IMPBA noise rule & dB meters

[Mike McKnight]

Guys the NAMBA rule is 92db and we in District 9 even have one pond that we are limited to 90db. Lucky for us that pond has really high banks and levees that a good portion of the sound is absorbed or deflected by the ground and vegetation.

I have never personally witnessed anyone DQ'd for noice violations although there very well could have been a candidate or two including myself at one point or another. It seems though that monitoring and enforcement seems to go in cycles. Usually when there is one very obvious violator then monitoring becomes more intensive and there are a few people that get warned and everything is fine for a while so monitoring gets more relaxed.

As one who has some experience with professional PA systems and db, spl and a number of other instruments for measuring and generating sound levels. I know several manufacturers that make units in the $79-$250 range that assure me that they are all within +/- less than 1db accurate in the 90 to 100db range. These are the units that are most commonly used by OSHA and are the ideal units for our application for needing a "Spot Check" or "Snapshot" reading.

May I offer one simple piece of advise? Do not use a Radio Shack meter. It is junk for lack of better word. RS is good for some things but not for that. We had two of those RS meters in this District and luckily one has been lost and the other analog one is not working right anyway. I have used one that I borrowed from a friend of mine that still works as a sound engineer. Now his has a few more bells and whistles than the one I have since his has to be NIST (National Institute of Standards and Technology) certified, but his and my $200 one were pretty darn even. Both are different manufacturers and had been calibrated within 3 months of each other. By the way calibration is need only once a year and should only be done by the manufacturer or a NIST certified lab. They will give you the documentation you need and will place tamper tape on the unit to certify it. It's not that much costwise....you should make it an annual budget item.

Unless you are an engineer or someone NIST certified do NOT try to calibrate this equipment yourself. Most manufacturers are certified especially if they are making or selling equipment used by OSHA or law enforcement. Whatever you do, document everything epecially calibration records.

 

[Wesleys Custom RC]

I was at the IMPBA nats and I was sittind beside the meters most of the week and I made a fiew observations that I think were worth discussing:

1. The biggest suprise to me was the noise level of the small boats. Many of the 20 monos and riggers had no muffling and I'm sure it was because they thought (as well as I) that the smaller motors put out less noise. WRONG! I guess we don't precieve higher pitched noise the same as lower pitched noise. The DB meter does not discern between the 2, only volume. Maby that's why many of us loose hearing in the higher ranges first. On a similar note, one of the fast electrics gave a reading of 84 which really suprised me. I am loosing my hearing in the high frequincy range so I guess it stands to reason that it did not sound loud to me. It sounded like a quiet turbine jet when it went by.

2. 2 meters were side by side all week. 1 usually read around 1 db higher than the other and I don't think anyone was ever warned unless both meters gave a reading higher than 92. They tried to be as fair as possible with everyone and I personally never saw a boat over 92 db that had a REAL muffleing device (not drilled out) atached to it.

3. I do believe 92 db is a good bench mark you could not cary on a conversation beside someone when a boat over 92 db went by. normally if I was interupted by a passing boat, then I went over to the meter and viewed a high number.

Those were my observations for what they are worth.

 

[lohring]

A few years ago my club ran extensive tests on a gas mono, at that time the noisiest class, before suggesting a noise rule for NAMBA District 8. This is similar to what the IMPBA is using, but with the provision that the measurement is taken about 50 feet from the boat and that the limit is 90 dB. We found that the combination of a simple stinger muffler with water injection added to the M&D pipe not only was quieter than this limit, but was actually faster on radar. The only boats that have had problems meeting this limit are stock outboards, especially the larger ones. They are currently exempt. Almost all nitro boats with standard muffling are below 90dB.

We found that the most sensitive part of the measurement is the angle of the meter to the exhaust. The distance to the boat was nowhere as critical. The readings will be louder when the exhaust is even slightly toward the meter. Running the boat straight, exhaust deflectors, and meter alignment are important. We placed the meter on a tripod to help. However, as I stated above, most muffled nitro boats in our area are well below 90 dB so these details are not too important for them.

NAMBA's rule measures the sound 50 feet from the pond edge. Almost any boat, even those without mufflers, will meet this rule. I have been at a NAMBA sanctioned race where the police nearly closed the event due to noise complaints. I'm sorry that Rod was disqualified, but there is no performance advantage to noisy boats. We all love the sound, but others don't.

Lohring Miller

PS During some dyno testing I measured sound levels of over 110 dB close to the engine. We all wore hearing protection, but this is what an unmuffled 25cc gas engine can produce. Even in industrial areas this could get you a noise citation from the police.

 

[Geraghty]

Here's a question- NAMBA has had a dB rule in place for YEARS, how it that rule being "policed" ... or is it?? :blink:

RE:NAMBA

I raced NAMBA/APBA for years before racing IMPBA when I moved to Wisconsin.

