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BigGuy

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edub : what is your problem with those subs ? I don't care if they are a copy of this one or this other sub, as long as they perform well and are at a price I can pay !

All the bulders tell you they are different but you're still talking !

I quit.

Sorry !

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Someone please explain why true "spl" drivers don't need big power. Everything I thought I knew about car audio needs to be reevaluated. Wow???

High sensitivity means less power required to get loud. Most SPL drivers have a higher sensitivity.

Pretty misleading statement and really not in context in a car audio centric forum. When a pro audio guy starts talking about an SPL driver he's talking about a driver for sound reinforcement like a concert stack. The T/S sensitivity spec is for output @ 1kHz and for the frequency range desired for his application, a higher number there makes sense. The equation for getting that is pretty easy as well: large, light cone; light coil; minimal suspension; big motor. At higher frequencies, long excursion isn't critical. A 10mm Xmax is huge for those drivers. At 1kHz, sensitivity boils down to little more than (cone area x motor force) / (moving mass x suspension resistance).

Compare that to a low frequency SPL driver as imagined by a car audio guy. For that kind of driver, 1kHz sensitivity means little because at lower frequencies, excursion means everything. To get low freq SPL, you have to move a lot of air, so swept volume matters. Additionally, the cone damping provided by the enclosure places huge stresses on the cone. That means that the cone has to be made heavier to withstand the strain. To counteract that heavier cone, you have to increase the strength of the motor so the coil gets heavier. You find yourself in this terrific catch 22: to get louder, you must increase mass which keeps you from getting louder. Going with a ported enclosure can reduce some of the need for Xmax and allow the coil to be shorter(and lighter), increasing BL right around the center point, but then you have to consider the cooling needs of a motor that is moving very little (and increase mass to compensate) and the incredible strain that is put on the cone and cone/former junction (and increase the mass to compensate). The result is a heavy driver that in fact DOES need a lot of power to get loud.

There are large drivers in use in the car envirionment that have high sensitivities. Some of them are subs and they can often get pretty loud without a lot of power. That said, they are not the drivers that you see competitive in SPL comps. They simply cannot handle the rigors of generating very high levels of SPL. The reality is tha the qualities that lead high sensitivity in the middle to upper frequencies are not the qualities that you want in a lower frequency driver, especially one that you want to get really loud.

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Reminds me, I need to email that website to correct them on some info.

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