Philosophy behind sound deadening?

[Trendkill 10+ year member]

Everytime I see someone post their sound deadening work, they seem to put so much attention into getting every nook and cranny in a door, but then ignore everything adjacent to the door. It seems to me that if adjacent panels to the door can get away with zero sound deadening, then 100% precision isn't needed on the doors.

It also seems to me that you would benefit more from deadening the full radius around a speaker, even if that includes adjacent panels, than you would deadening the entire panel that the speaker resides in. For example in the image that I made below, I would think that option "B" would be more efficient use of the same amount of deadener in option "A". Ofcourse, I have no clue what I'm talking about so this is all a stab in the dark for me.



So what is the general idea behind deadening? Are you trying to "seal" the sound in/out? That wouldn't make much sense because if you are just doing the door, theres still plenty of area for sound to travel. Or maybe it's just a "surface area percentage related to the distance from the speaker" thing? Are you just trying to kill as much of the vibrations as possible?

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[audioholic 5,000+ posts]

If I were a sound deadening mat, my philosophy would be 'I stick, therefore I am'.

 

[CaliforniabOY5 10+ year member]

i just do the nook and cranny of the entire car.. . that way you don't have much to worry about.

 

[germanyt 10+ year member]

I have 250 sq ft of deadener in my car and I think that the more the better. I didn't focus too much on placement just as long as I got good coverage. There are web pages with instructions on where to put deadener but I think that if you are only going to cover 50% of the car then it doesn't matter too much where you put that 50%. IMO.

 

[Propimp 10+ year member]

look up sound deadener showdown. If you havent already

 

[Tonyguy 10+ year member]

but isn't the door typically sealed off from the body i.e. around the kick panel?

 

[audioholic 5,000+ posts]

A is by far the better option. Do not forget, you are not only trying to deaden rattles, the door itself is working as a baffle to isolate the front and rear waves from the speaker... it must be sealed to work properly. Even in your example picture you can see in option B there are large holes in the door that are left open, allowing rear waves to escape and cause cancellation issues.

Furthermore, the door is fairly isolated from the body in the front kick area shown to be affected in figure B. The door is connected by upper and lower hinges at the front, a locking mechanism at the rear.... and is cushioned around the whole thing with a heavy rubber gasket. Its solid and cushioned. Therefore, even in terms of rattles, you are much better off doing the entire door effectively, and leave surrounding body areas alone, provided that's all your budget/time allows.

 

[MiniVanMan 10+ year member]

The more density around the baffle the better. However, to avoid ringing, you deaden the rest of the door as well. So, by the time the vibration gets to the edge of the door, the amplitude of the vibration is greatly attenuated.

 

[Rudy 10+ year member]

The more density around the baffle the better. However, to avoid ringing, you deaden the rest of the door as well. So, by the time the vibration gets to the edge of the door, the amplitude of the vibration is greatly attenuated.

Exactly. Then you focus on adjacent problems as needed.

 

[Propimp 10+ year member]

^^ THERE HE IS i KNEW HE WOULD POP UP SOONER OR LATER

 

[headless 10+ year member]

What do you guys use to clean your doors off? I figure you'd want to use something that is aggressive on grease and dirt but nothing that would leave a residue? I was thinking maybe acetone.

 

[Rudy 10+ year member]

^^ THERE HE IS i KNEW HE WOULD POP UP SOONER OR LATER

Setting traps? //content.invisioncic.com/y282845/emoticons/laugh.gif.48439b2acf2cfca21620f01e7f77d1e4.gif

 

[Trendkill 10+ year member]

A is by far the better option. Do not forget, you are not only trying to deaden rattles, the door itself is working as a baffle to isolate the front and rear waves from the speaker... it must be sealed to work properly. Even in your example picture you can see in option B there are large holes in the door that are left open, allowing rear waves to escape and cause cancellation issues.
Furthermore, the door is fairly isolated from the body in the front kick area shown to be affected in figure B. The door is connected by upper and lower hinges at the front, a locking mechanism at the rear.... and is cushioned around the whole thing with a heavy rubber gasket. Its solid and cushioned. Therefore, even in terms of rattles, you are much better off doing the entire door effectively, and leave surrounding body areas alone, provided that's all your budget/time allows.

Ok I can definately dig the fact that the door is somewhat isolated due to the hinges/weatherstripping. But as for using deadener to seal the speaker off when you are making custom pods, the pod itself should be sealed anyway right? I realize the image I made suggests that it's a stock speaker location, but I'm asking now.

Now what about this situation: The panel that your sub box is sitting on is 25% (arbitrary number for argument's sake) more rigid than your front floor panels. Both panels do resonate. You only have enough deadener for one area and don't feel like spending more money. Which is more important: the area near the box, or the less rigid area away from the box?

 

[wesl56 10+ year member]

yeah... bang on your door... even at the bottom... the entire door panel vibrates, but the floorboards dont... sorta works like that thats how i do when im deadening... just keep tapping around and add more where you sense vibrations

and i just use rubbing alcohol to clean before i apply

 

[audioholic 5,000+ posts]

Ok I can definately dig the fact that the door is somewhat isolated due to the hinges/weatherstripping. But as for using deadener to seal the speaker off when you are making custom pods, the pod itself should be sealed anyway right? I realize the image I made suggests that it's a stock speaker location, but I'm asking now.
Now what about this situation: The panel that your sub box is sitting on is 25% (arbitrary number for argument's sake) more rigid than your front floor panels. Both panels do resonate. You only have enough deadener for one area and don't feel like spending more money. Which is more important: the area near the box, or the less rigid area away from the box?

Yes, if you are running a sealed speaker pod, sealing off the door is no longer necessary. Then its just a matter of vibration dampening, but I feel my comments about a rigid door with weatherstripping all around it is isolated still holds true.
Most people dont run small sealed pods in the door due to the fact it will tend to hinder low-end output from most drivers. An aperiodic enclosure is used sometimes to retain the small enclosure with the benefits of an IB space, but then sealing the door becomes needed again.