Polk Audio has been around for a long time in the speaker business that says something about the company. The subwoofers are top's also deep bass. Yes i like Polk Audio.
JL audio are a very good line of speakers definitely recommended for any car
Replacement audio speakers for a car can be bought at numerous locations. Good places to purchase them include car audio shops and car dealerships. Replacement speakers can also be purchased direct from manufacturers such as JVC, Pioneer, and Kicker.
Overall I would have to say Polk Audio but this is definitely a personal opinion and also comes with some explanation. For example, I feel that Polk makes better small car audio speakers but I don't particularly like their subs or amps. Polk also makes great home theater speakers and I don't think diamond sells any home theater equipment except freestanding subs. To accurately compare these two brands you would have to limit yourself to a single product and compare that.
It depends on what kind of speaker you want for your car and how much money you are willing to spend. Bose is probably the best speakers you can buy but is expensive. Kenwood and Polk Audio make good subs. If you want a lot of bass these are the best choice.
you need to buy and install an rf adaptor
Many of the best names is car audio are those familiar in other types of electronics, like Polk, Sony and Pioneer. JVC, Kenwood and Alpine also make top quality speakers for cars.
The best car door speakers are Infinity.
This depends if you are going for clarity not loudness brands such as Polk Audio, Infinity and Bose are good choices.
Install a subwoofer, amp, aftermarket speakers, and a head unit. Possibly, the easiest way to get the best out of your car audio system is to upgrade the speakers.
There are several brands of car speakers that offer superior quality: Shallow Mount, MB Quart, Boston Acoustics, CDT Audio, Focal, Alpine, Infinity, Polk, JL Audio, Rockford Fosgate, Kicker, and JBL. To find the best speakers for you, it is recommended that you compare reviews of different specific speaker models. However, any speakers manufactured by the 10 brands listed are sure to offer excellent quality.
there should be a fuse for the audio system in the car fusing panel, but if for the speakers only- then that should be within the audio system itself.
You can if the hookups are the same as your car audio source.