I have just the standard speakers in my Nissan. I have installed a sub-woofer and an amp and that works fine.I have heard about 6x9 speakers and 4 speakers - if I get some, will I need another amp or anything, or can they just replace the current standard ones?Thanks!
If you have 4 and 6x9 speakers in a Nissan I'm guessing that there is a Bose factory system in there. If you are still using the factory radio and amplifiers it is not a good idea to just replace the speakers if it is Bose because the factory speakers run at a real low ohm load (usually 1.5 or 2 ohms). If it is a standard Nissan stereo you should have 6.5 speakers all the way around, depending on the model of car. If this is the case you can replace just the speakers with no problem. The major benefit to adding an amp to interior speakers is that you have a lot more flexibility as to how you want the speakers to sound.
Dec 7, 2017