When a system plays at all levels without ever drawing attention to itself we might say it was without noticeable effort.
Years ago when I was deep in design that was perhaps one of the more elusive goals for a power amplifier.
Time and again my designs would sound right until the music got loud.
The louder it got the more I became aware of its struggle to get there. It took obvious effort.
Bigger, higher-wattage amplifier designs seemed to reduce that effort but, surprisingly, lowering feedback, and linearizing circuits through the use of active current sources had the biggest impacts.
It took a great deal of time and effort to get there but, over time, the designs hit their mark.
Paul McGowan / PS AUDIO