?We are talking about how a 2,000 watt amplifier can handle a spike of 123dB. Well, a spike is like a transient like a kick drum or snare drum hit. What if we could compress or limit the entire mix to smash down those spikes and then bring up everything else? With hard limiting, we can ensure that we never have out of control spikes jumping out of nowhere. By doing this, we don't need nearly as much power because we've reduced our need for headroom. However, our system will sound much louder because all the RMS stuff (constant signal like a guitar or bass) can be cranked louder. (It's important to note that one or two loud spikes that are limited probably won't even be noticed, but will allow you to be much louder with less power!)

This is the same basic concept used to master modern cds. All cds have a limit of 0. (They use negative numbers with digital for some reason). So if your cd sounds too quiet, it's probably because you've got a few peaks that are forcing all the other signals down. A limiter or compressor is generally used to correct this (although most of the magic is in the mix itself...but that's 1,000 other articles).