Table 1 Scale of signal distortion, background intrusiveness and overall quality

5- very natural, no degradation

5- not noticeable

5- excellent

4- fairly natural, little degradation

4- somewhat noticeable

4- good

3- somewhat natural, somewhat degraded

3- noticeable but not intrusive

3- fair

2- fairly unnatural, fairly degraded

2- fairly conspicuous, somewhat intrusive

2- poor

1- very unnatural, very degraded

1- very conspicuous, very intrusive

1- bad