Occasionally I see people confused by all the different kinds of limiters. Words like ‘brickwall’ and ‘Maximiser’ can confusing – especially when marketing material is heavy on hyperbole and light on substance.
It’s quite simple really.
A limiter is – at its essence – a compressor with a very high ratio and a very fast attack. While their technical design is similar (reducing the gain when the signal rises above the threshold level), their intended use is somewhat different. Compressors are generally used to reduce audible dynamic range – the difference between loud sounds and quiet sounds. Limiters, on the other hand, and designed to transparently reduce peaks. When a limiter is correctly used, it should not audibly change the sound (including the dynamics of the sound). Limiters are purpose-designed compressors that are specially tuned to transparently reducing peaks.
By reducing the peak level without changing the sound, limiters are ideal for reducing the headroom required by the audio. Limiters allow a hotter signal to be recorded with a lower relative noise level (signal-to-noise ratio).
Brickwall limiters are a specific kind of limiter that is designed to prevent digital clipping (signal going over 0dBFS). They usually have instant attack and infinite ratio.
Clipping is a process sometimes used in mixing and mastering in place of limiting. Instead of reducing the gain of the peaks, the peaks are clipped (cut off or distorted). As you can imagine, it’s a much more extreme approach than limiting. I’ve written more about clipping and limiting here:
The term ‘maximiser’ doesn’t have a specific meaning. It’s most often used as a marketing term to refer to a brickwall limiter that incorporates a blend of clipping to make the signal very loud. Sometimes maximisers also employ other processes such as tonal adjustment (such as ‘bass maximisers’), phase shifting or exciting (‘sonic maximisers’), analogue modelling (‘tube maximisers’), etc.
Don’t assume that the marketing material is a literal description of what goes on under the hood. Not to say that manufacturers lie, but sometimes the people who write the marketing material aren’t the people who design the algorithms.