I've been reading a lot about the latest remastering of the Beatles catalog. I keep reading a lot of disussion about "limiting." Is that like compression? I really don't understand either.
Why is it used? What are the ill-affects? What changes? What does it do exactly? etc., etc., etc
Compressors and limiters are really the same side of the coin.
Compressors should be used to keep program within the capabilities of the audio chain. They are misused to increase average levels of pop music to make you sound the loudest on the block.
Basically compressors and limiters should be used to avoid overload of the reproducing chain.
For instance AM radio has a very low dynamic range, FM better but still limited.
The LP medium is about 40 db shy of the full dynamic range of a classical performance. CD can handle all put the largest forces without compression.
SACD does not require compression to fit the envelope.
Compressors have a ratio, threshold, attack and release times. So a 10.1 compressor will compress a 10 db dynamic range to 1 db. So a compressor or limiter has a predetermined signal level where it ceases to be a unity gain amplifier. How quickly it reduces the signal is the attack, how quickly it releases back to being a unity gain amplifier is the release.
A skilled engineer, will set a compressor to keep program within the limits of the medium and playback chain, and set attack and release to be least intrusive to the program.
A limiter is setting a compressor with a high threshold, high ratio, fast attack time and medium to fast release time.
Compressors can also be used (misused) to alter the attack of instruments, especially drum sets. That is another story.
This article, may explain things, but this issue is a broad and complex subject.
