Noise testing of race bikes - what's the answer?

[codgyoleracer]

This has been a popular and subjective subject recently - and is one thats not going to disapear or be swept under the carpet anytime soon:

The rulebook is quite clear - however as many have commented at the track what are the parameters of the testing, the testing device / techniques and how do these affect the readings.

The tricky thing with noise - is that what the human ears "hears" is not always what the meter "reads"........

There has been a suggestion in another thread that static testing might be the go, - however the reality is that if an event is under-way and the local councils respond to a complaint, they will test the bikes ON TRACK. One bonus though of some sort of voluntary static test , is that it may well give us a guideline as to how close the bike is to the maximum limit.

Do we have any specialist acoustic people on KB that may be able to assist ?

[Deano]

This has been a popular and subjective subject recently - and is one thats not going to dissapera or be swept under the carpet anytime soon:

The rulebook is quite clear - however as many have commented at the track what are the parameters of the testing, the testing device / techniques and how do these affect the readings.

The tricky thing with noise - is that what the human ears "hears" is not always what the meter "reads"........

There has been a suggestion in another thread that static testing might be the go, - however the reality is that if an event is under-way and the local councils respond to a complaint, they will test the bikes ON TRACK. One bonus though of some sort of voluntary static test , is that it may well give us a guideline as to how lcose the bike is to the maximum limit.

Do we have any specialist acoustic people on KB that may be able to assist ?

hi glen, I am not a specialist in acoustics but have some knowledge, particularly from the testing side of things as I work for a council. One aspect of my job includes noise monitoring for compliance with district plans and new zealand standards. - also have some theoretical knowledge that may be of use. Having thought briefly about this topic since hd, (and in my morphine induced state) I wonder how the testing was undertaken, such as to what standard, location, consideration of background noise levels among other things. It seems odd that so many were reportedly over the relevant limits when I don't believe it was such an issue at the first three rounds despite testing ocurring.I would certainly be keen to learn of all the relevant facts (not simply kb speculation) and discuss further, not only for my own interest but also to assist racers in complying in the future to avoid further problems.

[Billy]

hi glen, I am not a specialist in acoustics but have some knowledge, particularly from the testing side of things as I work for a council. One aspect of my job includes noise monitoring for compliance with district plans and new zealand standards. - also have some theoretical knowledge that may be of use. Having thought briefly about this topic since hd, (and in my morphine induced state) I wonder how the testing was undertaken, such as to what standard, location, consideration of background noise levels among other things. It seems odd that so many were reportedly over the relevant limits when I don't believe it was such an issue at the first three rounds despite testing ocurring.I would certainly be keen to learn of all the relevant facts (not simply kb speculation) and discuss further, not only for my own interest but also to assist racers in complying in the future to avoid further problems.

I would be very keen to talk to you on this subject Deano,How can I contact you.

[White trash]

I would be very keen to talk to you on this subject Deano,How can I contact you.

Call Waikato Hospital would be your best bet Billy.

[Deano]

Call Waikato Hospital would be your best bet Billy.

Yeah I'll be here for a few more days yet and to be honest, my brain is a bit fuzzy at the moment what with the cocktail of painkillers I am on. Can you call in to see me in person billy ? I will get your number and call you soon.

[White trash]

If noise is tested on the front straight, you'll get vastly different readings on the same bike between Hampton Downs and other tracks due to the built up "valley" nature of that straight.

[malcy25]

Sure is a hard subject and one I know little or nothing about the technical aspect of it, but I can understand there are a huge range of influences to what reading will be recorded.

I guess it is one that some of us (ie the wider racing community) will get to know very well, fast....Hower, the bureacratic world this leads into is another whole realm again...

I know one of the families bikes is super aggressive while warming it up (like a certain fail on static test), but ride by is no issues...

