720p This HDTV format has 720 scan lines and uses progressive scanning. The 720p format is best for fast-moving motion scenes.
1080i This HDTV format has 1080 scan lines and uses an interlaced scanning system. The 1080i format has a sharper image than the 720p format.
1080p This HDTV format has 1080 scan lines and uses a progressive scanning system. It is often referred to as full HD.
Acoustics Higher-frequency sound waves travel in straight paths and are easily deflected and reflected by hard surfaces. They are also easily absorbed by porous fibrous materials. Lower-frequency sound waves (below 100 Hz) spread widely, so they are not impeded by obstacles and are less readily absorbed. As sound waves meet nearby materials, they are selectively ...