A lot of people spend a massive amount of time and money building their Car Audio Systems to get the perfect (perfection is really subjective though) sound only to find a new rattle when upgrading to bigger/better equipment. I personally have come across this issue myself in several cars I have owned, on some cars it was just a minor bit of road noise and slight number plate rattles but since my systems have gotten bigger the rattles grew and so did the annoyances of it!
There are three main uses for Sound Deadening, these three uses are: Increasing Sound Quality, Reducing Road Noise/Reducing Rattles and Increasing SPL.
Sound Quality will always be something I will always seek in Car Audio and in my opinion will always be the one thing that can always be improved. For instance changing speakers can make a massive difference but installing Sound Deadening will make even more of a difference, sometimes so much of difference that comparing a set of speakers before Sound Deadening and a different pair after Sound Deadeningwould be totally unfair.
In my opinion there is nothing worse than installing some brand new speakers into your car to find a new Rattle, Rattles can be just a small annoyance but after a period of time they will get worse to the point of not being able to fully enjoy your music unless it is at an insane (insane to people of norm) level. Adding Sound Deadening to your car is a sure way to reduce Rattles and Road Noises at the same time, in most cases up to 90% of your cars Rattles and Road Noises will be reduced by installing Sound Deadening.
Believe or not if you compete in Sound Off’s (dBDrag etc) having Sound Deadeninginstalled into your car can improve your SPL (Sound Pressure Level) score, in some cars obviously more than others. In my instance I was getting a constant 154.8dB with a single 18″ Sub-Woofer and was at the point of zero gains, this was due to waiting to get to this point before Sound Deadening as we wanted to know the difference it was going to make at this level. To our surprise we had a .5dB increase, it might not seem like much but to get even a .5dB over the 150dB mark is a massive increase!
Another good use for Sound Deadening is on a sports cars that didn’t come Sound Deadening due to weight reduction. A lot of people make the assumption that allSound Deadening weighs a ton, this however isn’t entirely true! For instance DynaMatmake a light-weight version called Dynaliner, Dynaliner has similar properties asDynamat but with a reduced weight giving you the best of both worlds so your sports cars power-to-weight ratio won’t be sacrificed so much with the smooth quiet ride of a luxury car!
There are a lot of companies that make Sound Deadener out there and I have tried a few of them, the one that has stood out over the years would be DynaMat & its also one of Sound Deadening companies that hasn’t disappeared over the years too, which is a good sign that a company makes a good product if it has past the test of time!
source: http://abtec.co.nz/blog/the-benefits-of-sound-deadening-in-your-car/