What does "compression" like?

compression is necessary to deliver quiet parts with more volume and loud parts with lower volume accordingly.
the recording always have issues with either low level that is comparable with the noise floor or upper level that goes beyond loudspeaker dynamic range.

Hi Reb.

Compression usually refers to compression of dynamics, where the softest sounds are louder and loudest lower than "normal".

How applied or not is part of how most any recording is made.

Its usually done to make all parts of the recording able to be heard more consistently, especially at lower volumes and/or when external background noise is present..

The negative for audiophiles often comes in as reducing the "jump factor" often associated with good dynamics, and also distorting the presentation of individual acoustic instruments compared to live playing.

The big negative that can come into play with dynamic range compression is when waveform peaks are clipped off as part of the process. This is the most significant and generally offensive kind of distortion often but not always introduced as part of dynamic compression.

Agree with the above posts. A good example of what compression sounds like would be if you listen to a classical FM station on your tuner for a big orchestral piece like a Mahler symphony. At the climaxes where the whole orchestra is playing full blast, you'll notice how the volume drops dramatically. For a contemporary pop recording, as a general rule that won't happen because the recording itself has had its dynamic range compressed, so the difference between loud and soft parts is minimal.