"Disappearing in-walls" is the concept behind a new Def Tech architectural speaker line. These in-walls install without much fuss or spackling. Small diameters, hidden flanges, and low-profile micro-perf grilles make them nearly invisible. Pivoting aluminum tweeters make them versatile. Woofers range in size from 3.5 to 6.5 inch and pricing starts at $179 per speaker.