In composing a photograph it's important to have the point of focus on the subject at hand. A sharp image is what draws the eye to where the photographer wants.
When you are dialing in a stereo system, where's the best point of focus to concentrate on getting right? Voice? Piano? Cymbals and drums? Imaging? Tonal balance?
Of course, the easy answer is we want everything right! But, as well all know, perfection is but an illusion.
Selective focus is actually a benefit, not a hindrance. In photography, it's a method used to draw the eye to the subject. In audio, it's a means of highlighting the system's strengths and reducing weaknesses.
If you're lucky enough to have a reasonably neutral room, your point of focus might be a great overall presentation: nothing standing out, nothing drawing attention to itself. In other rooms, perhaps the best thing to focus on is imaging. Still other systems and rooms might benefit from tonal purity; a perfect holographic center image; deep, subterranean bass; shimmering highs.
No system or photograph can be perfect.
The point of focus helps us appreciate a system's main strengths while minimizing its weaknesses.
