Amplifier gain compression...?

[Captainobvious]

I came across this article and wondered if there's any merit here. Is gain compression an issue in car audio amplifiers? If so, do the manufacturers input voltage ratings correspond with the point of compression or simply a point of "X" distortion? I've never considered this (nor heard it mentioned) so this is new territory for me.

http://na.tm.agilent.com/pna/help/We.../Gain_Comp.htm

Here are a few quotes from the article:

"What Is Gain Compression? Gain compression occurs when the input power of an amplifier is increased to a level that reduces the gain of the amplifier and causes a nonlinear increase in output power."

• The amplifier has a linear region of operation where gain is constant and independent of power level. The gain in this region is commonly referred to as "small-signal gain."
• As the input power increases, the amplifier gain appears to decrease, and the amplifier goes into compression.
• The most common measurement of amplifier compression is the 1-dB compression point. This is defined as the input power (or sometimes the output power) which results in a 1-dB decrease in amplifier gain (relative to the amplifier's small-signal gain)."
  
  

[PaulD]

I thought this was what the gain knobs were for ... to match the output of preceding device with the input of the amp