I don't ever remember seeing a DB meter at a NAMBA race.

As I recall 99% of the all nitro pipes being run had a Prather add-on silencer.They definetly reduce that exhaust report "crack" I mentioned earlier.

The loudest classes in NAMBA were the stock outboards being exhausted through the K&B lower units.

There wasn't much we could do with them so everybody kinda looked the other way.

As I recall all in all the noise of a NAMBA contest was less annoying.But hell ,I'm getting older so who knows what I remember.

 

[DON MAHER]

Guys,

Here in NAMBA Dis. 19 we have been fairly lax on

the noise issue in the past, due in part to the fact that most of our sites are away from any home or bisness area's. We are going to have to change this way of doing thing's or we will be on the outside looking in at this great hobby. Inforcement of the noise level is second only to safety in importance regarding our hobby. I am looking & lisening to see what may help do this here in Dis. 19. I hope everone else will do the same.

One thing I have noticed is in Dis 19 we have a "three strike's your out" policey, Round 1 "You are over by 5 db's, get it down!" Round 2 "You are still over by 2 db's get down to or below the limit by Round 3 or you are out!!" I think the "two strike"policey is a little harsh especialey at a special event such as a national's. Just my $ .02

Don

 

[Geraghty]

I don't know the actual percentages, but there hundreds of boats that were legal and ran at the Regatta. We have identified problem areas and will move quickly to find solutions. Until then we need to use the rules that everyone voted upon and work towards a resolution.

I thank everyone for their compliance

at Evansville and rush to fix during the event,

John Equi

IMPBA Technical

John,

I think this is where you and I will have to agree to disagree.

I agree the current rules is all we have,but the current rules proved their worth this last week in Evansville.They are definitely flawed,and that is being kind.Just saying we have to use what is there because it is there is ,in my opinion,just plain wrong.

I don't believe we should suspend the current rule but I do believe the current rules will have to be enforced with some thoughtful "discretion" until we all get a handle on all this.If somebody has obviously made a legitimate attempt to comply and they are still questionable,then they should still be allowed to run.Probably 20 people could have been DQ'd this last week if the current rule was followed to the letter.That would have served no one.

I just spent 11 days listening to "all" the boats in Evansville. I was definitely an interested party.

I agree that there were several boats that appeared to comply with the current rules.With that being said and with what I observed that was as much if not more,just plain luck as it was muffling expertise.I observed several boats running exacty the same pipes and their noise numbers were all over the spectrum.I also observed "quiet pipes " with add-on mufflers that would not pass.Why is this????

I don't think we know yet the right questions to ask.

If you personally had measured my boat with your meter I would have been at under 90DB and allowed to race.

The published rules should never intentionally send a racer on a 14 hour drive to an unknown abyss of flawed rules.Junk rules voted in with all good intentions in mind are still "junk".

Rod

 

[Ron Olson]

What I still say is that someday it could come down to a noise complaint from someone in the neighborhood who gets pissed off from the noise from a boat race and call the police. They couldn't give a rat's ass about our 92 dB rule if we're ruining someone's Sunday. Local noise ordinance's would over-rule the IMPBA dB (or NAMBA for that matter) rules and shut down a race.

The site itself can make a difference. One pond that I practice at reflects the sound badly while others don't.

 

[waltr]

I spoke to the official from Berlin Raceway in Grand Rapids Michigan over lunch.

Really no help there. He uses a Radio Shack meter also.

The're also supposed to stay under 92db.A warning is given to the over 92 crowd but no enforcement till they hit 100db. :huh:

 

[Geraghty]

Somebody here interested in this issue sent me an e-mail from the Netherlands, I believe.

It was titled....."Evansville".

It was sitting in a spam folder and.....Well old dumb thumb here accidentally deleted it before I read it.

Whoever that was ,would you please re-send it to [email protected] and I will respond....I promise.

 

[DaveMarles]

Maybe I can help and I hope I'm not treading on toes but I will be blunt...... I was racing boats when we had the big push to get noise levels down in the late 70's in Europe. We went through exactly the same teething troubles as you seem to be experiencing and my answers are these... Complaining about the noise meters and the wind direction etc is fine but the answer is not in the noise measurement or calibration or who operates the meters.. The answer is to make the boats quieter. Its not rocket science. 92db is LOUD, LOUD, LOUD. (thats for those who are hard of hearing due to unmuffled pipes ) Firstly the idea that in Europe we use low nitro and so we don't have the same problems. Forget it. Just like the USA we have guys who live, breath and sleep high performance boat engines and high nitro is used and in actual fact I don't think it makes any difference whatsoever. Noise is noise whether its caused by a hard running engine or a rubber mount thats too hard or a useless silencer. Here, we have to be under the noise limit or we go home.

