I'd be going behind the seats. Is a shallow sub not needed? Also, that link was pretty informative, I'm a afraid I still don't really understand how everything works. Is it saying that if I have one amp and two subs, that it's better to hook up in series rather than parallel?

I was really just trying to get my feet wet with everything at first, but I've now just decided that I may as well dive in. I believe in "you get what you pay for", and I'd rather pay a little extra for quality than try and skimp here and there (I'm not trying to knock on your statement about saving money, I'm basically just saying I'm not quite educated enough to know EXACTLY what I need, so I'd rather make sure that I go a little overboard rather than risking going underboard). I also don't want to go to a stereo shop for several reasons: 1) They're gonna get pissed off once they realize I'm not buying from them and going straight to ebay. I hate doing that, but when your funding is limited to a part-time job, you gotta do what you gotta do. 2) They could possibly have nothing but ***** in their shop, and even if I went in there telling them money is no object I just want the best of the best, then they're just going to recommend the most expensive or nicest piece of ***** they've got on their shelf. They're not going to say "well we really don't have what you're looking for here, you probably should look for 'this and that brand/model'." I mean the stereo shop I would go to is extremely reputable, and they know their stuff...but they're still salesmen.

But I pretty much know that I'm going with Rockford Fosgate subs, simply because I know they have a good name behind them and they're awesome quality. So based on me wanting to put (2) 10" subs behind my back seats and run them both off one good quality amp, what would you guys recommend to look for as far as the specs go for the subs and amps. I'm going to run this box: Ford F-250/F-350 Crew Cab 99-07 BTS Dual Subwoofer Box - Subwoofer Box | Subwoofer Enclosures | Car Subwoofer Boxes and Truck Subwoofer Boxes at SuperCrewSound so if I don't need shallow subs then great. I just assumed I would based on the limited space.
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Neither. The sensitivity is far too low for my taste. I'd recommend something 90db or above. You're looking at and 83db rating for those subs. For a comparison, the Pioneers I'm going to install have a 93db rating. Simply put, your amp would be working harder to push the Fosgates than it would the Pioneers. The higher the sensitivity, the less power it takes to a achieve a given db.

RMS power is what to look at. It doesn't have to equal the RMS handling power of the sub, but it shouldn't exceed it. It can, but then you'll just have to set the amp gain lower.

I would also be looking at a class D mono subwoofer amp, not a 2 channel A/B. The class D's are designed specifically for subs, are much more efficient and use less power than an equivalent class A/B.

As far as impedance, since you're going with 2 subs, I'd keep it simple and get 2 single voice coil 4 ohm subs. Wire them in parallel for an impedance at the amp of 2 ohms. Just be sure the amp you get is 2 ohm stable. Wiring in series would increase your impedance to 8 ohms, which I wouldn't recommend. The amp would be working way too hard.

Before buying your box I would recommend checking out BoxWorx . Michael custom builds sub boxes for the F series. They are specifically tuned for the truck, where as an off-the-shelf box most surely won't be (not sure how SCS does it). The Pioneers I mentioned earlier, TSSW3001s4 , come recommended along with a couple others. He's been a big help to me in deciding how to go. Just e-mail him if you've got any questions.

Hope some of that helps!

 

I didn't look at the specs for those subs but I agree with Dave if they are that low in sensitivity. You will need a big amp to drive them. Small sealed enclosures require much more power to effectively drive than a larger ported enclosure. Dave already covered that it regardless of enclosure a speaker with a higher sensitivity will be easier to drive.

I do disagree with Dave's other recommendation on amp size. The #1 destroyer of speakers is an under powered amplifier. You want to size your amps with a minimum of %15 greater RMS output than the speakers RMS.

Other than that he is spot on about using a custom enclosure and just running two subs wired for a 2OHM load on a class D sub amp.

 

I looked at JL and Kenwood and they too have 83db sensitivity...

