Great amp for subwoofer.
Okay, so I am not a "pro" audio installer it is just a hobby that allows me to putter around, play with solder and copper wire, and hurt my ears. With that said, I am on a pretty tight budget so even the "cheap" components put a dent in my wallet, forcing me to make my purchases over time. I am going to post this review under each of the components listed below, so here is what I have built for my old SUV as of 3/1/16:
Head Unit: http://www.amazon.com/BOSS-625UAB-Single-DIN-MECH-LESS-Detachable/dp/B00B65J5B8/ref=sr_1_1?ie=UTF8&qid=1457824650&sr=8-1&keywords=boss+625uab
This little unit was received as a gift, but purchased on Amazon. I selected it based on bluetooth connectivity and DIN size. Radio reception is pretty typical. Playback from USB and SD is clunky but acceptable. Bluetooth connectivity for phone calls has a thin, tinny sound at the other end, but of course it sounds really good in the passenger cabin when it comes through all of the speakers. I actually have a philosophical objection to phone calls in a vehicle, so I don't use it. It shines for me as a bluetooth receiver for my media player; no noise or distortion, instant connection once paired, and reliable while connected. I haven't had a bluetooth battle royale to see if a passenger's device will disconnect mine, but maybe someday in the future I will find out for certain. The EQ presets are pretty darned limited, but if you do what I did and pair it with an external equalizer, then everything will be fine for you. It is a very acceptable substitute for the stock Ford radio, so buy with confidence.
This was a bit of a spur-of-the-moment purchase that worked out remarkably well for my system design. It is a powered EQ, so it will boost the signal from your head unit to whatever amplifiers you choose to use. It has four speaker channel outputs (2 RCAs), and one subwoofer output (1 RCA). It has 2 RCA inputs (CD and AUX), and a front panel input for mp3 players/iPods. There is a fader adjustment, 2 separate level controls (one for total level and one for subwoofer), a crossover for the sub (40Hz to 400Hz), in addition to the sub, low, mid and high adjustments. I have not maxed out the unit's level control with my system, but from low to about 3/4 setting provides a substantial change in overall volume. The unit is extrememly solid and durable. The only drawback is that if you are like me and you change music genres frequently, you will fall victim to the eternal joy of constantly fiddling with the dials to get that "perfect" sound for whatever you are currently listening to. Definitely purchase with confidence in the quality you'll receive.
First amplifier (door speakers): http://www.amazon.com/Planet-Audio-AC800-4-800-watts-Amplifier/dp/B00HG6W1VM/ref=sr_1_1?ie=UTF8&qid=1457824825&sr=8-1&keywords=planet+audio+ac800.4
This four channel amp has done exactly what I wanted it for; to power my door speakers. I wanted a good, balanced sound in my vehicle, and in combination with the other components listed here, I acheived something that makes me happy. YMMV. This amplifier provides plenty of juice to the door speakers (also Planet Audio) with enough bells and whistles to make the system sound like someone much more talented than me installed it. This amp doesn't introduce any noise or distortion and it powers my door speakers to volumes that are downright painful, without clipping. It looks very sharp, fits beneath my passenger seat without overheating into protection mode, and gives me way more than enough power for my uses. The only issue that I had was that the holes for mounting were too narrow for the 1/4" driver I was using to drive the self-tapping hex bolts into my floorboards. Also, I would mount it on spacers of some sort, since the cooling vents are located on the bottom-side of the amp. This has been a fantastic purchase for someone like me, with realistic expectations. This is not going to even get you placed in an audio competition, but you won't have any problems hearing your tunes while taking that road trip.
4 door speakers: http://www.amazon.com/Planet-Audio-TQ623-6-5-Inch-Injection/dp/B003GSLE6W/ref=sr_1_2?s=car&ie=UTF8&qid=1457824210&sr=1-2&keywords=planet+audio+speakers
My initial review was a 4 out of 5 stars; I have to revise that to a 5 of 5. My head unit alone did not provide enough power to drive the speakers properly, but in conjunction with the amplifier and equalizer I have listed above, I couldn't be happier. The highs are crisp and clear, the mids are chunky, and the lows are good. I have not yet been able to drive them to clipping, and thanks to my poor hearing I DO crank the volume more than most. These do not compete with Kenwoods, Rockford-Fosgate, or any of the pantheon of quality speakers available; they do beat the absolute daylights out of anything that you will ever be able to find for under $20. Power them with an amp, and enjoy a great sound that won't break the bank but might bruise your eardrums.
Second amplifier (subwoofer): http://www.amazon.com/Planet-Audio-AC1500-1M-1500-watts-Monoblock/dp/B003GSLE2Q/ref=sr_1_1?ie=UTF8&qid=1457824886&sr=8-1&keywords=planet+audio+ac1500.1m+anarchy
This is the third Planet Audio component that I have installed, and it works just as well as the previous two components. I am not powering a huge sub setup, just a single 12" DVC (named below) in a ported enclosure and wired to 2ohms; it booms enough for my grumpy old ears and provides a full sound for the music that I love listening to. With all of my components set to 1/2 gain, my setup rattles the frame, trim panels and rearview mirror on my vehicle. That is not suitable for most of the music that I listen to, so I am thankful that this amp comes with a remote level control, and unlike other reviewers, I know that it works properly. I have not driven the sub to the max yet, as I am still working through the break-in period, but I have had it turned up plenty loud enough for my needs and then some. This amp will give you great, noise-free power for any budget build.
Subwoofer: DS 18 12" 4ohm DVC with vented enclosure. (my specific model is not listed on Amazon, but I am very pleasantly surprised by the sound and power handling.)
So that is the breakdown of the several components that I have used to complete my car audio system. I'm not a "pro" and I'm not going to win any competitions, but I don't have any plans to do so either. I am able to listen to my music loud, with great power and clarity, and it comes on every single time. You CAN build a decent sounding system without breaking the bank. Planet Audio products have more than a few negative reviews, but I would definitely buy their products again. All products will eventually have that one dud that makes it through QC; thankfully I did not receive any of those duds. You also have to balance your needs vs. your expectations; if you absolutely must conform to brand-name recognition, feel free to throw your money around. But you can do the math on your own based off this list, and you won't find much better bang for your buck.