dB readings

Well I just got done reading Mr. John Equi's "technically speaking" in the December Roostertail. All I can say is that I'm stunned at the "instructions" given on how to take noise readings & it was written as follows-

"Our existing wording, as well as the revised rule Russ proposes takes the readings at 90 degrees to the travel lane with the boat in front of the sound meter. I did have to practice a bit to catch the boat in front of me. If readings are taken between buoy #6 and the starting line, they should be easier to obtain, since the boat stinger will never point directly at the meter. Using the existing rule could produce an errant peak reading that is outside the described detection area if the operator waits till the boat enters turn 1 and observes the meter."

John, I'm sorry but what the #*@$??? Taking readings BEFORE the boat gets to the meter? I have been studying dB readings on these boats regularly now for a number of years & these "instructions" given will only serve to help cushion the reading of an illegally loud boat. The point of a noise rule is to REDUCE the noise output in general, not just on certain parts of the course. It doesn't take a genius to know that the loudest readings will occur when the boat is at & going away from you. There are no "errant peaks" as a dB reading is SOUND PRESSURE & the highest reading will be when that SOUND PRESSURE is coming at you, in this case when the boats are at & going away from you. It also is not cumulative, it will read the loudest noise source no matter if it's one or three boats go by at the same time. The current method of the meter pointing straight out at the course & observing the highest reading as the boats pass along the front of the course is the correct method.

And BTW- this is the second consecutive issue of the Roostertail where you are using your column of "technically speaking" to attempt to influence the way a member votes or may vote on an upcoming issue. Technical articles are great but please keep it to "the facts" & not personal opinion or points of influence. Using the Roostertail as a medium to campaign your own opinion or feeling is not fair to anyone who might have an opposing view as they do not have the same advantage & leverage your column affords you.

This might ruffle feathers & I mean you no disrespect John but this is just not right.

Don first off Equi is not using the technically speaking section to influence the noise issue. He is just stating his findings from the readings he has taken and the way the readings were taken. As for how the readings were taken. It was found out that when readings were taken on the left side of the Drivers stand the stand blocked the person view of boats approaching the DB reading area 90 degrees to the lane of travel. Ther efore you may be getting some residual readings from boats geting luanched as you are trying to catch a reading on a boat already up and running. But, if you take the reading on the right side of the drivers stand you have a clear view of which boats are approaching the reading area. That is why he suggested taking readings on the rightside of the driver stand. It is a practical reason making attaining the db reading easier and more consitistant.

bzubee said:

Don first off Equi is not using the technically speaking section to influence the noise issue. He is just stating his findings from the readings he has taken and the way the readings were taken. As for how the readings were taken. It was found out that when readings were taken on the left side of the Drivers stand the stand blocked the person view of boats approaching the DB reading area 90 degrees to the lane of travel. Ther efore you may be getting some residual readings from boats geting luanched as you are trying to catch a reading on a boat already up and running. But, if you take the reading on the right side of the drivers stand you have a clear view of which boats are approaching the reading area. That is why he suggested taking readings on the rightside of the driver stand. It is a practical reason making attaining the db reading easier and more consitistant.

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Bill I don't want to get into a slugfest over this but go back in the Sept. issue John wrote this countering Mark W's proposal he had just submitted-

"......and already we have a Discussion Item submitted as a proposal to lower the figure to 92db! If the limit was set at 92db for this Regatta, only 9 hulls would be illegal. Lets let the existing rule run for a while, continue our experimentation, and maybe move the limit lower in a year or two."

And from December issue-

"I was a bit surprised when Russ Williamson submitted this rule as fast as he did. I was expecting IMPBA to run with the original noise rule for a few years before changing it to a lower limit as we anticipated. Russ attended the Regatta in Jackson and was ready to jump in with a new proposal a month or so later. I have personally observed that 95% of the Regatta were below the 92db and many below 90db, when readings were taken at the left of the drivers stand."

This is his opinion and especially the Sept. comment an effort to influence, nothing technical here.

