Reddit reviews KnuKonceptz Kolossus Flex 0 Gauge OFC Power Amp Wiring Kit

The price difference is mostly quality and sometimes name. Also some are underrated so while it looks like they can handle about the same some can be pushed to double without issue. If all you want is loud the square 15 inch L7 is a really good sub since the cone design gives it more area (15x15=225 in^2 ) compared to a even a 15 inch round sub (3.14(7.5)^2 =176 in^2 ). That's 22% more cone. The only problem is they are harder to find from reputable dealers since it is a few years old. If you deal with CL or ebay there are plenty of used or even new stock out there.

Watts=Volts X Amps

Your alt should be charging at 14.4 but once you go under load it will drop so not great to use that for calculations. I used 12.5 to be on the safe side as if you build it to match you'll rarely get that low. If you're running a 270 amp alt you'll want to leave a good chunk of that for the rest of the car. Most people say 100 amps but every car is different. If you're running a second battery you'll be fine with leaving 70amps. Also keep in mind HD alternators aren't putting out 270amps at idle so if you're sitting at the light you'll mainly be pulling from your batteries. I'm sure whoever you buy from will give you some idea on how much output it has based on RPM. So basically

270 amp alt
-70 for "car stuff"
xWatts =12.5V X 200A

Solve for x we get 2500. That's a safe wattage to push. You can go as high as 3500W on the same setup (3500W=14V X 250A) but you can see that only leaves 20 amps to run the rest of your car (unrealistic) and assumes voltage will stay over 14v (also unrealistic). So while it will work you're on borrowed time. I'm a huge alpine fan. My old single type r @500 watts in a ported box (1.7 ft^3) would shame most 2 sub setups running at "twice" the wattage. 1k is enough to rattle the wipers off the windshield (my 500watt setup can do this). At 1500-1600 you're flexing the roof. 2k+ is an absurd amount of wattage.

The resistance thing you more or less have to match. Most amps are 1ohm or 2 ohm stable. You can always push higher in fact a subs resistance will increase as it's in use due to heat and air resistance when moving the cone (google impedance rise for more info). The only draw back to pushing it higher resistance means you're losing output. Take this RF amp for example it's rated at 1200w @1 ohm but it's rated at 400w @4 ohms and 800w @2 ohms. Now the amp is drawing the same amount of energy from your electrical system for all of those outputs but your output is all being lost to resistance. Alpine's amps are mostly 2 ohm stable. Most class d amp makers can do 1ohm stable. .5 stable amps are virtually unheard of. 99% of .5ohm setups are 1ohm stable amps being pushed to their breaking point. Guaranteed to void warranty (although not sure how they would prove you ran it at .5). Most people running them are banking on the impedance rise I mentioned earlier but it's hard to calculate how much impedance rise you can consistently achieve so many of these systems go up in smoke. Amps will tell you if they are 1 or 2 ohm stable. Most subs come in dual 2 or dual 4 setups so you can get to 1/2 ohms with whatever sub you chose. I'd stick to 1 or 2 ohm setup until you're ready to fry some equipment.

Here is how I would do it.

High cap alt= ??? 300
Battery = ??? 300-400
SoundQubed HDS315 (dual 4 ohm) 2 = $340
Alpine MRX-M110 *2 = $508 (if you can find a MRX-M240 you can run a single amp but you'll need to switch those subs to 2ohm which isn't an issue)
0 AWG going to your second battery -115 Note you can run 4AWG from the sec battery to the amps.

10 ft^3 box. Will more than likely need to be custom made. = ~150 for materials/carpeting

You're looking at 1700 on the low end. If you already have the alt or batteries just subtract what you already have and you'll have a good idea of what you need. If you scavenge CL you can find a better system for the money as most people sell their systems at a loss. Depends if you're willing to risk buying used.

suggest subs x 2 - amp - step up to wire


Same price, takes up more space.

Two nice 25 mm xmax 15's on 2k for $500. Crazy.