Tuesday, March 16, 2010 - 08:05 pm, by: Nathan Hlad(Jackpot)
yeah i have 2 12" subs and you cannot hear a thing outside if you have the windows up. but i completely covered my car with the stuff.... my spare tire compartment rattling used to make me look like a tool when i cranked my system, but not anymore i look like a tool now because im almost 20 and i still wear a new era flat brim hat lolol
Tuesday, March 16, 2010 - 08:39 pm, by: Warren Moore(Warreng)
ey watup gangsta
so you mean you cant hear any of the rattle from the outside of the car. can you hear bass though? did you notice a louder bass with dynamat installed? see im looking to get 2x 12" L7 kicker subs so I want that really heavy bass. I thought boot rattle was hip? I thought that's what subs were for, to shake the out of your car like in this vid. http://www.youtube.com/watch?v=awDzd_z6L90
Wednesday, March 17, 2010 - 03:06 am, by: Nathan Hlad(Jackpot)
aww those rims are so sick ! and today i learned something, i always thought commercially made subs only went up to 15's but i guess they make 18's now, or he's lying. you would need an s.u.v to fit 18's in anyway lol and warren with the windows up you cannot hear a thing outside the car, and no i didnt notice louder bass.
Wednesday, March 17, 2010 - 04:03 am, by: Andrew Duaso(Andrewd)
I know a guy who put 4 18's in his car. Let me tell you with 4 15's the bootlid was about to rip off lol it was funny. I never heard what happened though probably burnt down or something or caused an avalanche.
I have 2 12's in my soarer. They work just fine for me
Wednesday, March 17, 2010 - 01:10 pm, by: Warren Moore(Warreng)
i dont believe you cannot hear anything from outside the car, even with subs pumpin. surely you would hear some bass. can you make a video for me opening and closing the doors and trunk nathan?
Wednesday, March 17, 2010 - 04:11 pm, by: Nathan Hlad(Jackpot)
sure warren when i get my car back, at the moment my soarer is in a deep sleep trying to get clean enough to get un-defected again ! but bro i assure you you cannot hear ANY bass or other sound for that matter when the car is sealed.
Tuesday, April 06, 2010 - 04:34 am, by: Nathan Hlad(Jackpot)
no david i didnt do the number plate to cover it in dynamt would be illegal as you wouldnt be able to see it. not too sure how many square meters but it cost me just over 2k all up without labour.
Tuesday, July 06, 2010 - 09:22 am, by: Marty Price(Fhrx)
A few people have asked me yo comment on this topic seeing as we go through tons of deadening here each month. This is an article I wrote for INCAR magazine a few years ago:
Ever visited a cinema with no carpet on the walls? Ever wondered why most home theatre walls have curtains? Maybe you've seen a car or jet test cell without diffusers on the walls? What about a radio studio or sound recording booth without diffusers? No? Starting to notice a pattern? Sound deadening and diffusers are fundamental cornerstones (and arguably one of the most important aspects) of any sound system. They're so important in fact, that they should be budgeted for long before the speakers themselves are. However before we delve into the wonderful world of what sound deadening and diffusers actually do, let's first take a step back and look at what sound actually is.
Simply put; sound is differing frequencies of pressure waves. Expanding that concept a little; when sound is created in a medium (i.e. it cannot travel through a vacuum) it's in the form of a mechanical wave. This wave is the result of back and forth vibration of the particles that make up this medium. As sound waves move through air the particles are displaced both right and left as the energy of the sound wave passes through it. The motion of these particles is parallel to the direction of the energy origin and this phenomenon is why we characterize sound waves in air as longitudinal waves. A speaker cone is designed to create such a longitudinal wave. As the cone moves back and forth it pushes on neighbouring air particles. The forward motion of the cone pushes air molecules horizontally to the left while the backward retraction of the cone creates a low pressure area allowing the air particles to move back to the right. This movement creates regions in the air where the air particles are compressed together and other regions where the air particles are spread apart. The high pressure regions are known as compressions and the low pressure regions are known as rarefactions (note; not refractions - that's to do with light waves).
Wavelength (also known as path length or soundwave length) are common terms when talking speakers and physical sound. Wavelength is the distance the aforementioned disturbance travels along the medium in one complete wave cycle. However at this stage there is a small differentiating factor that should be explained and that's the difference between transverse and longitudinal waves. For traverse waves this pattern occurs once every wave cycle and is commonly measured from one wave peak to the next adjacent wave peak (or from one wave valley to the next adjacent wave valley). Since longitudinal waves do not contain peaks and troughs, their wavelengths must be measured differently. A longitudinal wave consists of a repeating pattern of compressions and rarefactions. Therefore the wavelength is commonly measured as the distance from one compression to the next adjacent compression or the distance from one rarefaction to the next adjacent rarefaction.
