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Discussion Starter · #1 · (Edited)
Does anyone have a sound clip for an FMF Q4 on their WR250X? I know its supposed to be 93db, but how loud is that compared to the FMF Power core 4 that is 100db? Any help greatly appreciated :thumbup:
 

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No matter where you start, +3 dB is a small but noticeable increase.

+6 dB is "twice as loud". Well, twice the sound pressure, anyway.
Some people say +10 dB sounds "twice as loud".

=> 100 dB is about twice as loud as 93 dB.
 

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I have the Q4 and it's not annoyingly loud. My guess is that it's about the same as my stock YZ250F exhaust, and has a nice tone to it. I heard the Powercore on a DRZ and thought it was way too loud for street use.
 

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Just for reference, anyone know what the db is for the stock pipe?
 

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The sticker states around 88db at like 5,000 rpm.
I was told the flapper thing above the airbox, that people like to modify in this forum,
was to keep the compliance of sound/rpm with whomever (govt official) is concerned.

....or something like that.:headscrat

...Im sure someone here can elaborate on this:thumbup:
 

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Thanks guys...

So if I got this right, the Q4 is nearly 2x as loud as stock, and the Powercore is 2x as loud as the Q4?:eek:

http://www.sengpielaudio.com/TableOfSoundPressureLevels.htm
By those numbers, yeah, pretty much. Q4 is +5 dB (almost 2x stock), Powercore is +12 dB (4x stock). Assuming they measure them the same way...

But remember, the stock bike isn't all that loud to start with. So imagine 2 stock bikes next to each other to get the volume of a Q4, and 4 stock bikes moving in unison to match the volume of one Powercore. (Different tone though.)

"Loud" is relative... I wonder how my old Shovelhead with 2" straight pipes would have measured? Man, that bike would rattle windows a block away when I opened up and let 'er rip. :arsenal Heh. Good times. :bike: But a bit conspicuous... It'll be a Q4 for me this time around. :thumbup:

View attachment 44407
 
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