Whats the Sd of my L7s?

[Nukedsodapop 5,000+ posts]

I was wondering today what the Sd of my Drivers were (12") and how close to the Sd the 15" round drivers are, are they close? And I also have another question to be answered after that one... Thanks

Blake

P.s. I couldnt find it in the manual at the kicker website for my model...

Edit// Nvm, I found it... I guess it would be the same as the new models right?

the number I found is 0.0645...

How close is that to 15's?

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[Goldtaz1 10+ year member]

I was wondering today what the Sd of my Drivers were (12") and how close to the Sd the 15" round drivers are, are they close? And I also have another question to be answered after that one... Thanks
Blake

P.s. I couldnt find it in the manual at the kicker website for my model...

Edit// Nvm, I found it... I guess it would be the same as the new models right?

the number I found is 0.0645...

How close is that to 15's?

In terms of centimeters^2 that is equal to 645. If you look at the L7 12 in comparison with a typical 12" round driver, the Sd of a typical round driver is 420 cm^2. As you can see, there is quite a difference between an L7 and a round driver. A typical 15" round driver will have somewhere around 810 cm^2 of Sd whereas an L7 15" driver has 1056 cm^2 of Sd. This is what makes L7's very tough to beat in SPL. Sheer cone area is a tremendous factor in moving a lot of air.

 

[Nukedsodapop 5,000+ posts]

thats what I was thinking, And Im guessing 18s have somewhere around 1200 right?

 

[Goldtaz1 10+ year member]

thats what I was thinking, And Im guessing 18s have somewhere around 1200 right?

Yep, mine has right at 1210 cm^2 of Sd. That's why so many big name competitors run the SOLO X 18, on top of the fact that it's hard to kill the thing.

 

[Nukedsodapop 5,000+ posts]

And what I was thinking was 4 L7s, which should be around 2,580cm^2

Either that or 4 15 L5s, but I dont think I have the space for that, even though Im planning on taking the whole trunk...

What would you go with?

 

[Nukedsodapop 5,000+ posts]

Also, My 4 12s woudl be about the equivelent of 3 15s correct? 810 x 3 = 2430 and 645 x 4 = 2580

And according to your MT, It would be about the equivelent to 2 18s? What about the excursion factor? Would 4 times the movement make it alot/less louder?

 

[Goldtaz1 10+ year member]

And what I was thinking was 4 L7s, which should be around 2,580cm^2
Either that or 4 15 L5s, but I dont think I have the space for that, even though Im planning on taking the whole trunk...

What would you go with?

In my experiences, you sometimes reach the point of diminshing returns. What I mean by that is sometimes more is not always better. You could begin to have cancellation issues, especially if this is going in the trunk of a sedan type vehicle. I believe that either (2) 15's or (3) 12's and for fact of the matter (2) 12's may be the best setup for a trunk. The thing that you definitely don't want to do is restrict the air flow (i.e. SPL generated) from reaching the windshield of the vehicle. If the system takes up the entire trunk then I am afraid you may/will loose SPL.

 

[Goldtaz1 10+ year member]

Also, My 4 12s woudl be about the equivelent of 3 15s correct? 810 x 3 = 2430 and 645 x 4 = 2580
And according to your MT, It would be about the equivelent to 2 18s? What about the excursion factor? Would 4 times the movement make it alot/less louder?

Yes, the (4) 12's would be right there with the (3) 15's.

As it pertains to the MT, (4) 12's would be just a tad bit more than (2) 18's (probably not really noticeable). The excursion factor is where a shitty woofer is separated from a good woofer. You would multiply the Sd X the X-Max to arrive at the full displacement potential of the driver. You will need the xmax parameter to determine full displacement potential, but xmax is not a very good indicator of SPL potential. Case in point is the Pioneer W5000SPL. It only has an x-max of like 11 mm, but the **** thing gets loud. This is in part because of the extremely strong motor structure and stiff spiders. SPL vehicles are meant to get loud at one frequency. This is where a strong motor structure and stiff spiders come into play. I'm pretty certain that the RE XXX series sub has better xmax potential than my MT, but I can guarantee you that if you put my 18 MT up against the XXX 18 in the exact same enclosure with the same exact power, my MT will walk all over the xxx 18 in SPL. In terms of musicality though the XXX will hand me my *** probably because it has better potential (xmax) to extend to the lower frequencies. Just food for thought.

 

[Nukedsodapop 5,000+ posts]

well the thing was, that the 4 12s would be in the back of the trunk, side by side, ported through the rear deck.... Would that be any problems?

 

[squeak9798 5,000+ posts]

but xmax is not a very good indicator of SPL potential.

For a daily setup; it's very pertinent to the conversation.

The thing you are neglecting to mention is that Xmax is only a linear figure.....how far the sub can excurt linearly. The reason Xmax doesn't pertain to SPL setups is because those setups are not worrying about linearity; all they care about is sheer output. That being the case, they are typically throwing the woofer to Xmech.

 

[Goldtaz1 10+ year member]

For a daily setup; it's very pertinent to the conversation.
The thing you are neglecting to mention is that Xmax is only a linear figure.....how far the sub can excurt linearly. The reason Xmax doesn't pertain to SPL setups is because those setups are not worrying about linearity; all they care about is sheer output. That being the case, they are typically throwing the woofer to Xmech.

Good call, I knew I was neglecting to mention something. Thanks for the help squeak.

 

[Nukedsodapop 5,000+ posts]

So, what would you guys go with

 

[Goldtaz1 10+ year member]

So, what would you guys go with

Go with (1) Crystal CMPx2 15" sub. I know just the place you can buy one.

http://forums.caraudio.com/vb/showthread.php?t=109580

//content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif !!

I would personally go with (2) 15's if that is within your means. (2) 15's just offer the best of both worlds; getting loud and sounding good doing so.

 

[Nukedsodapop 5,000+ posts]

my 2 12s do that, Im looking for more...

 

[Goldtaz1 10+ year member]

my 2 12s do that, Im looking for more...

Guess I should just start charging for my advice then. Look at the mathematical numbers above and tell me that (2) 12's are going to perform like (2) 15's.