Will running 2 ohm with 4 ohm dual voice coil sub woofers in parallel cause problems to the speakers or sound quality?

Answer 1

The purpose of dual voice coils is to offer more wiring options.

To answer your question we would also need to know how many woofers, and therefore how many voice coils, are involved in this equasion.

For wiring guides, check http://www.rockfordfosgate.com/rftech/woofer_wizard.asp.

As long as you don't wire at a lower ohm load than your amp can handle [ex. wiring to 1 ohm when your amp is only 2 ohms stable] or wire for more power than your woofers can handle, or allow for too much distortion to be played through the woofer, there should be no damage to your equipment. Distortion will damage your woofer before overpowering will.

Ohms are a measurement of resistance to electricity and so the higher the ohm load, the lower the power. If you wire an amp to play speakers at 4 ohms, the speakers will receive less power than if they were being played by the same amp at 2 ohms. Off the top of my head, the Kenwood KAC-9103d pushes 500 watts rms at 4 ohms and 900 watts rms at 2 ohms. The trade off is that while the lower ohm loads offer more power, they come with more distortion as well.

Have fun.