Enhanced and widescreen sound

As far as the PAL countries are concerned, the FM sound carrier power was often reduced relative to vision power as the sound circuitry of the receiver increased in sophistication. The attainable picture quality could then improve, but when experimental sound enhancements, such as subcarrier stereo were introduced, the quality of the sound was not as good as expected. In addition, pictures as well as sound could deteriorate in older receivers. A major problem of any sound enhancement continues to be the backward compatibility with existing receivers