Sound: play open strings alone; play slow scales, sustaining a 20- to 30-second bow; practice everything in the lower or upper half; or watch your contact point in the mirror.
Audiovisual records -film, video, radio and recorded sound material -mirror human creativity and the living fabric of our cultures.
音像制品—电影、录像、广播、录音材料—折射出人类的创造力，是活的人类文化织体。
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Mirror lock-up (MLU) is a feature available in some SLR cameras which aims to minimize camera shake induced by mirror-slap (which produces the characteristic snapping sound of SLR cameras).