As Guitarhacker pointed out, normalization is limited by the maximum volume of the recording. Normalization works by going raising the volume of the whole sound - but only so that none of the sound exceeds the maximum.

That means that if any of the recording is already near the maximum (typically one of those "spikes", or "transients" - often a drum beat), there's not much room to raise the volume.

A compressor works by raising the raising the volume where it's low ("low level compression"), and lowering the volume where it's high ("peak limiting"). You lose variety in volume, but generally gain in overall loudness. You'll need to know how to fiddle with settings to get the best results, or find VST with presets or simplified settings (like floyd jane pointed out).

The "transparency" of the compressor is determined by how fast it turns changes the volume, and how quickly it returns to the normal settings. Typically, you don't want to hear the knob being turned (so to speak), although sometimes that effect (called "pumping") is desirable.

A master limiter is just a more specialized compressor. It's named as such because it's typically placed on the master buss to limit the signal so it doesn't exceed the maximum volume ("peak limiter"). But you might find it an easy way to increase the volume.

There are a number of free VSTs that specialize in making a mix louder, such as this. They're typically just compressors with the settings simplified so they're easier to use.

Last edited by dcuny; 02/10/16 06:03 AM.
-- David Cuny
My virtual singer development blog

Vocal control, you say. Never heard of it. Is that some kind of ProTools thing?