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Discussion Starter #1
Hey guys,

Just curious, does anyone actually have any decibel (dB) figures on our bikes with different exhausts? They are passing laws here with 96 dB restrictions etc, I'd like to see by how much my bike will fail.

Tried searching for previous threads but came up short...
 

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V's and Z's
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Here's how Myrtle Beach does it. They hold the meter 2 feet back of the muffler tips and up at 45*. At idle, if it's over 92dB, you fail. I have a Radio Shack dB meter and my VMods were 90dB at idle.
 

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There are videos here posted somewhere taking the DB measurements in a Dyno, I think it is with the Indy pipe... I think the DB measurement is an standard for comparison purposes, but some pipes or bikes are actually louder but with a lower tone (like air cooled ones); louder Vrods tend to be a little less loud volume-wise speaking, but the tone is higher and REALLY capable of pissing the ear of those on top and around the bike... It's all a matter of frequencies and which ones of them the ear captures and are processed in a different way by the brain. Or something like that, LOL!
 

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durata membro
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With all the states enforcing their exhaust emission standards and states that didn't have laws adopting new ones,I see that we are going to wind up w a federally regulated standard for sound emissions,similar to the exhaust emission standards we have for the chemicals that are emitted out the exhaust.
 

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I believe federal laws (Ct as well) are 80 DB 50' straight behind the bike. No rule on RPM's to test at. I got pulled over and tested with V&H widows (which most say are not loud at all) and I failed at 91 DB with about a 4 to 5K throttle peak. I got a verbal warning. Next time I won't twist the throttle as hard.
 

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Here's how Myrtle Beach does it. They hold the meter 2 feet back of the muffler tips and up at 45*. At idle, if it's over 92dB, you fail. I have a Radio Shack dB meter and my VMods were 90dB at idle.
That bylaw went into effect here in the spring. Ours is 92 db at idle and 96 at 2000 rpm, for twin cyl bikes. I had mine tested before they were handing out tickets, with Bub 7 2-1, it measured 100 at idle and 105 at 2000. I had a Thunderheader on last year and it was quite a bit louder but I never tested it for actual numbers.

There was another V-Rod there when I was with a CFR and quiet baffles. If I remember right his was 96 and 99.

The cops said at the time, almost anything other than the factory exhaust will fail. There were even some older stock exhausts that were failing.
 

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Hey guys,

Just curious, does anyone actually have any decibel (dB) figures on our bikes with different exhausts? They are passing laws here with 96 dB restrictions etc, I'd like to see by how much my bike will fail.

Tried searching for previous threads but came up short...
A few months back when they pushed one of these loud exhaust laws though up here in Canada, (Edmonton to be exact) I went out and got one of those $50 Radio Shack Sound Level Meters. I didn't calibrate it against a known source, but figured it would be close enough. At idle at 2ft away and 45 degrees from directly behind I got a whopping 110+ dB with my Street Fighter Bullets. I knew they were loud but holy crap.

To make a long story short I had a friend make some sweet looking end caps and baffles for them and not only are the quieter (~100 dB) but they actually sound better too. (Deeper)

They are still pretty loud but I figured that if the bike isn't obnoxiously loud I probably won't raise any eyebrows or give the police any reason to pull me over.

Oh yeah, my bike is a 07DX.
 

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These laws certainly make a case for the systems like the.jekill and hyde ones. Quiet and loud. Hopefully you just get a not so bright cop.

http://www.jekillandhyde.eu/
 

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Anyone have any experience with the accuracy of any of the decibel meter iPhone apps? There's about two dozen of them.
 

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Discussion Starter #14
which rinehart? the 2-2?
The 2into1. I downloaded that video from the other thread. The meter is pretty far away from the bike, but I assume it is getting louder readings because it is indoors vs outdoors?
 

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Isld Shite Disturber
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The 2into1. I downloaded that video from the other thread. The meter is pretty far away from the bike, but I assume it is getting louder readings because it is indoors vs outdoors?
well sure the guy is standing farther away but he's the same distance on all the vids..... I think those vids are great to actually see how each pipe sounds on accel and decel....and a rough idea on the DB rating as well...I know when I exhaust shopping I used these vids to help me decide and have not regretted my choice
 

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Anyone have any experience with the accuracy of any of the decibel meter iPhone apps? There's about two dozen of them.
I can't speak directly to the IPhone apps, but I tried out an Android app and its default was about 10 dB above the my Radio Shack Sound Level Meter over quite a large range (I tried it from 60 dB up to 100 dB). However the app allowed you to calibrate it, so I just made it match the SLM and then it read pretty much the same as the SLM. I suspect that, if you had a known sound source you could calibrate it to, the IPhone apps would probably do a pretty decent job. (At least for what we're using it for)
 

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As many iPhones as there are amongst members here and probably crossover apps made for both android and iPhone I bet we could pick an app, have several of us download it and get pretty consistence comparisons of all the different systems we're running. Maybe not precise db levels but pretty accurate comparisons from one system to the next so people would have a basis to judge how much louder one exhaust is than another.
 

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As many iPhones as there are amongst members here and probably crossover apps made for both android and iPhone I bet we could pick an app, have several of us download it and get pretty consistence comparisons of all the different systems we're running. Maybe not precise db levels but pretty accurate comparisons from one system to the next so people would have a basis to judge how much louder one exhaust is than another.
I currently have the SPL sound meter app. and have no way of telling if it is accurate or not. I used it yesterday to test my Supertrapp fat shots and came up with 98dB at idle in the underground. I used it at approximately 45 degrees and 2 feet away as I have read that is what the police in many areas use and wanted to duplicate. I feel that with the sound bouncing off walls and vehicles that it is probably as good as a bar's in house Breathalyzer test. Close enough to keep you out of trouble.
 

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As many iPhones as there are amongst members here and probably crossover apps made for both android and iPhone I bet we could pick an app, have several of us download it and get pretty consistence comparisons of all the different systems we're running. Maybe not precise db levels but pretty accurate comparisons from one system to the next so people would have a basis to judge how much louder one exhaust is than another.
I think your idea is cool, but hard to do in practice. The main issue is the wide variety of hardware out there. Even if we wanted to have nothing but a relative scale, we still need to be relative to some known volume and frequency source that would show up as the same dB for everyone. There are a ton of websites out there where you can download tones that you can playback through your speakers that we could all use to calibrate against, but this would require that we all have our speakers set to the same volume.

I guess a quick and dirty way to do it is to all select a sound file that we'll all play through our speakers at whatever volume gets the SLM App to read some decided upon dB (say 80 dB). (At a fixed distance) In that way we can at least compare the relative loudness of the exhausts reading against and agreed upon source. It wouldn't be perfect by any stretch, but it might do the job.

I'm sure there are some sound guys out there who could come up with better ways.
 

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brett
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this is a cool idea.i dont have a i phone but im sure i could borrow one of a mate and use it for this as im sure a lot of people could do ..even better if lots of people with the same exhust did this to get a really good average for that system .although id like to imatate the garage of the cops ,id think it easier and more accurate for all to do it on the side of a quiet road or in a park out in the open .

Lets thinks up some guide lines to sinc everyone for when they do a sound check,eg 2 ft behind in line with the pipes outlet
 
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