The first type of sound "compression" described is encoding to a lossy audio codec, such as MP3 or AAC. When done correctly, and at a high enough bitrate, this can be transparent (indistinguishable from the original sound in blind listening tests.)
The second type is dynamic range compression, which in my opinion is the worst problem facing the music industry today. In the past 10-15 years, the average LOUDNESS level of CDs has gone up a huge amount. This "loudness race", as it's called, is the result of record companies competing to have the loudest CD in the CD changer, the loudest song on the radio, and the most attention grabbing single.
Unfortunately, for anyone who cares about sonic quality, this extreme dynamic range compression is terrible. It makes music sound unnatural, flat, just plain.. unmusical!
Even Gord isn't immune. Listen to the title track of Waiting For You. The huge dramatic drumbeats that come in are a full 10db louder than the music surrounding them. Now that's impact! The relatively low volume level of the CD as a whole is a sign of a mastering engineer who cares about sound quality, not selling records or getting a "hip", hypercompressed, modern sound.
Compare that to APPT. On this CD, EVERY SECOND of EVERY SONG is at maximum volume! Even the quiet parts of the quiet songs are at the same volume level as the loud drum hits on WFY.
And the really bad news? Going by the tracks I downloaded from iTunes.. Harmony is even more compressed than APPT.. just sad..
to learn more visit
http://www.loudnessrace.net/