It sounds like a simple question.

If the Genesis has ratios such as 2:1 and 4:1, aren’t those compressor ratios?

And if 20:1 is generally considered limiting, doesn’t that mean Genesis is really a compressor that can simply become a limiter?

The distinction between a compressor and a limiter is actually less binary than those two names make it sound.

What’s the difference between a compressor and a limiter?

At their core, compressors and limiters perform the same basic job: they reduce gain when a signal becomes too loud.

The major difference is how strongly the circuit resists further increases in level once gain reduction begins.

With a 2:1 ratio, approximately 2 dB of additional input level produces 1 dB of additional output level once the signal is in gain reduction.

With a 4:1 ratio, approximately 4 dB of additional input produces 1 dB at the output.

At 20:1, the input has to rise by approximately 20 dB for the output to rise by only 1 dB.

As the ratio increases, the output becomes increasingly reluctant to move any farther.

That’s the territory we normally call limiting.

There isn’t a brick wall between compression and limiting

A compressor and a limiter aren’t two completely unrelated species of audio processor. They’re different operating regions of the same basic idea: automatic gain control.

There isn’t one magical ratio where the electronics suddenly transform from a compressor into a limiter.

Ratios such as 2:1 and 4:1 are normally associated with compression. As the ratio becomes much higher, the circuit increasingly approaches limiting behaviour.

But ratio is only one part of the story.

Attack time, release time, detector behaviour, knee, gain-control element and circuit topology all influence what happens to the signal.

So why do we call Genesis a limiter?

Because Genesis was designed around controlling peaks and constraining level, with a range of ratios that allows that same gain-reduction system to be used more or less aggressively.

Genesis uses a fast FET gain-reduction stage arranged as a feedback dynamics circuit.

The selectable ratio changes how strongly that system responds.

This gives Genesis an important ability:

You can operate a limiter architecture at compressor-like ratios.

At lower settings you can shape dynamics without clamping heavily onto the performance. At higher settings you progressively move the same circuit toward very strong peak control.

What does “feedback limiter” actually mean?

This is where dynamics theory can disappear down a very deep rabbit hole, so we’ll keep it useful.

In a feedback dynamics design, the control circuitry responds to what is happening after gain reduction has been applied.

In simplified form:

Signal rises → output rises → detector sees the result → gain is reduced → output is controlled.

The gain-control system is therefore responding to the result of its own action.

That topology is part of the behaviour and character of the Genesis dynamics section, but the topology and the ratio are still two separate things.

Does a limiter create an absolute hard ceiling?

Not necessarily.

This is another place where modern terminology can create confusion.

Today, many engineers hear the word limiter and immediately think of a digital brick-wall mastering limiter.

That’s a particular kind of limiter.

An analog FET limiter is a different animal.

Real analog circuits have finite attack times. Signals can contain extremely fast transients. Detector circuits take time to respond, and gain-control elements have their own physical behaviour.

So describing an analog limiter as having an absolutely immovable digital-style ceiling isn’t quite accurate.

A better description is:

The circuit strongly resists further increases in output level once limiting occurs.

How much of a transient makes it through depends on the settings and response of the circuit.

And in recording, that behaviour is often exactly what makes analog limiting interesting.

Why give a limiter 2:1 and 4:1 ratios at all?

Because sometimes you want the behaviour of the circuit without maximum control.

During recording, you may want to shave down an unpredictable peak without flattening an entire performance.

Or you may want several decibels of gain reduction while still allowing a vocalist or instrument to retain movement.

Lower ratios make that possible.

Instead of choosing between “compressor off” and “full limiter,” Genesis gives you a continuum between gentle dynamic control and serious limiting.

Ratio isn’t the whole story

Two dynamics processors set to 4:1 can behave completely differently.

Likewise, two limiters set to 20:1 can sound nothing alike.

That’s because the ratio describes only one part of the gain-reduction system.

So, compressor or limiter?

The distinction between a compressor and limiter is useful, but it can make dynamics processing sound more binary than it really is.

Genesis was designed to give you access to the space between them.

You can let a performance breathe.

You can gently rein it in.

You can catch the peaks.

Or you can tell those peaks that the party ends here.

That’s why we call the Genesis dynamics section a limiter.

Not because every ratio is extreme.

Because the circuit gives you control all the way from subtle compression to serious limiting without changing the fundamental gain-reduction architecture.