Regarding pipes..In general the quiet pipes in the US are not quiet, they are quieter than an unmuffled pipe but thats all. If people think that exiting from the stinger into a chamber and out of another stinger is good enough then I can tell you that unfortunately they are kidding themselves. Its an easy manufacturing solution but just not good enough. It really shouldnt be difficult to make something that will work OK and please lets not hear the calls of "This is useless because I can't hear my engine its too quiet" or " its killing the performance of the engine". I'm sorry,they are just excuses and can be added to all the others, I could make a list but it would be a long one. If you are a good fast racer then you can be a good fast racer with a quiet boat too.

Back to some facts. Exhaust noise is only a part of the noise equation. Induction noise plays a big part and on the the bigger nitro engines and gas boats, engines or at least the carbs must be covered. Noise transmitted through the hull is again another problem, hard engine rubbers make that worse, try softer mounting rubbers with cups around them for example, Monos can have padding in the sides or thin foam insulation. Like I said, no rocket science.

Wooden riggers are reasonably quiet anyway but the uncowled engine is a big problem there,the noise transmission from the crankcase itself is added into the equation and of course the bigger problem could be the drivers who like the noise anyway which uncovers another major problem. Noisy boats sound faster.

Its not all perfect, I've been warned for noise and been DQ'd too but I don't argue I just reduce the noise from the boat. My monos have most of the pipe cowled and the motor cowled too with big air scoops built into the boat. If the motor cowling is not close fitting then the noise level increases. Solutions are not that difficult.

I operated the noise meters too and DQ 'd plenty but eventually people stopped arguing and devoted their energies to what was important.

Incidentally, the noise rules are relaxed for Naviga World Champs (although I'm sure it would be denied) or many riggers wouldnt be running.

Dave

 

[Chris Wood]

I just have one thing on this topic since i was in the middle of the mess this last week.. How do the people pass such a rule when there are only 2 manufacture's that make pipes's and PARTICAPATE in races. Notice i said PARTICAPATE.. i didn't see ops, mac' products, ect ect there.. I understand why, and how the relivance of this play's out. But, the only PIPE MFG at the nats was STEVE COOPER OF COOPER PIPE'S.. and Jim Irwin of Irwin pips. And steve and jim do care and are working hard to get this right..

I understand that 20 outboards, mono's and 40 ect ect will pass GENERALLY ( sorry rod ) but when it comes to big motors 67 80 90 1" and so on. the are loud to begin with.. LOT's of RPM.. That is the big discussion that we are talking about. . I know i was right in the middle of it all lol...

Rod is right.. don't get rid of the rule but ADDRESS IT BEFORE WE LOOSE GOOD PEOPLE.. it is apparent that the readings of DB'S will not work at all ponds.. MY QUESTION is why don't we get the MFG involved. To my knowledge when the rule was passed nobody approched any mfg's and asked IS THIS POSSIBLE AND WITH GOOD PERFORMANCE.

Dave i understand what you are saying where you live.. Here is my position i posed this week.. If you are at the limit and the boat is 10 plus mph slower you become a moving bouy and people get mad.. ( get out of the road you are causing problems ) trust me i have seen and hear others say that before..

Where do we go from here.. The IMPBA needs to get all and anyone that is involved in the and have a disscussion..

Steve cooper went to the board meeting thur night.. they asked him to go.. From what i hear they never once ask him to say anything and wasn't invited in to the closed setion when this was brought up... Man WHAT A GOOD IMPRESSION....

make's it hard to fix it when you can't be heard.....

chris

 

[Brian MAhoney]

Its funny, feel like I've read all this before, there is no need for quiet to mean slow.

From what I have read the likes of Chris can put his mind to the set-up of a rigger and fine tune that and the prop to get a fast boat that handles. Apply the same methodical approach to noise and you can run the same speeds at 92 db, 90 db, 85 db or 80 db. It's not going to be easy for those of you who lead but you can run just a fast and keep your lakes. You may even find you get more enjoyment from a days racing.

Listen to the likes of Dave and should be able to shortcut the learning curve.

Brian

Dave i understand what you are saying where you live.. Here is my position i posed this week.. If you are at the limit and the boat is 10 plus mph slower you become a moving bouy and people get mad.. ( get out of the road you are causing problems ) trust me i have seen and hear others say that before..

Where do we go from here.. The IMPBA needs to get all and anyone that is involved in the and have a disscussion..

Steve cooper went to the board meeting thur night.. they asked him to go.. From what i hear they never once ask him to say anything and wasn't invited in to the closed setion when this was brought up... Man WHAT A GOOD IMPRESSION....

make's it hard to fix it when you can't be heard.....

chris

 

[piper_chuck]

This is a bit off topic, but sports fans may get a kick out of it: http://fayettevillenc.com/article?id=235349

 

[Scott Norris]

I don't want to hit on a sore spot or anything here but............... if we could run lower nitro content and still be competitive and be quiet, wouldn't it be better for the Nitro end of boat racing also? Reducing the fuel costs might bring more newcomers into the hobby and maybe it would be easier to finish heats and make engines last longer.

