Okay everybody, sit down. Class has started. Getting into car audio can be the most intimidating thing to start. So many brands, power ratings, trying to find a compatible amp. On top of that, a lot of companies lie about there power ratings. Ok so lets start with subwoofers. When looking on amazon you will see a lot of subwoofers claiming RMS and max power. RMS is the rated watts that a subwoofer can handle. Max power rating is just a fake number companies will make to make there product sound better than it is. ( Heres an example Pyle PLPW10D 10-Inch 1000 Watt Dual 4 Ohm Subwoofer https://www.amazon.com/dp/B007JV7CRC/ref=cm_sw_r_cp_api_nixzybQY8YTXY ) notice how 1000 watts is in the title. If you put 1000 watts rms on that sub it wont last one min. Its rms rating says 500 watts rms. Now that subwoofer linked above is a pyle of crap. Stay away from these brands (Pyle, Planet Audio, Boss not to be confused with Bose) these are better choices ( Rockford, Pioneer, Kicker, Alpine) balls to the walls best choice ( Skar Audio, Sundown Audio) there are tons of brands but those are most common. A good rule of thumb is looking at the size of the magnet. The bigger the magnet the more power it can handle and usually better quality. (Example https://www.amazon.com/dp/B00EVZDW00/ref=cm_sw_r_cp_api_DvxzybSARDNC5 ) long story short is you get what you pay for. 30$ 500 watt sub looks to good to be true because it is. Build quality is junk and its going to sound like crap. Now if you want a good thump. I recommend staying in the 300-500 watts rms range. It wont kill the budget and you can get some decent bass. Anything higher than that, you will start to get into the car rattling range. Now back to subwoofer specs, you will see different types of ohms and voice coil configurations on subwoofers. Ohms is resistance. Lower the ohm=easier power flow, so more power can be delivered easier. Now voice coil config can get confusing. There can be one of two options on a subwoofer, single voice coil And dual voice coil. A SVC is simply one positive and one negative terminal on a subwoofer. When you have a DVC you have two positive and two negative terminals. Now the reasoning for this is with a DVC sub you can change the ohm rating on the sub itself with different wiring configurations. You can change a dual 2 ohm subwoofer to 1 ohm wiring in parallel ( http://images.crutchfieldonline.com/ca/learningcenter/car/subwoofer_wiring/1-DVC-2-ohm-mono-low-imp.jpg ) thats one example, you can raise, lower or keep it at original ohm. See with a single voice coil sub, you cant change the ohms because there are only one set of positive and negative terminals BUT you can use an identical sub and use its set of terminals to change the ohms of both subs ( http://images.crutchfieldonline.com/ca/learningcenter/car/subwoofer_wiring/2-SVC-2-ohm-mono-low-imp.jpg ) now the whole reasoning for this is because at different ohm ratings, you will get a different output on your amp. (Remember lower ohm= higher power) so heres an example ( i'm making these numbers up btw) a amp could have these listed... 8 ohm 50 watts, 4ohm 100 watts , 2ohm 200 watts, 1ohm 400 watts. Now lets say you have a dual 4 ohm 200 watt sub. You would want to wire it in parallel to change the ohms to 2 and then you will get 200 watts, which is what my fake sub was rated for. Now if you have the same sub but was a single voice coil, that wouldn't be the best amp for that sub. It would only receive 100 watts when its rated for 200. So it would be recommended to find a more compatible amp. I shouldn't have to say this but you obviously want to match watts rms with your subwoofer and amp. They say to stay in 80% - 125% of rated power of the sub. So that pretty much means if your sub is 350 watts, and you have the ohm configed to deliver 400 watts then thats fine. If its a good brand and has good build quality you can push it farther than its rated for. Like sundown audio subwoofer can be pushed 300 watts more than rated and run perfectly fine. You will know when your pushing your sub two hard. It will either make a clunk meaning it bottomed out. (It moved in or out to far) or you will smell something burning. Thats your voice coil starting to heat up. If that was to happen, turn down the bass and let it cool and adjust bass level. Now lets talk about good amplifiers, there probably going to be the most expensive item in car audio. Rule of thumb for amps is to not be cheap and don't fall for all the eye candy. The bigger and heavier the amp, the more believable the power rating is. https://www.amazon.com/dp/B00011KLXE/ref=cm_sw_r_cp_api_eIyzybKGRQYJV ) something that small is no way going to output "3000" watts, you probably wouldn't get more than 500 watts. Alot of cheapo brands will put lights and crazy colors to try and attract you to there products. Thats usually a sign of junk. Make sure you look at rms power and reviews will usually say if it was a good buy. Companies like boss will even lie about rms. Now subwoofer amps are called class D amplifiers. There usually two channel or mono block meaning how many terminals there will be on the amp. You can use a multi channel amp on one sub if its strong enough. Also if your planning on wiring your sub to one ohm, make sure the amp is stable to run at one ohm. There is also bridging. When you take one positive of one channel and one negative of the other channel of the amp. So it combines the power of both channels. Amp needs to be compatible to do that. I recommend getting an amp with a bass knob but any decent brand should have one included. A good method of finding true rms of an amp is adding up fuse ratting and multiplying it by voltage. So my amp claims 1500 watts. It has no fuse but has an inline fuse by the battery ratted for 100 amps 100x12=1200 watts. 12 being average voltage, that number can fluctuate to 13.5. My amp is actually compatible up to 16 volts. 100x16=1600 watts, Most amps being only 80-90% efficient = 1500 watts. Also get a decent amp kit, if you get cheap junk, you can choke your amp. If the cables going from the battery to the amp are two small your amp can short out. And for the box, build one. Many sub manufacturers will have a recommendation for there sub, and have all the dimensions listed. If thats not your thing then you can buy one but they can be expensive. I recommend a ported box over sealed. I think thats about everything....if you have any questions, i'm here to help. Don't get discouraged, if you take the time to do it right, your 400 watts system will sound better than your buddies 3000 watt system.

I forgot to mention this but its better to over power then to under power your subwoofer. If your amp is 300 watts and your sub wants 500 then your going to have a number of problems. Your amp will produce alot of distortion and it will be under alot of stress. It will also get hot enough to cook on. Not only that but it will also damage your sub. Think about like this, your sub if built to move farther than the amp is capable of pushing it. This causes clipping and you will get loud popping sounds from your sub.

Also "professional" installers may not be the most trustworthy guys out there. Not saying there all bad but if you show them that you don't know much, they may try to sell you the junk i told you to stay away from at a premium price. The installation really isn't that difficult. Do a some research and it will only take a few hours at most