Shallow subs...

06powerstroke

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CVR's are actually pretty decent subs. My dad has one 10 in his 08. If those CVR's are in a good sized box than these 3 10's may not get you much more sound. Not sure as I have never heard 2 CVR's, only one. I beat all my buddies dual Kicker setups but they have CVT's. Not trying to send you right back to square one I just don't want you to spend money on something that ends up sounding the same. This could easily be solved if you could just listen to my setup, lol.
 

SIX_OHH

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I wonder if i could call you. would it sound worth a crap? My cvrs are in a huge ported box but it took up the whole backseat
 

06powerstroke

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I wonder if i could call you. would it sound worth a crap? My cvrs are in a huge ported box but it took up the whole backseat

It will just sound like distortion. If the ported box frequency matches the CVR's I bet it sounds pretty good and loud, however you are taking up the back seat. If it was me I would go to the shallows just for the clean install, even if it's not much louder.
 

Worstenemy453

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I'll get you some pics of the setup smut.


I already said a good 8 setup can take a 12, but your making it sound like you can make any 8 as loud as a bigger sub. Which isn't true. You can beat the fact that more surface area will move more air. You say a 8 in a proper box will blow your mind, well just imagine a 12 with a perfectly tuned setup. Will take the 8 out hands down. Of course this is assuming you have the space for a box. Being that these subs are in the back of a crew cab 12's may be a bit out of reach...

How is the frequency of the box going to affect my amp's output? I agree that when dealing with a ported box the tuned frequency of the box is super important for good clean loud bass.

If you have your subs wired to 1.3 ohm nominal, that number actaully goes up because of the box. So with box rise, you might be at about 4-5 ohms reactive load after the box rise happens. Say in a ported box tuned to 32 hz and you have your subs wired to 2 ohms, when your music notes actually hit 32 hz, you will be the closest to your nominal 2 ohms, but during other frequencies, your amp will not actually be seeing 2 ohms, it will see whatever the reactive load will be, which can not really be caluclated. This happens in a sealed box as well, sealed boxes have tuning frequencies but that is manipulated by size and not port.

I wasnt saying an 8 in a proper box will always out pound a 12", im just saying that writing off 8"s because of their size isnt right. And in a space limited application where you could go 8" ported or 12" sealed, then i would be willing to be the 8" would sound better and hit harder. Of course equipment choice factors in to that as well. But if space is a limiting factor i would go with 2 8"s ported to around 32-34 hz.
 

Worstenemy453

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I guess I just don't see how the resonant frequency of a box adds resistance to my physical wiring.

I was trying to find a write up to explain it better than i can. In reality, most people wouldnt care anyway, its really mostly a competition thing. It wont make a break a daily system at all, just something that happens.

basically the only way to not hae your reactive and nominal load be different is to free air the sub.

Here are some quotes, and the link where they were found that would help explain it a little better.

Compression = impedance rise. Compression includes any kind of possible loadings such as corners or angles that would create turbulence. To lower the impedance rise, the enclosure must be designed more as a wave guide. On an aerodynamics standpoint, a low impedance rise box will have a Reynolds number of 2300 or lower. Just think about an aerodynamic car...low resistance, low impedance. Let me know if you need an even more detailed explanation.

Tuan

Your view of impedance rise is like many others who think that it will kill the performance and high rise equals low output. This is not true at all as these spots of high impedance are the resonant points of the system (the points of greatest efficiency). That is why a sealed box can have a flat response even with an impedance rise of more than 30ohms at certain frequencies and be back to 4 for others.

And if you want to make an enclosure with a very flat impedance curve, you have to build a correctly designed and tuned transmission line. Done correctly, they have very flat impedance curves but that doesn't mean that they're loud. It had much better benefits than that.

Alright I understand better now. Impedance rise is not everything and I am focusing to much on it. I thought it was alot more important than it really is. So basically high rise DOES NOT equal low output, its more a combination of rise and efficiency that determines a box's output characteristics.

http://www.caraudio.com/forums/encl...elp/442507-how-make-box-least-imp-rise-3.html

http://www.caraudio.com/forums/wiri...on-help/427166-how-stop-inpedence-rise-2.html

http://www.caraudioclassifieds.org/...-references/88695-box-rise-why-not-worry.html
 

SIX_OHH

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I get it now. It adds resistance because the speaker is fighting the air molecules instead of being free flow like they would be in a correctly sized box. That resistance transfers from physical energy to electrical energy causing a higher load at the coils...from the coils through the wire. Is that right?
 

Worstenemy453

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I get it now. It adds resistance because the speaker is fighting the air molecules instead of being free flow like they would be in a correctly sized box. That resistance transfers from physical energy to electrical energy causing a higher load at the coils...from the coils through the wire. Is that right?

Well even in the properly sized box it would still happen but not as bad. But i believe that would be a simple explanation of it. Sounds about right.

Most people that try to build the best boxes use Winsd Pro. A sweet program for designing. Also using aero ports insteal of slot ports gives you less angles inside which helps fight box rise and makes your port more effiecent itself since there is no hard angles meaning you can achieve more with less port area.
 

SIX_OHH

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06powerstroke...........idea...what do you think about a 12 in the center 2 10s on the outside?
 

06powerstroke

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06powerstroke...........idea...what do you think about a 12 in the center 2 10s on the outside?

I had a mix of 12's and 10's in my car once, didn't sound bad to me... My 10's hit well above 40hz, but any lower than that and they suffer. The 12 should be able to hit a little lower. I'm just now sure exactly how it will sound in a shallow application.
 

jdc753

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Box be damned output is disctated by cone area x power, and in sealed applications Xmax (cone travel) and in ported more box than it is xmax. Most shallow or any common/cheaper sub are not going to have much cone travel, maybe 10-12mm, while some other subs will have as much as 25mm, that can make a big difference when it comes to moving air molecules. Also size doesn't matter when it comes to "speed" larger subs are not "slower" than smaller subs, just another myth. The one thing that is true of sub size is with how much authority they can play on the low notes, the larger woofers will naturally have a lower F3 and be able to play down low easier and with more authority.


With all that said back on topic, in an 04+ crew cab truck I believe at best you will be able to get maximum 2.25ft^3 behind the seat, more realistically 2.0ft^3 with a maximum mounting depth of 5".


For the money I would run the Pioneer shallows, not the cleanest sounding subwoofer, but just all around good for the dollar for doesn't want a huge box like the Kicker CVT's want and not as expensive as the JL TW5 series or other more refined shallow mount subs.

With 60" maximum width across the back you could get 4 pioneer 12's back there giving each 0.5ft^3 a peice where they recommend at the smallest 0.3ft^3

The shallow sub I personally would love to try is the Stereo Integrity BM MKIII, its a shallow mount 12" that takes up to 500w RMS and a much different motor design that should sound super clean. I haven't heard it but I have its slightly older brother which is the same motor design and I am VERY happy with it, and expect the BM to sound just as good while shallower and need less space, hence giving me room for more subs :evil
 
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