If you like to enjoy your music and not listen to road noise then sound deadening is a must........there are many ways to accomplish this task and I would like to share what I have learned over the past few years from a former professional car audio installer. I do not know it all, and don't pretend too.......please add any comments I left out, or if I made a mistake.

I lowered the road noise in my coupe from 75 db to 68 db...... a significant reduction in ambient noise....it made my listening experience that much better!

I will start off with Dynamat installation.........

I have seen many car pics posted here where the owner has dynamatted the entire trunk, or under the back seat or the door panels........this will reduce noise, but blanketing an entire section of the car has a relative high cost, adds weight and IMO not necessary. Dynamat is used on "large" metal panels to reduce the vibrations caused by road noise (outside in) and your music (creating unwanted noise/vibration).

Places I added dynamat (actually used Brown Bread, about 1/2 the cost), inside both doors on the outer skin, inside both rear cavities on the outer skin(actually placed 2 pieces on the rear outer skin, one big piece can be seen in the attached picture and the other smaller piece is in the trunk on the same panel), and the trunk lid. There are a few smaller pieces I added in the trunk on both sides and any flat area on the rear speaker deck.

You can hear the difference by knocking on the outside skin of the G before dynamat, you will hear the knock vibrate the metal......after dynamat all you should hear is a "thud"

 

Next item to use is spray foam........the non-expanding type. I filled the entire trunk lid (pic was shot before i shaved the excess foam off) and the cavity between the trunk and back seat (zoom in on the 3rd pic and you can see the holes are filled with white foam). Go slow, spray....wait to expand, spray some more....wait...etc.......to make sure you allow the foam to expand not deform the trunk lid! If you use the wrong kind of foam, your asking for trouble!

Afterwards, my trunk lid was DEAD......when you knocked on the lid it did not vibrate at all........

 

Next I used attic insulation to fill the LARGE cavity between the outer and inner skin.....this area acts like a box and sound bounces around in there....a very cheap $15 roll of insulation (there is a brand that has a cover, like a plastic bag) and stuff it in there.....i used almost the whole roll and stuffed it everywhere there was a space.....think of insulation in your house between rooms....most houses dont have any and you can hear what goes on next door, but with insulation.....dead!

 

Finally I used carpet underlayment to add more insulation for the panels.....all the panels, just glued it to the inside of the panels and snapped them back on!

 

Hey shooter, these are some great tips you are sharing with us. I really appreciate it since I will soon be doing my audio install. By the way, where did you get your non-expanding spray foam from?

Thanks,
Mike

 

Home Depot........there is the blue can type and another color can (can't remember the color, but think its red)......read the label and make sure it is the non-expanding type.....it also has the benefit of being water soluable so it cleans up with water....the other kind you need solvent

it takes a while to dry when you fill up the large cavity.....days, but no big deal, just dont get it wet.

if you want let me know and i'll come on by and help if i can

 

wow...that looks pretty awesome and must sound great as well.

it is always nice to see how different people to things differently.

vinh

 

Looks like a very nice job. Looks like your hard work paid off! 7 decibel difference is fantastic, almost like day and night. How long did it take you from start to finish?

Your pics look nice, maybe you can post more about your audio system?

I am the new guy on the block for car audio on the G35.

 

Looks good! Just one work of caution...I've done this before in a much older car. Just make sure none of this stuff can get wet. That spray foam is great for soaking up water, and man does it stink after it's baked in the sun for awhile!

 

i spent my thanksgiving holiday installing the sound system.....took 7 days for the entire install......i would say about 4 of those on the sound deadening, but it really is worth it to me.......

thanks for the heads up jeepman.....hmmmmm didnt know that part, im trying to think how could the foam get wet?

i have posted my trunk pics........the cabin looks stock as i used the factory HU

thanks to all for the props

 

here is a few install pics................

i hope this helps or gives you some ideas......i have learned so much from this site (and continue to do so) i would like to give something back

 

very nice job and very creative ... i'll be doing same thing ...
i would also put some sort of foam around your front speakers so all the sound goes outside

 

Shooter can you label what's all that wiring and components in those pictures. Use photoshop or paint to describe...

 

I am working on enclosing the rear deck speakers and the door speakers........i am lucky enough to have access to a stereo lithography machine (a 3d printer, prints plastic parts). I have started with the rear deck speakers........i am on my 2nd prototype and have installed 1 enclosure so far..... the second one is printing as i type and should be done tomorrow (takes about 60 hours to print 1 enclosure), so i will install the 2nd this weekend........the mid bass punch has improved slightly with 1 speaker enclosed, and im looking for a better improvement this weekend. I am still tweaking the enclosure size and shape to get it right. will post some pics this weekend........after that i will work on the door speaker enclosures......

birdhouse......i can post a labled pic or 2, but it wont be until this weekend.....i dont have a program handy and will need to do some searching to find a free one.......and then create the pic!

 

60 hours for what???? so you are getting god midbass off the rear spkeaker 6x9 ???
why bother???? can you post some PICS

thanks