Plus One® woofer cones - This patent pending technology deliver a cone with more surface area than competing models of the same size. The result is increased bass output and higher efficiency. Infinity Reference speakers have two-ohm voice coils. This unique approach extracts more power from your amp or head unit. Many factory OE systems include two-ohm speakers. Infinity Reference speakers are perfect for those applications.If your head unit or amplifier is rated to drive a four-ohm load, Infinity Reference speakers are still the best option. Edge-driven textile dome tweeters - These are not commonly used w-domes, but fully-edge-driven domes like those found in better home audio speakers. The benefit is increased power handling and reduced distortion at high output levels. This technology also allows for better integration with the mid/woofer. Each Infinity Reference component system includes a pair of laboratory optimized passive crossover netorks that include tweeter adjustment. If the tweeters are located low in the doors or if you are looking for a brighter sound, set the tweeter at +3dB. To facilitate proper installation and location of the tweeter, each Reference component system includes Infinity's patented I-Mount™ (patent no. 5,859,917) tweeter mounting kit including the Starfish™ OEM adapter.