DIY Noise Reduction

B&W_Evader · 10-07-2011, 02:36 PM

Just got done doing the road test.
Speed was 65 mph
Data points w & w/o were done in 2 direction on the same stretch of hwy. Attempted to take readings in approximately the same spot to keep it controlled. 2 positions on meter, next to my right ear and approximately 4" off the center of the rear deck. Car was 6th gear, cruise control.

With---Without
74.9---76.8---Head
78.6---80.9---Head
76.8---77.9---Deck
79.0---83.0---Deck

I'll take it.

Guard Dad · 10-07-2011, 09:33 PM

Quote:

Originally Posted by B&W_Evader

Just got done doing the road test.
Speed was 65 mph
Data points w & w/o were done in 2 direction on the same stretch of hwy. Attempted to take readings in approximately the same spot to keep it controlled. 2 positions on meter, next to my right ear and approximately 4" off the center of the rear deck. Car was 6th gear, cruise control.

With---Without
74.9---76.8---Head
78.6---80.9---Head
76.8---77.9---Deck
79.0---83.0---Deck

I'll take it.

Those are substantial drops. The db scale is logarithmic, each 3 db drop is roughly a 50% reduction in sound levels. My reading is 67-68 dba (hit a bump and it goes higher) after all my work, however this can't be directly compared to yours because my meter is an iphone app not a calibrated meter. But for the sake of reference I get about a 66-67 db reading in the house (crickets outside an open window really show up on the dba scale) with the TV off yet there is no way that the car seems as quiet as the house.

B&W_Evader · 10-10-2011, 09:33 AM

Yeah, and if someone coughs 3 feet away it skyrockets. Had to reset it every time I heard a rock bounce off the bottom of the car since I figured it captured it as the peak reading. Still would be nice to get it down a little more. Was looking at getting under the 3 furthest back panels in the back for the next step but mainly focusing on the strut towers.

Also, put the sound meter by the door panels and wasn't as high as the back still. Driver's side was definitely louder. Anyone know why that might be or do you think the road was just rougher on that side?

'10Anamoly · 10-10-2011, 11:17 AM

So you bought the 1" thick, 0.75 NRC Skinned foam? How many feet long was the piece that had enough to do the trunk? I see that it is 54" wide by how ever many feet you buy. Was this the type without adhesive?

WhiskeyHotel · 10-10-2011, 03:51 PM

Quote:

Originally Posted by '10Anamoly

So you bought the 1" thick, 0.75 NRC Skinned foam? How many feet long was the piece that had enough to do the trunk? I see that it is 54" wide by how ever many feet you buy. Was this the type without adhesive?

Yea, I am wondering the same thing. If it had the adhesive, maybe I could stick it on the back or on top of the thin bottom mat.

B&W_Evader · 10-10-2011, 06:01 PM

No adhesive on mine.

I bought 6ft of 5692T13 but you can see how much is left over. Should be plenty to get a couple more dBs out of it. Adhesive might be nice but I have no idea how aggressive it is and whether it would stay bonded to anything.

koffeegy · 10-10-2011, 06:53 PM

Quote:

Originally Posted by WhiskeyHotel

Yea, I am wondering the same thing. If it had the adhesive, maybe I could stick it on the back or on top of the thin bottom mat.

The adhesive is there so you can get a good fit to the metal. The material actually helps reduce the vibration in the metal from the travel, which make the road noise. Just placing the material in the trunk would possibly help, but you would see a much bigger difference if it was glued down to the metal. I have been into car stereo's since high school, so I have seen a thing or two. Hope this helped.

REP please and thank you,

Guard Dad · 10-10-2011, 12:04 PM

My experience suggests that doing the the ENTIRE hatch area (I did the wheel wells but not the back side of the rear fenders) and the doors (the area behind the trim panels-also a great time to upgrade the door speakers) is the best first step. A 38 square foot box of Dynamat Extreme was just enough to do the job.

When that's done you'll be able to decide if you want more or if you are good-to-go.

10-07-2011, 02:36 PM	#1 (permalink)
B&W_Evader Track Member Join Date: Aug 2011 Location: CA Posts: 972 Drives: slower than before Rep Power: 387	Just got done doing the road test. Speed was 65 mph Data points w & w/o were done in 2 direction on the same stretch of hwy. Attempted to take readings in approximately the same spot to keep it controlled. 2 positions on meter, next to my right ear and approximately 4" off the center of the rear deck. Car was 6th gear, cruise control. With---Without 74.9---76.8---Head 78.6---80.9---Head 76.8---77.9---Deck 79.0---83.0---Deck I'll take it. Last edited by B&W_Evader; 10-07-2011 at 02:43 PM.

10-10-2011, 11:17 AM	#4 (permalink)
'10Anamoly Track Member Join Date: May 2010 Location: GA Posts: 882 Drives: 2010 370Z BS M6 Rep Power: 16	So you bought the 1" thick, 0.75 NRC Skinned foam? How many feet long was the piece that had enough to do the trunk? I see that it is 54" wide by how ever many feet you buy. Was this the type without adhesive? __________________ 2013 Ford Mustang GT 374rwhp, 360rwtq SAE / GT500 Axle-Backs / Brembo Pack / Track Pack / Recaros / 6spd Last edited by '10Anamoly; 10-10-2011 at 11:20 AM.

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10-10-2011, 09:33 AM	#3 (permalink)
B&W_Evader Track Member Join Date: Aug 2011 Location: CA Posts: 972 Drives: slower than before Rep Power: 387	Yeah, and if someone coughs 3 feet away it skyrockets. Had to reset it every time I heard a rock bounce off the bottom of the car since I figured it captured it as the peak reading. Still would be nice to get it down a little more. Was looking at getting under the 3 furthest back panels in the back for the next step but mainly focusing on the strut towers. Also, put the sound meter by the door panels and wasn't as high as the back still. Driver's side was definitely louder. Anyone know why that might be or do you think the road was just rougher on that side?

10-10-2011, 06:01 PM	#6 (permalink)
B&W_Evader Track Member Join Date: Aug 2011 Location: CA Posts: 972 Drives: slower than before Rep Power: 387	No adhesive on mine. I bought 6ft of 5692T13 but you can see how much is left over. Should be plenty to get a couple more dBs out of it. Adhesive might be nice but I have no idea how aggressive it is and whether it would stay bonded to anything.

10-10-2011, 12:04 PM	#8 (permalink)
Guard Dad Enthusiast Member Join Date: Aug 2010 Location: South Orange County, CA Posts: 422 Drives: 2010 370Z Silver A7 Rep Power: 15	My experience suggests that doing the the ENTIRE hatch area (I did the wheel wells but not the back side of the rear fenders) and the doors (the area behind the trim panels-also a great time to upgrade the door speakers) is the best first step. A 38 square foot box of Dynamat Extreme was just enough to do the job. When that's done you'll be able to decide if you want more or if you are good-to-go.