I'm all for consitant readings & it's been discussed many times that you should take readings once all boats are in the water so as not to be influenced by pit noise, that is common sense. What you're saying about taking readings is NOT what John said. He is clearly saying to take readings between bouy #6 & the starting line which is BEFORE the boats pass you. This will absolutely affect any readings you take & will not be true peak readings. How on earth can you get an accurate reading of SOUND PRESSURE when the source of the pressure is not yet facing the measuring device. Come on, quit trying to gray this one over too. <_<

And BTW- if 95% of the boats at the Internats were UNDER 92dB as he stated, why would he not support going lower if it is clear MOST of the boats are already there. I like John but this has really disappointed me.

I would like to know why the 3.5 needs to run a muffler when the one's that I have checked has been well below the 95 db. The lowest that I have seen was around 89db on the 3.5 outboards and the 3.5 hydro with out a muffler.

On the ballot it has a spouse vote ?I have two kids that race with me do there votes count also?

Roxy Sr. votes only count in IMPBA

Hi Don,

Russ's rule says "Measurements must be made from the shoreline area, between buoy #6 and the starting line" and, "the boat should be located approximately in front of the measurement device in one of the racing lanes on the front straightaway."

The boat will be in front of the meter! We are moving the meter to the right hand side of the course.

If your boat is below the 95db using the peak reading like Don uses, then you will be below when your boat is in front of the meter. If someone wants to use a peak reading for a National rule, and they have a good way of doing it then they can submit a proposal, thats how IMPBA works. When there's 7 boats on the pond racing and you get a 96db peak, how do I know which boat produced the peak? Is it the boat that just passed the meter or the boat entering turn 1? If you say, turn 1, then submit a proposal that has rule stating to point the meter at turn 1! I know they get a bit louder with this method, but this is not the current rule.

Fellas, heres how I did it at the regatta. The sound meter has a 1 second sampling period. This means it turns on the internal circuits and records the sound for a 1 second time period. Then the highest reading will be displayed for 1 second, while the internal circuits take the next reading.

The rule says to take the reading when the boat is in front of the meter. I have taken hundreds of readings and noticed that the meter might change the display before the boat is in front, while the boat is in front, or after the boat is well past, entering turn 1. I needed a constant method to judge all the boats when they were in front. The noisy boats will indeed have a higher reading when they enter turn 1, but this is not in front of the meter. This is an "errant reading" since like I said, they are not in front of the meter!

I was set up on the left of the driving stand and could not see the oncoming boats until they cleared the stand and a canopy. I also knew of the sampling rate. As soon as a boat appeared I quickly looked at the meter, if the meter display was not changing, I mentally noted the value. If it did change after the boat was about 25 feet past me, I recorded the value, since it meant that the boat was caught when it would pass the meter and about midway within a 1 second window. If the display was changing, then I knew the sampling period was over and the boat would be into turn 1 when the 1 second timeframe sample would end, and be displayed. The boat was not in front of the meter. In other words the sample was late and the boat was well past the meter. There is also a bargraph on the meter that I watched immediately if the display was not changing, this bargraph was faster than the display. The bargraph would show a quick upward swing. You can't wait to see the boat in front of you and then look down to take a reading, you will always be late, unless the display changes immediately. I had to spot the boat and then see when the display changed. Lots of readings were useless since I also needed to watch where the boat was traveling, many times the boat was wide on the course.

Moving the meter to the right hand side will eliminate blocking the view of the operator. He will easily watch for the display to change when the boat is at his right, look down at the meter, see the reading and wait till the sample is over, look up and see the boat heading toward the starting line. (I also saw that many boats were reasonably on the course). It will be much simpler and will have the reading taken when the boat is approximately where the rule states.

I'm not a sound expert, but have reported what I have seen. If someone knows of a better way to catch the boat in front of the meter, within a 1 second sample rate, (other than to use the timing traps), please let me know.

I don't race boats, but I do realize we need to quiet them down. The 92db is great, 90db is great, whatever the membership votes for is great, they are the IMPBA, I'm only 1 vote.