When speakers move backwards and forwards they do so many times a second. Each time the cone does one complete movement forward then backwards then back to the zero point it's known as a cycle or one hertz (a.k.a. 1Hz). If the speaker undertakes one thousand of these cycles per second it is known to be playing 1000 hertz or 1 kilohertz (a.k.a. 1000Hz or 1kHz respectively). Music is the repeating pattern of these high and low pressure regions in various frequency orders and certain patterns of frequencies our ears interpret as harmonious. This harmony is simply the music you're listening too. The Pinna (the outer ear skin section) catches these waves and directs them into our ear canal which houses our ear drum. The ear drum then mimics these varying pressure waves and lets your brain know what its hearing.
Now you understand the basics of how sound physically works so let us move to the sound deadening itself. As speakers move in alternating directions the sound emanates from both the front and rear of the cone. The front wave is heard by you while the rear wave is what the sound deadening and diffusers deals with. With all due respect; your cars doors are glorified metal cans. They echo and reverberate inside and the skins flex easily, causing bass to become blurred and muddy and even to cancel itself out all together. I usually explain it by using the following analogy. Imagine you're seated in a boat in the middle of a crystal clear flat lake. One hundred meters away there is another boat floating idle. If you start gently rocking you boat, waves emanate from it. Pretty soon these waves reach the second boat and it also begins bobbing to mimic these waves. The problem is that as this second boat rocks it not only reflects your waves back but also creates its own. Your doors are the same in that the metal skins flex and create all matter of sound effects. These waves are only minutes or seconds out of phase (i.e. not even whole degrees) to the active wave and the result is that your ears get bombarded by literally hundreds of sound waves that are not supposed to be there. This creates an echoic effect and the end result is that the music sounds hollow and tinny. By adding sound deadening you're adding mass to the doors skins (like swapping the second boat for a cement pier in our analogy). This combats flexing its effects on internal sound waves.
Diffusers are absorbent pads that resemble foam or tiny egg cartons. These fight wave reflections and are placed directly behind the speaker. Remembering back to our boat analogy with the cement pier (deadening) now in place; while extra waves are not being created any more, the main waves will still be reflected. This is where the diffusers come in. We know from above that sound waves have a certain lengths at any given frequency. Somewhere within these frequencies is the perfect distance for sound emanating from the rear of the speaker cone to travel to the doors outer skin. This will then reflect and come flying back to impact the cone and cancel the next cycle. The diffusers catch these sound waves and trap them much the same way that the paint on stealth aircraft catches radar waves or submarines rubber skin traps sonar waves. The reason you need diffusers on top of the deadening is that most sound deadening has a smooth skin and hence still reflects sound waves.
Another vitally important aspect of achieving good midbass is to seal the speaker into the door. In nature all elements take the easiest path from origin to destination. Water is a good example of this phenomenon; you pour it out and it will run wherever the easiest path is. Air is the same. When your speaker cone moves forward, it creates a high pressure cell right in front of the speaker cone. If there is a high pressure cell in front of the cone then there will be a low pressure cell on the rear side of the speaker cone. If the door is fully sound deadened and the speaker is sealed on using sealant of foam gasket, the high pressure air will move out towards you with the end result being incredibly punchy and tight midbass from your doors. If there is no sealing (say the speaker is simply screwed down to the metal) and contains air leaks everywhere, the high pressure air simply takes the easiest path and moves around the edge of the speaker frame to behind the speaker where the low pressure cell is. In simple terms, you get no bass.
Many cars come with deadening from the factory but it is usually an insufficient amount, often only being a few inches here and there to minimise rattles during transit. Car manufacturers limit this deadening in order to keep production costs down. How much deadening you end up installing depends on your budget but both the inner and outer skin of your front doors should be fully deadened at least. You can always add more to the boot, floor and roof down the track.
In conclusion; for the serious sound enthusiast sound deadening is an absolute must. If you have a close look you'll notice the cars that sound the best in every continent (especially the ones that win the sound offs) are chock full of deadening. Sound deadening even helps factory speakers so get your self some today.
Tuesday, July 06, 2010 - 02:35 pm, by: Aiden Cheese(Chillpen)
That's a good write up.
Just as a testament, a friends toyota sera has a stereo installation which is potentially loud.. you know - ear distroyingly loud.
But his dynamat plasters the boot where the sub sits housed in his own fiberglass shell:
Basically the hundreds of decibel power sounds amazing from the inside, but outside it's barely more than a whisper. When he opens the gullwing doors though its another thing again
It's a pretty amazing setup really. Must be heard to be believed with how quiet it is while it's raging loud inside. Also we're midway through turboing the car (manifold is up, forged pistons are in, compression lowered, e-manage ultimate with a basemap, exhaust and turbo are going on soon).
Phil Gibson Goo Roo WA '91 UZZ31 track bunky, '94 blk/blk UZZ31
Thursday, August 19, 2010 - 08:51 pm, by: Nathan Richardson(Richtheblack)
I have just purchased a bunch of this stuff (Dynamat Extreme and Dynapad). I have all the interior out, cleaning the carpets (britex) and treating the leather with leatherique, fixing cracked plastic etc, and thought, hmmmm.... I might Dynamat everything, hmmmm... but what about the weight? Ah, hell it's not a track car!
I decided to do this mainly because of exhaust and transmission noise, but particularly the heat coming up through the floor gets unbearable!