Subwoofer help needed.?
Sub impedance is about matching up with a particular amp. One s not "better" than the other because it s 4 or 8 ohm. However, 8 ohm subs are not often used in car audio because most amps, especially subwoofer specific amps are built to operate at low impedance -- typically 1 or 2 ohms. A pair of single voice coil 8 ohm subs can be wired parallel for a total of 4 ohms. A pair of single 4 ohm voice coil subs can be wired for 2 ohms. Subwoofer brands to avoid -- Crunch would be pretty high on the list. I have no idea what model Crunch you have, but I can guarantee you it s not a 1300w sub -- that would be a peak/max rating with the actual rms power handling being a fraction as much. Besides, having a sub capable of handling a lot of power isn t helpful if you can t afford a powerful amp to run it. There s a lot more to say about sub/amp matching but at this point your question can t be clearly answered w/o knowing what amp you ll be using.
4 ohm is better when bridged into mono, 8 ohm is better when running low pass filter stereo drivers. You have to think about this beforehand, hap hazard only ends up more expensive in the end run of life. If two sub 4 ohm driver coils not bridged mono, hook the coils in series to a get a balanced 8 ohm load. Amplifiers are very particular about the loading impedance, you must match the load or it no work right. Many make the mistake of hooking the amp bridge up wrong, thus dumping a 2 ohm load on a 4 ohm. This happens because they don't understand the difference between series and parallel electrical load.