I saw one recent comment offshore which alluded to the fact that to ensure bikes complied with noise limits it would be expected that the riders should be looking at areas that produced noise in addition to the exhaust (chain and intake are two areas)

[Kiwi Graham:Me]

Good thread topic Glen and thanks for your call last night Deano (oh and wish you a quick recovery mate). Glen is right this issue isnt going to go away, its only going to get more stringent.

Good on you Deano for offering to help Billy, we need to be seen to be doing right by the noise issue and being pro-active is the way to go.
Ask any engine tuner and they will tell you that you dont need noise to make power, in saying that though how bloody loud are the works GP bikes!!

Stamped on the frames of all NZ legit imported bikes will be a DBa reading and nearly all exceed the 95 DBa cut off, I believe this reading is taken statically at a fixed rev limit and often why production bikes have a 'hole' in power curve at this pre-determined rev limit allowing them to gain compliance.
You would think this test would pick up alot of mechanical engine noise.

On the track the main cause of the noise breach appears to come from the exhaust note and this is the obvious area to look at first. I believe several bike got under the limit at the classic festival with modifications to their exhausts so it is achievable.

[Paul in NZ]

http://www.youtube.com/watch?v=2KdYUhH3JSo

http://eur-lex.europa.eu/LexUriServ/...78L1015:en:NOT

http://www.unece.org/fileadmin/DAM/t...-R41WG-06e.pdf

[nodrog:Me]

http://www.fim-live.com/fileadmin/al...04_Anglais.pdf

107db limit, with a 3db tolerance after the race.

"Noise test must take place in a clear area adjacent to the Technical control at least
5 metres from any possible noise reflecting obstruction."

page 137 has more technical shit on how they measure, i cant be arsed typing it all out.

[steveyb]

There are acoustics science experts in New Zealand, some of whom are at Industrial Research Ltd in Lower Hutt. The reason I mention this is that the government has a programme whereby entities (businesses, individuals, etc) who have a technical problem can seek funding to engage an expert to help with their problem.

I can see that this issue would be well served by having expert input into the technicalities, the difficulties and the establishment of a best practice technique for testing.

Now, it might also be reinventing the wheel, and indeed we may well already be practicing best practice.

It might be the case that different environments are going to produce different results for the same individual with regard to a standard testing approach, it would not be the first time that has happened.

The decibel can be a rather troublesome unit to pin down because it is not absolute, it is relative and is not a measure of sound or noise, but a unit of power, or in the case of sound, of intensity and is also used in electronics. The dB also has a logarithmic scale, therefore each increase in 1 dB makes the intesity 10 times higher. The dB scale is set up relative to least intense sound a human ear can hear, apparently the sound of a mosquito flying at a distance of 3m (20 micropascals (μPa) = 2×10−5 Pa) where one Pascal is equal to 94 dB(SPL).

So, if MNZ wishes to investigate this further to see if we are indeed already in best practice, or if there is room for improvement, I would be happy to help out as I do know some of the acoustics guys at IRL.

Billy, if you want to discuss, we can catch up at Taupo.

Steve

[Deano]

I have a contact at massey university in wgtn. He was my lecturer and someone I also went to for advice once commencing work. Professor philip dickinson. He is a leading authority on environmental acoustics and is semi retired. His hourly rate was a tad over one third of the fee of others I know.

[Billy]

Call Waikato Hospital would be your best bet Billy.

Thanks,

Deano has been in touch and we will talk more when the drugs wear off (His not mine haha!)

[CHOPPA]

The measuring of sound, sounds like a very complex science. It doesnt seem like the sort of thing an unqualified person can just stand on the side of a race track when 20 bikes are whizzing around, generators and PA systems are buzzing away then say oh that bike is going to be black flagged.

I cant imagine any appeal court would hold up a judgement to exclude any rider but if they were black flagged mid race then that could really cause an upset.....

This thread should get interesting haha

[quickbuck]

... apparently the sound of a mosquito flying at a distance of 3m (20 micropascals (μPa) = 2×10−5 Pa) where one Pascal is equal to 94 dB(SPL).

Now that would be Fly Past I would Love to see....

Oh, you mean the insect... As you were.