Need more music AND dialog in your mix?

Ducking with Waves C6

Today, I’m going to discuss how to use a ducker in any post production audio mix and specifically ducking music with dialog using Waves C6 Multi-Band Compressor with a side-chain.  I use duckers in virtually every mix, with a slight variation on how much gain reduction I allow them depending on the program and mix aesthetic.  I have developed a really nice technique for getting best results without ever even noticing that anything is happening (which is exactly what you want).  If you’re comfortable with the concepts of ducking and side-chaining, feel free to skip down to the “Technique” section.  This article does assume a basic understanding of compression and even multi-band compression to some degree.

Quick Summary of Ducking

Goal:  Whenever there is speech, we want to decrease the music ever-so-slightly to make room for the speech.  How do we do this?  One way is with a ducker.  A “ducker” is just a compressor that “ducks” one source when another source triggers it.  What we do is put a compressor on the music track or submix with a side-chain (see below) input from the dialog.

Basic Ducker Settings

The threshold control will be set low (around -35dB or -40dB) so that whenever there is actual speech, the compressor is triggered.  The ratio is set extremely low (in the range of 1.1:1), in order to have a gain reduction during speech of between 1dB and 6dB, depending on mix taste.  Some compressors use Range controls instead of ratio – this makes ducking even easier, since controlling gain reduction is the goal.

What is a side-chain?


A side-chain is simply a signal (in our case, dialog), which is sent into the “side” of the compressor (or key) to cause gain reduction on another signal.  In our case the signal passing through the compressor is the music (goes in, comes out processed), and the dialog is simply used to determine when the gain reduction should happen (keying).


Until today, I would use two instances of the Renaissance Compressor for ducking music with dialog or voice-over.  The first would be set to a quick release (5ms) and would give the impression of increasing the level of the dialog without actually raising anything.  It does this by making imperceptible gain reductions in the music whenever speech was present.  The fast release time allows more aggressive gain reduction when needed.  The second ducker has a slower release time (400ms) which makes the music feel a little softer during the speech, but is still able to do it without any noticeable change in music level.

Another common effect for the music bus might be an EQ to reduce upper-midrange frequencies in the music to make room for the voice.  The EQ would, of course, be in effect at all times.  I have thought about sending a feature request to Waves to add a side-chain to the C4 Multiband Compressor so that I could set it to reduce only the upper-midrange band  when the voice was present.  This would eliminate my need for the EQ as well as one or both of the RComp duckers.  They must have read my mind and then went way above and beyond with the C6!

Waves C6 Multiband Compressor

The C6 is set up like the C4, or most 4-band compressors, but then they added two floating bands with separate parametric control, which you can place anywhere along the spectrum over top of the original four bands.  That’s pretty cool in and of itself!  Then they added the side-chain with more control than you ever imagined you might need.

You can choose to trigger each band separately from either “Internal” (in our case, the music) or “External”, which is the SideChain (in our case, the dialog).  I had no idea!  So what I ended up doing was using the regular four bands like I might use the C4, to gently balance the various tracks of music and increase overall continuity.  For example, if one piece of music has a strong shaker or high hat, the high band compression can help keep that in check (speed up attack and release on that band), or the low band might keep a heavy bass in check.  Then, I put the two floating bands in “External” mode to key them from the dialog.  I put one band around 2kHz, wide Q and 6dB of gain reduction.  The other band, more narrow with 2dB of gain reduction down lower in the voice spectrum.

In the end, I didn’t use any EQ on the music sub, but I did keep my fast-release RComp ducker, because I just really like the performance of it.  I could have done the whole job with just the C6.

Recently I was asked to pick one audio plugin as a “desert island” plugin.  I now have one.  If you’re looking for easy-to-use plugins that sound great, I still recommend the Renaissance bundle from Waves, but if you’re ready to step up to an incredibly versatile audio processor, give the C6 Multiband Compressor a spin.

Check out more Waves plugins and save 10% with this referral link:  http://refer.waves.com/OZry

Comments?  Find me on Twitter:  https://twitter.com/MichaelAudio

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