Finding a compatible sub and amp can be a hard process. It is important to look at several variables. An easy way to tell if a sub and amp are compatible is by visiting the Sonic Electronix website. This site provides a free amplifier and subwoofer matching tool.
any radio can have a sub you just need a amp to power it.
You could have an amp that has insufficient watts so take it to a place like bestbuy to see if your amp or sub has blown. If its your amp you just have to get a new one but if it's your sub then you have to get a new sub it is easier to replace an amp but both are pricey
You can connect a sub and speakers to one amp, depending on how many channels your amp has. A 4 channel amp will be able to run one (or two) subs using two channels (one bridged* sub or two subs) and two speakers running one channel each. A 2 channel amp will run 2 speakers or one bridged sub. A 6 channel amp will run one bridged sub (or two subs), 2 front speakers and 2 rear speakers. In my opinion, you will get the most performance, depending on which amps you use, by using a monoblock amp for your sub and an amp with enough channels to run all of your speakers. # Bridged = putting together the power of two channels to run one sub or speaker. Note: not all amps are bridgeable.
yes the amp is in the firewall behind the radio and also yes you can replace the factory sub with any 8 in sub of your choice.
Yes
you just need one, a general rule of thumb is that the wattage on your amp should be double the wattegae on your sub, hence if you have a 1200 watt sub you'll need a 2400 watt amp
If you amp is bridgeable you run + sub wire to ch 1 + then the -sub wire to the - of ch 2 of the amp. The same with the other sub + ch3 - ch4 that's how to bridge your amp.
That's where u bridge the amp to combine both channels power into one sub.
You connect speakers and a sub to an amp by placing each wire into the appropriate connector. The connectors on the side of the amp are labelled for front, back, side, and sub depending on the configuration.
It will say mono if its only 1 channel which is a sub amp only.
Depends if you are building heavy bass system with quite a few subs then a mono amp would be suggested but if it is just a single sub just for a standard bass upgrade then a 2 channel amp would be fine you can still use a mono amp on one sub just remember to take into perspective the RMS rating and the Impedance on both the Subs and the Amp
You bridge the amp not the sub.