Sound dampening..

[sil3nt_dr3ams]

When I finished my latest project I'll get to it http://www.nissanpatrol.com.au/forum...003#post440003

[04OFF]

Westy you figure out someway we an benchmark/test it haha

During my home cinema design/testing, i needed to test sound insulation, so i built a MDF box with open sides at opposite ends, (a square tube in otherwords), attach/suspend a db meter to one end, then cover the other end with the test product.


Place a hifi speaker at a set distance on the opposite end to the db meter (so now the sound has to travel through the test product to get to the db meter) play a set track/recording through the speaker ,play sounds with frequency/s around what you expect to encounter (you could record the car noise you wish to reduce).



This can allow you to "hot swap" different products fast and easy in a semi controlled enviroment (well compare apples with apples anyway), and while not studio accurate, its much better than swapping it on the car to find out/guess, plus you only need small samples to test each product.



Simulated compressing of a soft product ,can be done by sandwiching the product between chicken wire (or steel mesh etc), if you fix chicken wire across the open test end of your bare box for "all" testing, all you need to do is use another peice of chicken wire over the outside, to now compress the test product.


Use screws into the body of your MDF box as fixtures, so you can attach cable ties or wire around them, this will allow you to pull the outer piece of chicken wire toward the chicken wire on the box, and so compress the test product that is sandwiched between them, but still allow sound to pass.

[sil3nt_dr3ams]

Okay, so putting everything you said into play,

http://www.ebay.com.au/itm/Mini-USB-...item19d726a14a

I'm thinking two of these one inside the car one outside the car with a external sound source. As long as the two cheap db testers read the same and the external sound level is the same it should be a good place to start.

[BigRAWesty]

During my home cinema design/testing, i needed to test sound insulation, so i built a MDF box with open sides at opposite ends, (a square tube in otherwords), attach/suspend a db meter to one end, then cover the other end with the test product.


Place a hifi speaker at a set distance on the opposite end to the db meter (so now the sound has to travel through the test product to get to the db meter) play a set track/recording through the speaker ,play sounds with frequency/s around what you expect to encounter (you could record the car noise you wish to reduce).



This can allow you to "hot swap" different products fast and easy in a semi controlled enviroment (well compare apples with apples anyway), and while not studio accurate, its much better than swapping it on the car to find out/guess, plus you only need small samples to test each product.



Simulated compressing of a soft product ,can be done by sandwiching the product between chicken wire (or steel mesh etc), if you fix chicken wire across the open test end of your bare box for "all" testing, all you need to do is use another peice of chicken wire over the outside, to now compress the test product.


Use screws into the body of your MDF box as fixtures, so you can attach cable ties or wire around them, this will allow you to pull the outer piece of chicken wire toward the chicken wire on the box, and so compress the test product that is sandwiched between them, but still allow sound to pass.

Did you just have speaker playing music? Or did you play a propper dB?

[Parksy]

Have purchased 10 of those sheets from jaycar. Will combine that with the dynamat I've got coming and hopefully will have a nice ride. Will let you know how it goes.

[BigRAWesty]

So are you takeing the fat Mat out or just continuing the lay out?

[Parksy]

Will leave the fatmat in for now and just do the sections that I haven't done yet, which is the majority of the floor, except for the cargo area.
Edit: while the fatmat wasn't specificly designed for noise control, it has made a big difference to noise and vibrations, so until it falls off, I might just keep it in.

[BigRAWesty]

Fair enough. I was thinking about the fat Mat. It would probably be fine for the floor pan hay.. Not like it can fall further.. Lol
I might grab some dynamat for the firewall. Also thinking of that paint on stuff for the wheel arches.
Mate we'll have the quietest patrols ever..

[Parksy]

Haha that's the plan. I fitted a 2.5" exhaust with a straight through muffler and took the family for a trip down to Canberra. Wife wasn't impressed, so I swapped the muffler for something quieter and will continue with the soundproofing. Especially as I'm taking them to qld at the end of the year.

[04OFF]

Did you just have speaker playing music? Or did you play a propper dB?

The dB im relating too is a basic measure of sound , so my dB meter tells me how loud a sound is in decibels.

The speaker i used was a subwoofer (under 400 Hz) because low frequencies are great at traveling through walls, so Bass can be the most annoying for anyone else not watching a movie , i.e your nieghbours.



I found high density products, performed best in my application, none that i used are suitable for car accoustics, so no point talking about then, but the test method/s are still very valid.