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Alright, I finally decided what sub I'm going to get. I'm going to get an Alpine Type E 12" sub from Circuit City. 600 Watt max and 200 watt rms.



Anyway, Alpine's website makes the following recommendations:

Recommended Box Types : Sealed/Bandpass
Recommended Sealed Box Volume : 0.8 – 1.7 cu. ft.

Now, CC has two different boxes I can get that meet these specifications:

They have a $40 box that is sealed that is 1.00 ft^3


and they have a $90 box that can be sealed or ported depending on which plate you put on top that is 1.25 ft^3.


So both of these are within Alpine's recommended box sizes. What are the fundamental differences between a 1 and 1.25 cubic foot box? The cheaper one doesn't come with a gille, but the gill on the more expensive one doesn't look like it would protect it that much, either.

So which box would you recommend, or would it not make that much difference anyway?

I'm also going to get a 2-channel MTX amp that I can't find on their website. It's like $149 in the store. Is MTX a pretty decent company? The girl working there told me it's better than Audiobahn, Sony, and Pioneer as far as amps go.

Alright, thanks.

 
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Have a box built for the sub. It'll sound a whole lot better, and will cost relatively the same.

 
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Will be cheaper

 
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Not to mention a hell of a lot more fun

 
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that and don't get an amp kit there. my friend spent $90 to get an amp kit for his less than steller sony amp, 8 gauge. then i told him one could be had for less than half that price. that did the same thing

 
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I don't think he wants to build a box. Just get the first one and an extra grill. The second one looks like crap. Also, older mtx amps were better. Now they've gotten really bad. Oh and you'll prolly want a class D digital mono amp. Why did you decide on 12 instead of 10?Still a good brand of sub.

 
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You can have one built, meaning pay someone to build one, for the same price or less. It's not going to sound as good in a generic box as it would with a box built for the sub.

Also, why did you not take any of the suggestions on subs in your other thread? You can get a much better sub than this for the same money, or less. Why would you want a digital amp(class D) for an entry level sub? I'm telling you, you're wasting your money on this sub. It's an overpriced mainstream brand entry level sub. But, if you want to get it, by all means go ahead.

 
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Oh, and double deuce is right. Don't buy your wire from them. Go to an audio shop and buy it off a roll. It's much cheaper this way. The amp kits are overpriced. You can get the same wiring for about half of what you'd pay for an amp kit. Plus, they're likely to try and sell you some name brand such as scoche, or rockford wiring, which is marked up even more, when in actuality, wire is wire. As long as you get good RCA's, the power, ground and remote do not matter. So long as you get the size that will carry the current, it's going to sound the same.

 
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Correct. I don't have the time nor the resources to build my own.

Function over form. It's in my trunk so it doesn't really matter what it looks like. How much different would a 1 ft^3 box sound from the one that is 25% bigger? I assume that since they're both within the specifications listed from the manufacturer they'll both work.

When you say "have a box built for the sub," why? What criteria do they use to build the box? By saying this you are implying that boxes with different specifications will produce different sounds, which I am not doubting is true, but in my original post I asked what are the fundamental differences between two boxes of varying sizes for the same speaker when both boxes area within the recommended size as provided by the manufacturer? Why would it be advantageous to build a custom box for the sub when both of the ones I listed above fall within acceptable specifications as provided by the manufacturer?

The guy at Tweeter wanted $130 to build a custom box so I said no thanks.

What does class D mean? Mono amps are more expensive. I was told they can just bridge a 2-channel amp together and it will work fine. Is that just crap to get me to buy it? I ran this speaker through the amp in question at the store and it sounded fine to me.

Because they had 12's in stock They had this same sub at Tweeter when I went there, for the same price, surprisingly ($75).

Again, why? Both "generic" boxes are within the acceptable size range as listed by Alpine. Can someone explain to me how a custom box would be better? What formula is used to determine optimal size and shape? Are the materials in a custom box different? Instead of saying "custom = better," how about explaining to me why?

Because right now I don't have the time to be ordering stuff online or waiting for it to be delivered. I won't buy a sub without hearing it first and there aren't a lot of car audio stores in my area.

Where do I find an "audio shop?"

