Although picture quality (improve) greatly with the development of flat-screen televisions, sound has taken a dive. The problem is that televisions with slimmed-down screens have insufficient room for decent speakers to be fitted to them, either at the back in the frame (框). Such televisions are usually connected to external sound system, such as a sound bar or a home-cinema system, (make) their audio quality better.
The loudspeakers of early televisions were as big as the screen, but engineers have got good at making speakers smaller and putting them into (tight) spaces. Sony is the first company to develop it calls Acoustic Surface.
Unlike (tradition) ones, this screen gives off the light directly. This means it is able to vibrate (振动) more (flexible). This vibration is invisible to the viewer and does not affect picture quality. One beneficial consequence is that a program's music (broadcast) directly at the viewer instead of from the side. It is also possible to create stereo (立体的) effects by (move) the sound's point of origin across the screen.