I will repeat what I found at the 2005 Regatta. If the level was lowered to 92db for that event, then only 9 boats out of the entire field at that race would be ILLEGAL, thats ILLEGAL. The rest of the 300 or whatever boats would be OK, no problems. I think that kind of noise reduction in only a year is fantastic, and everyone is to be congratulated for their efforts!

Since you think I am attempting to influence the vote I'll be sure to tone it down next time Don, thanks for bringing it to my attention.

John Equi

John,

Thank you for your reply & now it is far clearer that you propose the meter gets moved down to between bouy #6 & the starting line. This was not the case in the printed column of the Roostertail so on this far more detailed explaination I agree with you, as long as the meter is just to the right of the start/pit area so you still get a reading of a significant portion of the front straight. You still want to take readings with the pipe outlet facing the the meter (as in when the boats go by) as that will give a true & not reflected reading of sound pressure. Also it is not hard to single out an offending boat in a lap or two even when you have 5 or 6 out there as they all will not pass you & the meter at the same time.

As for the potential of influence on what you said in both Sept. & Dec. Roostertails regarding the noise proposal can you see how it may come across to someone besides yourself? I just didn't think that was fair to Russ who saw a potential for improvement, submitted a proper proposal & then gets not one but two shots (opinions) against him without a fair opportunity for rebuttal in the same form of media exposure you have in the Roostertail. Like I said before there is absolutely no disrespect intended whatsoever but you did interject some personal feeling & opinion on an issue coming up for vote in an area that is supposed to be for technical support & exchange, hence the title "Technically Speaking". You have provided great advice & technical support for many racers time & time again & for that I'm sure I can say we all are thankful. B)

I think your both WRONG. If you realy want to know how loud these boats are then the DB meter should be set at the entrance boey and pointed at boey one. Thats where they are the loudest. Better yet set the DB to 92 and have the reading taken in the pits when the boats start up. There's nothing worse than a boat with a nitro pipe and a canister that don't muffle anything start up next to you at 110DB. And don't say it can not be done, my sons sport 40 reads 88 on its stand with the meter 5 foot away and 78 on the water.

Buddy Benedict

Buddy Benedict said:

I think your both WRONG. If you realy want to know how loud these boats are then the DB meter should be set at the entrance boey and pointed at boey one. Thats where they are the loudest. Better yet set the DB to 92 and have the reading taken in the pits when the boats start up. There's nothing worse than a boat with a nitro pipe and a canister that don't muffle anything start up next to you at 110DB. And don't say it can not be done, my sons sport 40 reads 88 on its stand with the meter 5 foot away and 78 on the water.

Buddy Benedict

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And that would be a COOPER Pipe?.........Mikey

Buddy Benedict said:

I think your both WRONG. If you realy want to know how loud these boats are then the DB meter should be set at the entrance boey and pointed at boey one. Thats where they are the loudest. Better yet set the DB to 92 and have the reading taken in the pits when the boats start up. There's nothing worse than a boat with a nitro pipe and a canister that don't muffle anything start up next to you at 110DB. And don't say it can not be done, my sons sport 40 reads 88 on its stand with the meter 5 foot away and 78 on the water.

Buddy Benedict

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Buddy, what about your sons twin .90 rigger??

1fastracer said:

Buddy Benedict said:

I think your both WRONG. If you realy want to know how loud these boats are then the DB meter should be set at the entrance boey and pointed at boey one. Thats where they are the loudest. Better yet set the DB to 92 and have the reading taken in the pits when the boats start up. There's nothing worse than a boat with a nitro pipe and a canister that don't muffle anything start up next to you at 110DB. And don't say it can not be done, my sons sport 40 reads 88 on its stand with the meter 5 foot away and 78 on the water.

Buddy Benedict

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Buddy, what about your sons twin .90 rigger??

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Buddy got out of the twin class at the internats,his hair was thinning too fast.....Mike

I sold both of my TWINS at the nats this year. As for the pipe, Mikey is right it is a Cooper Pipe.

Buddy

Boy, I did a fly-by on that one!!!