So the non-trolling advice is to de-tune the car?? That's a joke right? What next? Remove the turbo? (Actually that would make it louder). Buy a base Lancer and be done with it.

 

this might be my only gripe with the evo x. For a $38k car (including the SSS package of course)...it just doesn't feel like the quality inside is worth $38k dollars. i had the evo 8 and that car was made much better in terms of quality (i.e. doors shutting with more of a thud; the door handles feel more solid; the car itself felt more dense and substantial; there was less plastic and more leather in the dash area). i mean, they are little things but those should factor into spending that much money on a car. That's why i bought used. I can't justify $38k. but for $29k for a 2011, I'm in! lol oh, and i wish the seat sat higher. i'm only 5'8" but from the outside looking in, people say i look like a little kid

other than that...i f-ing love it!

 

Possibly useful information:

Besides the frequency of the exhaust pulses (which, of course, is determined by rpm, but is also altered by the turbo), drone depends mostly on the thickness of the walls of the exhaust tubing. But the relationship between tubing thickness and drone is not simple. It's not something as easy as "thicker walls drone less" (as anyone who has ever been in an Evo with an Agency Power exhaust knows). What wall thickness does is alter the resonate frequency of the tubing, so it mostly determines at what rpm the droning will be worst.

The other issue to keep in mind is how changes in exhaust temp (which, obviously, falls as you move from front to rear) can influence drone by, effectively, altering the amount of exhaust that is flowing. This is where the placement of resonators comes in. It appears that, on Evos, the key location is about 18" before the rear axle. In general, exhausts with a resonator in this location are much quieter, but this will depend on the tubing, so that's not an absolute rule.

 

My setup, Agency Power Headers, down pipe, cat delete, and a Buschur Racing Crossflow at idle is actually quieter than stock (On a dB meter) but I don't have the pictures to go along with the claim. However, once you break 3.5k is opens up and get's loud.

So, if you are driving sane in town, it's really nice. Break that 3.5k and you can definitely hear yourself. best of both worlds imo.

 

The trolls are weird. They continuously add nothing to threads as if they're compensating for something. Seems like there's a striking similarity between troll mentality and college fraternity hazing mentality. "Do your pushups naked until I can see the sweat gleam off your *ss, fish!" Probably would make a great psych paper.

Anyway, I feel your pain. Much of this info comes from www.sounddeadenershowdown.com. The interwebs seem to indicate that there only three (3) ways to accomplish your goals:

1) Stop body panels from resonating.
2) Absorb the sound.
3) Block the sound.

Due to the thickness of insulation required to accomplish item (2) (think about feet rather than inches), it is not practical for auto applications.

You're stuck with (1) & (3), which appear to be relatively easy to accomplish - panels only need about 25% coverage with a CLD to stop their resonance. No big weight penalty but resonance should be pretty much thwarted.

Item (3) is where you pay weight penalties. You need something with a lot of mass to block sound.

I've got to find all the links that back up the info; they'll come in subsequent posts. I'll also post some links on the products that I've researched.

 

Maybe this would help:
http://apexi-usa.com/shop/index.php/...-silencer.html

 

It would appear that empirically, a "mass law" governs sound transmission loss; the greater the mass of the barrier, the greater the energy required to set it in motion and therefore transmit the sound.

http://www.kemt.fei.tuke.sk/Predmety...nsmission.html

In reality, this is an oversimplification because it assumes the angle of incidence of the sound is 90 degrees to the barrier. It rarely ever is so the BEST we can hope for is a 6 dB reduction in noise for every doubling of mass.

http://www.armacell.com/www/armacell...sionLossUK.pdf

Interesting as that may be, what you really care about: minimizing weight and noise is going to require some personal compromises. Predominantly, what product do you use to accomplish the goal and how? The interwebs seem filled with success stories of a multi-layer approach:

Bottom Layer: dampening. I'd probably use CLD on 25% of the area of panels rather than some sort of other product.

Middle Layer: decoupling layer - something to "float" the barrier layer so the barrier is more difficult to excite into sound transmission. This appears to be critical. I'd probably use a closed cell foam.

Top Layer: sound barrier layer - this is the sound reflector that's the really heavy part, subject to the Mass Law. I'm undecided on this; Mass Loaded Vinyl barrier is popular but in comparing some specs, there could be some exotic stuff out there.

I'll post a few links and specs to the sound barrier info that I've found in a subsequent post.

 

Note: Dynamat, Dynamat Extreme, and RAAMMat are not barriers; they are dampeners.

No shipping costs included; those are a b*tch for stuff that's this heavy.

