Infinity Pr6512Is Primus 6.5 Inch 2-Way Multi-Element Speakers New Primus speakers feature our patented Plus One polypropylene woofers which feature more radiating cone area for increased output and edge-driven tweeters for better high frequency dispersion. Speakers are super clear at the top with vocals, horns and strings and deliver big bass with plenty of slam. Long story short: superior sound top to bottom. True 4 ohm architecture gives the amplifier room to reach peak power for increased depth and detail. In addition to passing demanding reliability and environmental testing, all speakers are individually voiced by some of the world's best transducer engineers to authenticate the Infinity sound. It's not a coincidence that Infinity is one of the world's top-selling car audio speaker brands. Patented Plus One Polypropylene Woofers - Polypropylene cones with up to 35% more radiating cone area than other cones in the same class provide higher sensitivity, increased low frequency output and better tonal balance. Edge-Driven Tweeters - Edge-driven tweeters deliver wider dispersion and smoother high frequency response with increased power handling for high- and mid-frequencies. True 4 Ohm Architecture - True 4 ohm architecture with low impedance voice coils give the amplifier room to deliver peak power providing stronger and clearer sound with better depth and detail. Infinity speakers have to undergo a testing process that would destroy lesser speakers. Infinity freezes them, bakes them, shakes them, blasts them with ultraviolet light and drives them at full power for days at a time. Voicing of Speakers - Speakers are individually voiced to assure high quality audio versus ?off-the-shelf? manufactured sound. This means that specifications as well as speaker characteristics are considered when tuning the Infinity sound.