Decibels - drill/de-baffle/de-mickey

[alexg57]

Hey guys,

I've had my '08 M50 for a little over a month and about 1000 miles now, and I love the bike and this site. I've learned a lot here, but one thing I haven't seen at all are accurate decibel readings for the different modifications of the stock pipes. I drilled my pipes after my 600 mile service - 8 x 5/16" - and I think they are significantly louder at all RPMs. I'm getting ready to de-baffle, but I would like to have an idea of what I'm getting into. When I first drilled the pipes I said, "Now that's the sound I was looking for!" Of course, now I'm not so sure. They do still sound a little hollow and a bit throaty (I've seen this described as "slap slap" and the puff sound). My wife even said, "It sounds like a Harley now!" Ugh.

I think I'll grab a decibel meter and measure the sound of my current set up while sitting on the bike (meter on top of my head to duplicate what my ears hear) and standing 15' in front of it and behind it. I'm hoping that you guys can help me fill in the rest - the same measurements with stock pipes, with de-baffled pipes, with de-baffle and de-mickey, and all "de-" modifications with and without DJ's fibrosleeves.

I think this could help a lot of us newbies with questions about whether or not to perform any [further] mods. I'm not out to sound like a Harley... I just want a bit more grunt in the sound

~ alexg

[alexg57]

Oh, one other thing. Since I'm trying to keep the decibels down, I doubt I will go any further than removing the baffle when it comes to tearing out plates. With just the baffle removed, will the fibrosleeve even change the sound significantly with regards to volume or tone? I feel like everyone who has done it has also at least de-mickeyed.

Again, having the decibel readings for fibrosleeve with and without the mickey (and even third plate) would be awesome knowledge.

Thanks!

~ alex

[Rockyrikoko]

Originally Posted by alexg57

Again, having the decibel readings for fibrosleeve with and without the mickey (and even third plate) would be awesome knowledge.

I think you may be a pioneer in this department. I have my 3rd plate removed, no fibrosleve, and don’t mind taking readings. What I don’t have is a way to take the readings.

What standard are you going to use for your readings. It would be best if everyone that participated did everything the same. In FL the police test if you’re legally too loud from 50'.

[nicocorea]

Originally Posted by alexg57

I feel like everyone who has done it has also at least de-mickeyed.

Nope, I've only removed the baffles and inserted fibrosleeves. The other 2 plates are still in. Here's a thread with some discussion on the topic...

http://www.motorcycle-journal.com/fo...se+fibrosleeve

[diamond_jim]

Originally Posted by Rockyrikoko

What standard are you going to use for your readings. It would be best if everyone that participated did everything the same. In FL the police test if you’re legally too loud from 50'.

http://www.4strokes.com/tech/measure_exh_sound.pdf

[alexg57]

Ah, thanks nicocorea, I do remember seeing that thread awhile ago. I'll end up with the same setup... at least initially

I just picked up a meatier drill and the hole saws I'll need, but I still need to get the fibrosleeve materials. Also, I asked around at Home Depot for a decibel meter and I was told they don't carry them. Any ideas where I might find one? I was thinking maybe a stereo or car audio store.

As for the article, DJ, I think their procedure would work as a standard to follow, but it's not realistic in how people (rider and pedestrians / other drivers) would hear the bike. It's talking about having the microphone at about the same height as the exhaust, about 20" behind, and at 45-degrees to the right. Nobody's head is at that level unless you just ran them over! I'm more interested in how the bike sounds to someone who may actually hear it. Thanks, though. Do you know of any other, more realistic standards?

~ alex

[tallannie]

Radio Shack sells one... 50$

Originally Posted by alexg57

Ah, thanks nicocorea, I do remember seeing that thread awhile ago. I'll end up with the same setup... at least initially

I just picked up a meatier drill and the hole saws I'll need, but I still need to get the fibrosleeve materials. Also, I asked around at Home Depot for a decibel meter and I was told they don't carry them. Any ideas where I might find one? I was thinking maybe a stereo or car audio store.

As for the article, DJ, I think their procedure would work as a standard to follow, but it's not realistic in how people (rider and pedestrians / other drivers) would hear the bike. It's talking about having the microphone at about the same height as the exhaust, about 20" behind, and at 45-degrees to the right. Nobody's head is at that level unless you just ran them over! I'm more interested in how the bike sounds to someone who may actually hear it. Thanks, though. Do you know of any other, more realistic standards?

~ alex

[Majestik]

Originally Posted by tallannie

Radio Shack sells one... 50$

I saw them on Ebay for $25-$40 depending on model and desired range/functions

[diamond_jim]

Originally Posted by alexg57

As for the article, DJ, I think their procedure would work as a standard to follow, but it's not realistic in how people (rider and pedestrians / other drivers) would hear the bike. It's talking about having the microphone at about the same height as the exhaust, about 20" behind, and at 45-degrees to the right. Nobody's head is at that level unless you just ran them over! I'm more interested in how the bike sounds to someone who may actually hear it. Thanks, though. Do you know of any other, more realistic standards?

~ alex

I did my recordings from 18" and 15' directly behind and in line with the exhaust.

[SNAFU]

to M-J Alex!

You've got a good idea there, it would be neat to hear the sounds of the M50 pipes in different stages.

I just recently heard fibrosleeve sound clip and it sounded awesome.

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I AGREE

At 15 feet

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I AGREE

[alexg57]

Originally Posted by SNAFU

to M-J Alex!

You've got a good idea there, it would be neat to hear the sounds of the M50 pipes in different stages.

I just recently heard fibrosleeve sound clip and it sounded awesome.

I've also saw those (thanks, Jim and those who helped you get them posted ). The only thing that concerns me is that I think the sound is deceiving. I tried to record the sound of my bike before and after drilling the pipes, but my camera's microphone would always overload and sound distorted when it finally made it onto my computer. I bet Jim would probably say that his recordings don't sound exactly like it sounds like in real life. That's why I'm really interested in getting a non-subjective measurement of one part of the sound of a bike - the volume.

And speaking of which, thanks for the tips on pricing for decibel meters, guys. I think I'll just borrow my father-in-law's for this one job. No sense in spending 50 bucks on something I'll only use once!

[Drtoronto]

ok folks you asked you get

with my spl meter
not running just ambiant noise

here it is at idle

and now at idle about 2 inchs from the pipe


and max level almost full throttle

and heres how far back i put the meter


My bike is just debalfed nothing else thats pretty loud!!
here the rating sheet for the meter

[Majestik]

Originally Posted by Drtoronto

with my spl meter
not running just ambiant noise

you mean on this measurement the bike is OFF? or Idle?

I guess seeing the bike keys on the ground next to the boom, the bike is OFF

I would love to see the measurement for the Idle on debaffled pipes.

[Drtoronto]

its just off ill do a idle give me a sec

edit ok look in my post now

[alexg57]

Damn, 67 decibels ambient? Where are you, next to a highway?

Anyway, thanks for the numbers. I couldn't wait around to measure some sounds on mine when it was stock, so I already have a full de-baffle/de-mickey/fibrosleeve. I'm heading down to my father's house this weekend, and I'll borrow his decibel meter for the testing. If he lets me take it home, I'll also be able to test a coworker's stock set up. Look for the numbers soon.

Dig!

~ alexg

[Mario]

I am running straight pipes yea! for about a month I will run down to the Shack and pick one up...or better yet Fry's and hopefully get back with you.