If that stuff could be used for somethin like that.. and don doesnt' know.. i can only imagine how many layers it would take to prevent pressure from escaping.

It would be easier to just create a shell inside your trunk and build your design from within.

Generically speaking, it only takes mass to block sound waves. Depending on what frequency and what energy will determine the amount. Lead sheeting is the most obvious tool for this, but MLV is a cheaper alternative which is why it is used.

As for your SPL question, there are a ton of things that you can do to both the structure to either help or hurt as well as the acoustic space. No "rule of thumb" though as every application is specific.

Good advice. Thanks Don.

*surprised Ant didn't help...oh wait, he wasn't going to get a sale so of course he wouldn't*

Some people are worth doing business others aren't. If you don't know Rudy owns SDS and is the most helpful deadener voice on the web. If you haven't bought your vinyl look at what he has, it is priced competitive and unlike everywhere else his interest is in helping you make your car quiet. If you have just remember that for next time.

Wow..

Was there a reason you chose to insult my integrity in a public thread that had nothing to do with me or my products?

I am not sure what to make of an SSA moderator publicly insulting a vendor of the forum out of the blue like this?!!

Dissapointing.

Either way, I too would suggest Dons product when it comes to raw MLV. His prices are good and the quality seems to be perfoect for automotive applications.

No reason not to use it if trying to reduce unwanted airborn noise.

ANT

It also depends on what your goals are too..

I never seen the purpose of using it in this thread either.

I am an spl competitor so deadening material is a big no-no if you want high numbers on the mic.

If it's not for competition and just for musical enjoyment then it's fine.

I just know lots of people on here who may not compete tend to do so eventually with the same car they had when they first became a member.

Competing with lots and lots of sound deadening material will only hinder your potential in spl competition.

It's not talked about much on here but it's true in lots of vehicles.

So all those guys like Alan Dante who have lined their vehicle with concrete aren't sound deadening the vehicle ??

SPL isn't my forte, but most of the extreme competitors I've seen put a lot of time and effort into solidifying the "shell" of the vehicle...clamps to hold doors shut, concrete lining, bracing...all the way to friends sitting on roofs and windshields during scoring. I would say this contradicts the idea that sound deadening in SPL is a big no-no...it also fails the logic test; panels vibrating are absorbing/expending energy that could have otherwise been spent pressurizing the airspace. Why stopping this would be a bad thing simply doesn't make any sense.

sound deadening material does not qualify for concrete... I thought that was clear but i guess it wasnt..

You don't go to secondskin for concrete do you?

Concrete will\should increase resonance...

Deadener materials will decrease resonance which will hurt the goal of higher pressure levels.

This topic DOES NOT consist of this argument so if u want to talk about it, create a topic about it.

You didnt understand what i said.

I am around enough competitors and do our own research to know what's what with different installs to see what helps in pressure levels.

The thought of actually using sound deadener to help with SPL is a no-no in most applications. As i said earlier, this type of materials lowers resonance.

You want to debate me on this, i'll throw this topic over on another forum where many competitors are and will let them give you the detailed info on it since they been doin it a LOT logner than i have.

The percentage of people making acoustical mods to their vehicles who end up doing SPL competitions is minuscule. Among those who do, a good number use their vehicle as a daily driver and are willing to make some concessions so that the daily experience is not excruciating. In any case, the OP has decided he wants a barrier to use in his car so the recommendations I made in this thread are based on the assumption that a grown man can be counted on to know what he wants.

Blanket statements about sound deadening materials resulting in a net gain or loss of SPL need to be looked at very skeptically. I've seen a roughly equal distribution between "I applied product X and gained a dB or 2" and "I applied product X and lost a dB or 2". That's because every panel and every vehicle is different. Two things happen to influence the outcome when you apply a vibration damper to a panel - some sound energy is going to be converted to heat and the panel is going to be made somewhat less susceptible to distortion. Whichever mechanism dominates is going to influence the end result and I think determining the outcome ahead of time is well beyond most of our capabilities. I'm inclined to agree that any vibration damper that claims to enhance SPL is iffy at best. Take a look at the graph Dynamat uses to support this claim sometime when you need a laugh.

It's absolutely wrong to think you can get more energy out of a system than you put into it. If the panel resonates at a useful frequency you will be better of than if it didn't - all else being equal but you still have to put more energy in than you get out as resonance. As has been pointed out above, the only modification that makes sense for pure SPL goals is reinforcement without vibration damping. Damping "wastes" energy as does panel deformation.

x2, i agree

It's absolutely wrong to think you can get more energy out of a system than you put into it. If the panel resonates at a useful frequency you will be better of than if it didn't - all else being equal but you still have to put more energy in than you get out as resonance.

Exactly, but if the resonance is at a useful frequency and phase you wouldn't want to dampen it and either way you are going to have it being absorbed/wasted.

sound deadening material does not qualify for concrete... I thought that was clear but i guess it wasnt..

You don't go to secondskin for concrete do you?

Concrete will\should increase resonance...

Deadener materials will decrease resonance which will hurt the goal of higher pressure levels.

This topic DOES NOT consist of this argument so if u want to talk about it, create a topic about it.

You didnt understand what i said.

I am around enough competitors and do our own research to know what's what with different installs to see what helps in pressure levels.

The thought of actually using sound deadener to help with SPL is a no-no in most applications. As i said earlier, this type of materials lowers resonance.

You want to debate me on this, i'll throw this topic over on another forum where many competitors are and will let them give you the detailed info on it since they been doin it a LOT logner than i have.

You are confusing deadening/damping in general with specific sound deadening products.

You don't even understand you said, apparently.

geez i go away for a weekend and my thread blows up. lol

thanks for the info guys, continue your discussion if you like but my question was answered.

Good advice. Thanks Don.

*surprised Ant didn't help...oh wait, he wasn't going to get a sale so of course he wouldn't*

Some people are worth doing business others aren't. If you don't know Rudy owns SDS and is the most helpful deadener voice on the web. If you haven't bought your vinyl look at what he has, it is priced competitive and unlike everywhere else his interest is in helping you make your car quiet. If you have just remember that for next time.

Wow..

Was there a reason you chose to insult my integrity in a public thread that had nothing to do with me or my products?

I am not sure what to make of an SSA moderator publicly insulting a vendor of the forum out of the blue like this?!!

Dissapointing.

Either way, I too would suggest Dons product when it comes to raw MLV. His prices are good and the quality seems to be perfoect for automotive applications.

No reason not to use it if trying to reduce unwanted airborn noise.

ANT

Out of the blue, my ass. You can buy your way in many places in life, but my respect isn't for sale.

Do you really want to do this here? If you want to fine continue on, you'll clarify it enough for all of us.

I can always count on you to speak your mind. lol.