We hadn't really expected Griffin to release a sequel to its 2008 iPhone passive sound amplifier AirCurve, but here it is: AirCurve Play ($20) has been redesigned for the iPhone 4, preserving its predecessor's clear hard plastic waveguide design, changing the position of the iPhone from "docked" to "relaxing inside," and adding both a rubber sleeve to protect the iPhone's body, then a flip-out metal stand to keep everything upright. Capable of increasing…
