sentences:  Musician Neil Young is a harsh critic of the sound of the original CD format, but has expressed approval for the sound of higher definition formats such as SACD, which he believes has a greater safety margin between its ideal behavior and the theoretical limits of human hearing.However, many independent listening tests and mathematical studies have shown that Young's assertions are basically untrue.Regardless, in 2011, Neil Young filed paperwork to trademark his own developing high-resolution audio player.