OK now ya'll go ahead and Tounge Lash me.

 

[Joe_Knesek]

A stationary measurement like the AMA uses makes sense to me. It would ensure that all boats are measured in the same manner and would reduce the gray area. I cut the link below from the AMA rule book. It is worth reading.

 

"All motorcycles must meet sound limits of 102 dB/A measured on the

​

"A" scale at 0.5 meters (20 inches). Test procedure will be prescribed by

​

the AMA, in accordance with SAEJ1287."

http://www.ama-cycle.org/legisltn/soundbook.pdf

​

 

[Piston1]

Incidentally, the noise rules are relaxed for Naviga World Champs (although I'm sure it would be denied) or many riggers wouldnt be running.

Dave

Mr. Marles, correct me if I am wrong but this statement implies that you guys are moving in this direction. Whats the purpose here.

Jose Ortiz

 

[Grimracer]

Its likely that this will go on for years and years.. that is untill we get the MFGs involved...

Look at ROAR or IFMAR.. .. no need to reinvent the wheel..

Grimracer

 

[Don Ferrette]

A stationary measurement like the AMA uses makes sense to me. It would ensure that all boats are measured in the same manner and would reduce the gray area. I cut the link below from the AMA rule book. It is worth reading.

 

All motorcycles must meet sound limits of 102 dB/A measured on the

​

"A" scale at 0.5 meters (20 inches). Test procedure will be prescribed by

​

the AMA, in accordance with SAEJ1287.

 

http://www.ama-cycle.org/legisltn/soundbook.pdf

​

Funny you should mention stationary testing. I've been giving this situation ALOT of thought & the 2 biggest problems I see right now are-

1- we've got dB meters not reading the same. This has become painfully apparent with the posts here & the people I've talked to who were there.

2- there is too much potential variance in the measurement distance & course acoustics. Yes the rule states 25 feet from the shoreline BUT we specify in the rulebook a 50 to 150 foot range from shoreline to the line between buoy #1 & #6. So you can be measuring as close as say 40 or 50 feet (if the boat runs wide) or as far as 175 feet which can change your reading and depending on the course's acoustics this could vary a good bit as some sites are way more forgiving than others.

So first I think we all concur these meters need to be calibrated to read the same. Based on what John Equi is working on this is already in motion to being addressed. Now back to the idea of stationary testing, this REALLY intrigues me. Consider for a moment what this does, it eliminates all pond variables! Distance from meter to running lanes, reflective nature of the site, etc. all become moot. Granted we will have to do some serious testing to determine what the added amount dB wise will be needed when you measure a boat say 3 feet straight behind it vs. on the water to get to the equivelent 92dB but this benchmark can be created. And the tech test would short and simple- you place you boat on the designated stand, fire it up, one guy watches the meter & one guy watches you pull the trigger wide open a couple times & you're done. You could even take it further making it discretionary as it's not rocket science to hear a boat that seems loud. The CD of the event simply says we need to sound check your boat between heats & tests the suspect boat. Even without testing all boats (at a national level event I would say test all as part of tech inspection) if this type of test were in place I feel strongly it would be a great deterrent knowing you could be subject to a standardized test at any time plus it's a test you could duplicate in your own backyard!

So any thoughts on this?

 

[Chris Wood]

Its funny, feel like I've read all this before, there is no need for quiet to mean slow.

From what I have read the likes of Chris can put his mind to the set-up of a rigger and fine tune that and the prop to get a fast boat that handles. Apply the same methodical approach to noise and you can run the same speeds at 92 db, 90 db, 85 db or 80 db. It's not going to be easy for those of you who lead but you can run just a fast and keep your lakes. You may even find you get more enjoyment from a days racing.

Listen to the likes of Dave and should be able to shortcut the learning curve.

Brian

Brian,

I have no problem with running fast and quiet.. it would be rather cool.. just show me a pipe that will get me there.. anyone??? i am all for trying new things.. ask steve cooper.. he is working on some new stuff for us to try.. but in the mean time until we get it figured out what can i use.. that is my question.

chris

 

[AWaddle322]

Don, the problem I see with stationary testing is that the motor may be rich and may not reach full rpm. I had put some thought into this and it makes since that a motor that is not loaded will not be working as hard a make as much noise.

Also with the Evansville pond being rock throwing distance to the interstate the back ground noise changes alot. I reaaly believe the board of IMPBA SHOULD GIVE SOME DISCTETION TO THE HOST CLUB until we learn more about qll of this.

Allen