Sound Deadener Showdown MLV:
Cost PSF (135 SF roll): $2.11
Weight: 1 lb / SF
Thickness: 0.107 in (2.7mm)
Frequency (Hz) & Associated TL (transmission loss in dB):
0125 - 15
0250 - 19
0500 - 21
1000 - 28
2000 - 33
4000 - 37

Second Skin Audio Luxury Liner:
Cost PSF (90 SFl): $2.67
Weight: 1 lb / SF
Thickness: ~0.125 in (~3.175 mm)
Frequency (Hz) & Associated TL (transmission loss in dB):
0125 - Not available
0250 - Not available
0500 - Not available
1000 - Not available
2000 - Not available
4000 - Not available

Second Skin Audio Luxury Liner PRO:
Cost PSF (90 SFl): $4.00
Weight: 1.25 lb / SF
Thickness: 0.250 in - 0.375 in (6.35 mm - 9.525mm)
Frequency (Hz) & Associated TL (transmission loss in dB):
0125 - Not available
0250 - Not available
0500 - Not available
1000 - Not available
2000 - Not available
4000 - Not available

Cascade Audio VB-3 (Lead Based):
Cost PSF (135 SF roll): Not available on website
Weight: 1 lb / SF
Thickness: 0.25 in (6.35 mm)
Frequency (Hz) & Associated TL (transmission loss in dB):
0125 - 18
0250 - 20
0500 - 25
1000 - 32
2000 - 34
4000 - 36

Cascade Audio VB-4:
Cost PSF (135 SF roll): Not available on website
Weight: 1 lb / SF
Thickness: 0.25 in (6.35 mm)
Frequency (Hz) & Associated TL (transmission loss in dB):
0125 - 16
0250 - 18
0500 - 22
1000 - 28
2000 - 33
4000 - 36

Dynapad:
Cost PSF (135 SF roll): Not available on website
Weight: 1.09 lb / SF
Thickness: 0.452 in (11.48 mm)
Frequency (Hz) & Associated TL (transmission loss in dB):
0125 - Not available
0250 - Not available
0500 - Not available
1000 - Not available
2000 - Not available
4000 - Not available

EAR Specialty Composites (a 3M Company) WB-10:
Cost PSF (135 SF roll): Not available on website
Weight: 1.0 lb / SF
Thickness: 0.077 in (1.9558 mm)
Frequency (Hz) & Associated TL (transmission loss in dB):
0125 - 15
0250 - 16
0500 - 21
1000 - 26
2000 - 33
4000 - 38

EAR Specialty Composites (a 3M Company) R803-25-10-100SM:
Cost PSF (135 SF roll): Not available on website
Weight: 1.1 lb / SF
Thickness: 1.35 in (34.29 mm)
Frequency (Hz) & Associated TL (transmission loss in dB):
0125 - 15
0250 - 17
0500 - 19
1000 - 26
2000 - 37
4000 - 50

 

OP get a stock exhaust from a 2008 , that should help you quieter it and someone more performance oriented will trade you... I have my stock exhaust sitting in my garage and would trade you or sell it for a few bucks if you were closer. Good luck

 

This will be the case with any exhaust that utilizes a side-inlet muffler. If you place it correctly, the Vibrant Performance 3" side-inlet muffler should be pretty quiet (assuming you want to make your own exhaust). Placement and size of resonators is key in the midpipe section. At the end of the day, it will be about trial and error. Exhaust noise reduction is unbelievably complicated (if you are really serious about eliminating all frequencies of sound). Bare in mind, what works to reduce sound at one RPM or in one RPM range might not work in another. I had an acoustic engineer try and explain all of this to me, one day, and it went right over my head (well, at least some of it did).

 

 

I just put on a MAP Performance Varex catback with an Ultimate racing mini-muffler test pipe and it sounds at least as quiet as stock with the valve closed but still has some growl when open. I can't imagine how quiet it would be with the stock cat in place. Def a good purchase as long as the valve keeps working.

 

Yeah, I was going to suggest that combo, Varex mufflers with the ETS or UR mid-pipe mini muffler. That should quiet it down a lot.

Easiest way to get a quiet exhaust is to buy a Ralliart instead of an Evo X...

 

he's not entirely wrong. from stock 2012 exhaust to cobb (i have oval, not quad) i have less drone at all rpms especially sub 2000 rpm. the factory exhaust when revving down would sound like a subwoofer test frequency. i thought it was a pretty cool noise myself.

of course the cobb exhaust exhaust is louder above 2500 rpm but it's quieter (or feels like it since it doesn't buzz) from 1200-2500 rpm. it would say it's somewhat equal at idle in car, windows up. no doubt it is louder outside of the car at all rpms.

oh, i went from HFC to gutted high flow cat and it quieted down in cabin noise a bit.

 

Huge thanks for the numerous helpful suggestions, folks!

After some additional thinking, I realized that it is the drone (low-frequency sounds and vibration) that is the largest source of grief for me, not the overall SPL inside the cabin. In fact, that Cayman I replaced with Evo seemed to have had, overall, a louder engine. However, it was drone-free, and at the same time not as tinny as EVO's.

To draw a parallel with an orchestra, I'd describe the engine sounds as follows:
Evo: tenor + mezzo-soprano singing alternatively, accompanied by a farm tractor
Cayman: a well orchestrated trio of a baritone, tenor, and a mezzo
Although I miss the baritone, I can live with the tenor + mezzo, but the tractor HAS to go.

Therefore, I think the goal should be reformulated as follows:
Completely get rid of the drone at all RPMs, preferably, but not necessarily, keeping the overall exhaust SPL comparable to stock.