I wasn't planning on getting any of their more expensive wire, but good advice

 
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A box built to the specs of the sub take into account the optimal operating range for the sub. They give you measurements that it will work in. It may not perform to it's full capability, if still built within their provided specs, but it will operate. Contacting the manufacturer will give you the optimal operating range/size for your driver. It especially applies in a ported box. When you have frequency tuning, etc coming into play. Another issue is available space. Sealed enclosures, in theroy, provide you with the best transient response. Ported can achieve good transient response as well, but not as good as the sealed enclosure, an exception to this are ported enclosures with Qtc's greater than 1.0. In terms of efficency, the sealed enclosure ranks among the worst, generally speaking. Sealed or ported will generally reproduce mid-bass transitions the best. No enclosure type has a clear advantage. The only way to determine which type of enclosure is best for your application is to anaylize the characteristics of each. That said, generic enclosures are designed to a general set of specs, that cover a broad range of drivers, as opposed to using the optimal operating ranges for the specific driver you want. Another thing, the second example/sample box you gave can be either "ported or sealed, depending on which plate you put on top". Should you decide to get this one and want a sealed enclosure, it's not a true sealed enclosure. Air can escape at this plate. Should you decide you want a box built for your sub, this place will build you one (if you don't want to support your local shop): http://www.gnomeaudio.com/

I also answered another of your questions in my post prior to this one. Class D amps are sometimes called digital amplifiers. There is really no such thing today as a digital amplifier. A Class D amplifier uses transistors that are either switched on or off to represent positive or negative values. The transistors are either on or off. The advantage of such a system is that it is highly efficient and generates very little heat. The disadvantage is that there can be a distortion caused between the switching of the positive and negative transistors as the positive and negative transistors can not be on at the same time.
Many Class D amplifiers are finding their way into Subwoofers. They are inexpensive to build and the logic is that the switching distortion is not important in a subwoofer.

 
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Popcorn has it pretty much down, however one more thing should be noted: generally, you want to go with the largest enclosure that the sub will work in. The smaller the box, the worse the low end response will be. Since your sub is recomended for 0.8-1.7, it will perform at its worst in 0.8, and its best in 1.7.

Getting a box built will also ensure (if the builder is good) that the box is made of real MDF (stronger wood than the particle board most likely used in that pre-fab box) is properly sealed to keep it from leaking air, and you can get any color carpet put on it that you want.

Look into local custom shops, they should charge less than Tweeter and usually do a better job.

 
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I think your setup will be fine. Just to reiterate some of the other people's posts:

Don't buy a wiring kit there. If you're going to keep your stock HU, an entire wiring kit is pretty useless, especially since you'll probably be tapping the rear speakers for the signal. You won't need the RCAs that the kits come with. All you need is a power wire from the battery to the amp, a short ground and an inline fuse close to your battery. You'll need some thinner wire to connect the signal and connect to the sub. I think 8 gauge is probably more than enough for you. Some 8 gauge ring/spade connectors will finish it off

As for subwoofer boxes, the larger one should be better, better power handling and possibly low end response, but for $50 more, I wouldn't worry about it. The sealed/ported plate seems very gimmicy, and can leak air, all while not providing enough volume should you use the ported option. Typically, a ported sub will need significantly more airspace when ported compared to the sealed counterpart. If you want to try, you can put in some polyfill and see if you like the sound better. http://www.win.net/audtatious/audio/fiber.html According to the tests of that site, some polyfill can increase the apparent volume by up to 40%.

The amplifier, a Class D isn't necessary. It might be cheaper per watt, and draw a little less power, but if you want to keep your options open, stick to a Class A/B. I think technically it might have better sound quality versus Class D, even in the case of a subwoofer. Whatever MTX you're looking at should be fine.


Goodluck! And if you want help installing, I'm here If you decide to order online, it should be cheaper. Also, are you doing anything for the front speakers? If you plan on doing something, it might be worthwhile to get a 4 channel amp to power the fronts.

GL!

Ed

 
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All the guy wants is a sub in a box so he can hear the bass notes in the music that weren't there before. You guys up there know alot obviously, but I don't think it's that important to him. He just wants something that sounds decent without spending alot.

 
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^ Thank you.

Ed, about a week ago I upgraded the front speakers to some Pioneers. They have even less bass than stock, but but mid and highs that they produce sound awesome - much more clear and brilliant than stock.

 
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I wouldn't recommend their Road Thunder line, though.

 
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Ha I wouldn't recommend any of their new amps. Make sure you get the warranty.

 
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Ooh, yeah, right, I knew that