Check out my idea,

[75MonteCarlo 10+ year member]

Ok here's my idea.. we know that spl is the pressure level created in a car's cabin right, so we need a way to move more air, in order to get more pressure. We know that 2 12" subs are going to move a certain ammount of air, based on the level of exursion and force with which they move. Here's my thought, what about using the pressure created by a pair of 12's to move a much larger plate, which would in turn move a much greater ammount of air on its own? In my design, I thought of using a large acrylic window mounted to a rubber surround on one end of a sealed enclosure.. the subs would create pressure inside the enclosure, and the pressure would force the window to move back and forth with the subs. However, the window would have a lot more surface area, and therefore should be able to move more air and increase our SPL level.. BUT i've thought of some problems with this idea:

1.) Air acts like a spring, so the window is not going to move with as much force as the subs do.

2.) The window will not get as much excursion as the subs, because the window has a greater surface area than the subs.

3.) The rubber surround may actually cause the window to absorb energy instead of increase the spl level.

Here's a pic of my idea, tell me what you guys think.. could this, would this, work?//content.invisioncic.com/y282845/emoticons/uhoh.gif.c07307dd22ee7e63e22fc8e9c614d1fd.gif

Click to read more...

 

[JimJ 5,000+ posts]

Conservation of energy. You're not going to get more out of it than you put in, and I bet acoustically coupling a really large acrylic plate is going to be inefficient as hell.

Plus, it would most likely be banned from any competition organization.

 

[squeak9798 5,000+ posts]

Yeah...I see a ton of problems with the idea, the main ones jack outlined. Your going to lose energy in the "conversion" process, first and foremost.

 

[squeak12 10+ year member]

Thats an odd looking picture before you zoom in...

 

[JimJ 5,000+ posts]

You want to move a ton of air, don't dick around, get a Parthenon and a 48" square baffle //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[75MonteCarlo 10+ year member]

I know you can't get more out of it than you put in, but how can we increase the efficiency of the woofers? If we could just turn electrical energy into sound energy with no loss of efficiency in the conversion, a hell of a lot could be done with a tiny ammount of power.. But as it is we lose a LOT to mechanical movement and heat production of the sub itself, and then of what we do get to turn into acoustical energy, we lose through absorbtion, distortion, vibration, crappy enclosures, leaks in the vehicle, etc... What can be done to maximize a pair of 12's, short of a tcab box? ..lol

 

[75MonteCarlo 10+ year member]

You want to move a ton of air, don't dick around, get a Parthenon and a 48" square baffle //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

Wtf is a Parthenon? I'm guessing a motor assembly that you can put ur own cone substitute onto?

 

[JimJ 5,000+ posts]

The best link eludes me ATM...Google "Adire Parthenon" and see what comes up...

Basically, it's an extremely high excursion linear piston driver...basically a subwoofer without the traditional basket and surround.

 

[LoudCrownVic 5,000+ posts]

Adire audio makes it. It's a dipole driver that is basically just a 48" plate hooked up to a big mofo motor (no spider) and it has 12" or more of excursion.

How exactly it makes sound is beyond my knowledge... But yah, the woosh sound you hear when a big sheet of mdf falls x1000=hella ballz.

 

[LoudCrownVic 5,000+ posts]

You are talking like a passive radiator setup, which has been done.

Really, a cheapass way to win audio competitions would be to get the resonant freq of the vehicle and the box tuning to match...

 

[imaspaceguy90 10+ year member]

I think u may have something here. SOunds very scientific to me tho, but more air does cause mroe bass

 

[JimJ 5,000+ posts]

For SPL, it's not simply the volume that matters.

You also have to take velocity into account.

 

[MemphisSoul4U 10+ year member]

The last thing I heard on the Parthenon was it could be made into any size/VC config driver you wanted (with a $1500 non refundable deposit). The 48" plate was for a demo. It hit like a 13x-ish (can't remember how many watts was to it, but I do remember it was a very low number)in an open room bolted to a stand (no box). Not sure exactly what it was, been a long time since I read up on it.

 

[Venom 10+ year member]

Look into hydrolics and try to use that similar principal...forse applied to a small area = greater force applied to larger area...but you would have to use some sort of fluid between the "cones", some way to completely seal the gap and remove all air bubbles...lot of $$$ for something that is impractical, but theoretically could work...

 

[75MonteCarlo 10+ year member]

i can't find much on the parthenon, but no this isn't a passive radiator.. passive radiators use the rear of cone pressure in a sealed box.. in this im talking about using the pressure wave from the subs to act like an air piston and move a large plate.. but then yes, it occured to me that i'd lose velocity with the larger surface area..