 

So if I went with this amp http://kenwoodusa.com/Car_Entertainment/Amplifiers/KAC-8105D and two if these subs http://www.rockfordfosgate.com/products/product_details.asp?cat_id=4&series_id=31&family_i d=55&item_id=108283&locale=en_US&p_status= and wired them in parallel, would I be good? Am I correct in think that that would be pulling 2ohms off the amp at about 500 watts (going off of your statement about the amp being able to push at least 15% more than the subs). Or should I get the 2ohm subs and wire them in series and pull 4ohms off the amp at about 300 watts?

 

That's what most the pros say, and I used to believe it too, but have come to find out through several installations that it's not the case (as a blanket statement anyway).

For example, the 2 12" Pioneers I've had in my Windstar for the last 11 years can handle 250w RMS but have been powered by a cheapo Legacy 4 channel putting out 180w RMS per channel bridged. The amp and subs are still going strong.

Subscribing to the 15% theory, those subs would have been gone long ago, and you would never be able to power aftermarket speakers with a stock head unit. Yet we all know that's done all the time.

 

Stuck on those Fosgates huh?

You'd have to wire the subs series/parallel, since that amp can't handle a 1 ohm load, and you're now dealing with DVC subs instead of SVC's. You'd have a 4 ohm load at the amp instead of 2.

You can use this to figure out different sub wiring configurations.

 

Series and parallel are two different things aren't they? According to another site someone gave me similar to yours, it said that if you wire in series (hooking the first sub's negative to the next sub's positive and so on) then you add the two sub's resistance, which if I had the 2ohm subs would add to a 4ohm draw off the amp. But if you wire in parallel (positive to positive and negative to negative) then you take the resistance of one of the subs, assuming they're all the same, and divide by the total number of subs. So if I had the 4ohm subs, divided by 2, makes a 2ohm draw off the amp. If that's incorrect then that website said it, not me.

 

Series/parallel are different. Wiring up two of those with "2 OHM" DVC's in a series then the separate subs in parallel configuration would result in a 2 OHM load.

 

So what is the difference between DVC and SVC subs?

 

I should have clarified my statement better. Both subs and full range speakers will run with amps rated well under the RMS of the speaker with no damage. I have done the same with several installations as well.

The %15 recommendation is still a good rule of thumb especially if you like to listen to your music loud otherwise your system will distort fairly quickly once the volume **** gets halfway. The other thing is nowadays amps can be had for dirt cheap. 25 years ago when I got into car audio anything that was decent quality was a mortgage payment.

 

DVC's have "two voice coils" ala DVC vs. "single voice coil". And for the ability to use different wiring configurations of course.

Typically you will use a DVC sub by itself in a small enclosure so you can present a 2 OHM load to the amp to get more power. Most "regular" installations involving just two subs use SVC's and wire them in parallel to a 2 OHM stable amp. That would be the easiest thing for you to do if you want two subs.

 

Ok, so I talked to a guy at work today who is a GURU with this stuff. He looked up some stuff for me and he recommended the Fosgates that I was looking at...the shallow 10" 4ohm DVCs, and then he recommended a 5 channel Polk Audio amp and I believe the model number is PA1100.5. I've also got a set of Kenwood 6x8 components (its the components that have a 6" round speaker with the tweeter built in) on order and he told me to hook the speakers and everything to the amp and don't run anything off the factory radio. I didn't think to ask him today though how I should wire the subs to the amp to get the most efficient setup. I think that amp is not only 2ohm stable, but 1ohm stable as well...
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Nice looking amp, I am assuming since the DVC's are still the choice you are looking to push the amp to a 1 OHM load which would mean wiring the voice coils as a parallel/parallel set up. Is he also recommending you bridge the stereo channels for your Kenwoods up front as well since it's capable?

 

See that's the one thing I haven't figured out the benefit of and when to and not to do it.

And also, what is the advantage to porting a sub? What exactly does that do?