular to the length of the ship to absorb recoil.

I would assume anything that can throw 3 tons in excess of 20 miles can make all the sound it wants.

 

[Tony Eeds]

I can't believe I read this whole thread...I should receive my acoustics degree in two to three weeks right???

Nope!

You have not turned the research paper and I don't ever remember seeing you in class before today!

:)

 

[Patman]

That's not really fair Patman. I ride a HD which is posted somewhere on here and a CRF450. The 450 is louder than the HD, so are you saying that I am trying to draw attention to myself when on the track. If you knew me you would know I putt around and never, on either bike, need to draw attention to myself. I am sure you don't mean all HD people are this way just the ones you work with. :p

If its got two wheels I like to ride it. It is great time spent together with my son and the best stress relief you can find. When was the last time you saw a Harley parked in front of a Pschiatrist (sp?) office. :laugh:

Is it not fair because it holds some truth or because your Harley has stock pipes? Don't misunderstand my intent, which is the silly "loud pipes" excuse because if that was true every vehicle would be safer with an open/loud exhaust. Also don't mistake that the bikes I refer to are ridden on public streets and not a track situation which is completly different.

It has also been my experience that not only the guys I work with have a self esteem issue but 99% of the other persons I have met that have a loud street exhaust also exhibit some need for attention. I guess also it's not so much seeing a HD at a head shrinkers office as it is them realizing perhaps they have an issue and might need to see one. IMHO most are so self absorbed that it would never cross their mind. :laugh:

Riding is for sure a great thing and helps release stress but I believe it should be done in a responsible manner. There are plenty of other idiots on bikes as well doing stunts and riding in an unsafe manner who I do not appriciate either.

Let's also not have any misunderstanding that my personal bike is not stealth. A stock XR250 is very quiet and I honestly wouldn't mind having that level of sound if I could maintain the same level of performance it has but, my bike was built/modified for a specific type of riding and the engine Rich built me needs a different exhaust. The exhaust was custom made by Thunder Alley and is louder than stock no doubt but when Bob gave me the option to send in the tail section for an updated "quiet core" I jumped on it! It has made no difference in my calibrated seat of the pants testing and he assured me it meets the Cali dB requirements for off road riding on public lands even with my modified engine. I also happened to insist on any exhaust I installed having a Kritzman spark arrestor which the TA system did from day one. Why? Responsible fun. I shouldn't risk starting a fire just because I "need" some uncorked exhaust on my off-road bike.

Patman is jealous he doesn't have a Harley,...

Busted :laugh: .....NOT! The idea has never even crossed my mind, honestly!

 

[BadgerMan]

The one thing to understand is low frequencies do travel further than higher frequencies.It's interesting to note that elephant calls are in the sub-frequencies and their call can be heard 20 miles away.And those same sounds can carry thru vegatation as those sound waves are in the 20 foot range.Not sure how low our four strokes go so there should be a concern that way.

I find it interesting that you would liken a four stroke dirt bike to an elephant...... :rotfl:

 

[DougRoost]

I had the same reaction since I hadn't thought of that. The 250f's at SX sound like a bunch of farts to me :)

 

[CRASH39]

I don't know. to me its and excuse to keep pointing the finger at the dirt bike or atv wether it is 2 stroke or 4. I get this one guy who hits it hard with is mote carlo ( a 85 it looks like ) flying down the road ( have to admit, it is a pretty sight ) like no one uses it but him.........wich I don't mind cause it takes the focus off of me. After all the only one who complains anyway is the neighbor from Chicago, ILL. But I gess we who ride are the outlaws instead of a 500wt wanna be drug car with rattling doors and trunk that booms for a mile...

we need a quiter machine, anyone have a electric dirt bike? :laugh:

 

[thorman75]

One of the dumbest quotes ever......... :|

Do you ride on the street? And I'm not talking about a gravel road, more like 80/94 Borman Expressway at around 4pm on a weekday. Then and only then could you make an honest accessment.
I know from EXPERIENCE when I was rear ended on that same road on a full dress H-D, why did she hit me, "I didn't see you" was her reason.
But thats all, I'm done, you do what you want, believe what you want to,I'll do the same.

 

[Offroadr]

OK boys and girls keep the thread on topic. This is about the AMA and noise regulations not a thread on stereotyping

 

[RYDMOTO]

What I was trying to say is loud elephants save lives. :nener:

 

[HubertGarfunkleIII]

so uhhh 4 strokes are louder than 2 strokes?

 

[kmccune]

I had the same reaction since I hadn't thought of that. The 250f's at SX sound like a bunch of farts to me :)

OK I know I'm contributing to the hijacking of this thread, but I couldn't pass this one up. That is exactly what I think they sound like too. It make my wife angry when I say it because she says that they sound mean or tuff...yup just like a fart :laugh:

 

[Mr.Sloth85]

OK I know I'm contributing to the hijacking of this thread, but I couldn't pass this one up. That is exactly what I think they sound like too. It make my wife angry when I say it because she says that they sound mean or tuff...yup just like a fart :laugh:

I agree with your wife on this one, id rather have a fart then a weed whacker as a dirt bike. :nod:
sorry hi-jack contributor :whoa:

 

[Patman]

Yes all threads must remain on topic (whatever that is). Pay no attention to that man behind the curtain. LOL!