Dynamic Processing: Using The Dyn3 Expander/ Gate

By now you are probably familiar with the plug-in library that comes with Pro Tools and you have probably noticed that there are several plugins from the Dyn3 series and the Expander/ Gate is one of them. In the same series you can also find a compressor and a de-esser.

This batch of plug-ins is designed to take care of almost any dynamic processing task you might need to fulfill while mixing. What I love most about the Dyn3 series is how easy it is to work with the plug-ins and how friendly the interface of every plug-in is – not to mention that they all sound very decent.

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What Is An Expander/ Gate?

Before diving in and looking at the parameters of the Dyn3 Expander/ Gate let’s take a moment to understand what a gate and an expander are and what’s the difference between the two. Both are iterations of the same processing process and they basically function the opposite from how a compressor functions. Basically, an expander reduces the amplitude of a signal that falls below a set threshold.

For example, if you have a bass track with an expander inserted on it and the threshold is set at -15 dB, every part of the signal’s amplitude that’s below -15 dB will be reduced by a certain amount of dB and the speed of the reduction is controlled by a ratio. A gate does the same thing but with a very high ratio, thus effectively muting everything that’s below the threshold.

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When To Use An Expander/ Gate

Let’s look at some scenarios where an expander/gate might be very useful. Imagine a multi-track drum recording: every microphone recorded the drum it was placed near to but also bleed from all the other elements of the kit. How can we process the kick track, for example, in order to get rid of bleed?

Using The Unit As A Gate

Most effectively, this can be achieved with a gate. By using a gate you can set the threshold in such a way that only the kick – which will have a much greater amplitude than the bleed from the rest of the set – will “open” the gate (exceed the threshold).

Let’s imagine another scenario.

 

Using The Unit As A Downward Expander

You just came up with an awesome guitar riff and you hook up a mic and record the riff to Pro Tools. When you listen back, suddenly you realize that the buzz from the amp is very apparent between chords and in the parts where the guitar riff is more subtle.

By using an expander you can control this and effectively eliminate the buzz by finding the amplitude at which the buzz becomes too loud and setting that value as the
threshold of the expander and then playing with the ratio until you are happy with how fast the “tails” will drop in volume. There’s countless applications for an expander or a gate and I am sure that after you get comfortable using it in Pro Tools you will come across loads of situations where you will find it very, very handy.

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The Controls Of The Dyn3 Expander/ Gate

The Dyn3 Expander/ Gate in Pro Tools is quite straight forward and simple to use. Let’s take a look at the parameters:

The Lower Section

The threshold, the most important control on the unit is the first on the bottom right, colored in orange. As mentioned above, the threshold parameter controls the amplitude level below which signals will be processed by the unit. When the signal falls below the threshold, the release time determines how long it takes for the unit to start reducing the gain of the signal.

The ratio affects how the gain reduction is applied to the signal when it’s below the threshold. For a simple gate ratio should be 100:1. For expansion use a gentle ratio like 2:1 for starters. The range sets just how much gain reduction is applied below threshold. When the signal goes over the threshold, the attack determines how quickly the unit will stop reducing the gain. Hold is the time the gate will remain “open” (will not apply any gain reduction) even if the signal falls below the threshold.

The Upper Section

The look ahead button enables the unit to analyze the signal ahead of playback thus being able to react quicker and more correct to amplitude changes and fast transients. The HF and LF are high-pass and a low-pass filters that enable the user to filter the incoming signal. You can also side-chain the unit in order to make track “duck”. This is easy to set-up:

Sidechaining

Let’s imagine two mono audio tracks: a vocal track and a guitar track. Insert the Dyn3 Expander/ Gate on the guitar track. You can instantiate a send from the vocal track and after pressing the little key button above the filtering section head over above the meters and choose from the drop down bus list the send you created on the vocal track.

Now you can make the guitar track lower it’s volume every time the vocal track goes below a certain threshold or even though not necessarily desirable in this situation, make the guitar audible only on the parts where the voice exceeds the threshold.

[toggle title=”Video: How To Set Up Side-Chaining With The Dyn3 Expander/Gate”][youtube id=”CGdSYBVEuto” width=”600″ height=”340″ position=”left”][/toggle]

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Final Thoughts

This concludes it for the Dyn3 Expander/ Gate. It is a very effective way to create dynamic mixes and when used in conjunction with automation it can have a dramatic effect on the dynamics and realism of a mix. I am sure that after learning it, the unit will become one of the most used tools in you mixing arsenal.