Quick and Easy Dialogue Cleanup with RTAS

Quick and Easy Dialogue Cleanup with RTAS

On Star Trek Into Darkness I had the opportunity to break out of my usual Assistant Editor responsibilities and tackle a new experiment in temp sound editing. Will Files, Matt Evans, Robby Stambler and I formed a new mini-department within Editorial that was tasked with temping out the Editors’ sequences and mixing them in 5.1. There’s a lot to the process that is new and interesting, and I hope to get another post up soon that more fully flushes it all out, but for the moment all I want to talk about is a method for basic, global dialogue cleanup that is probably old hat to some (and par for the course for professional sound mixers), but was new and amazing to me.

This tip comes courtesy of Will Files, who as a loan-out from Skywalker Sound was the guy who guided this whole process on Trek and helped teach me, Matt, and Robby the ropes of the sound world.

RTAS Is Your Friend

Before this show, I didn’t really know what RTAS was useful for, much less how awesome it really is. It allows you to use many of the AudioSuite plugins that you would normally apply to a clip, and apply them to an entire track instead, without rendering (thus the RT in Real-Time Audio Suite). Up to five RTAS plugins can be chained together per track. When applied to dialogue tracks, you can chain together 3 RTAS plugins that will make your dialogue much more understandable and leave more room in other frequencies for your sound effects and music.

So, to get started, you have to show the expanded audio controls in your timeline, and make your track size big enough that you see the little RTAS boxes:

RTAS

You can see that I have an EQ, a Compressor, and a De-Esser, in that order, on my dialogue tracks.  Let’s go through them:

1) EQ

The EQ you add here is basically a band pass with a little customization. Everything below 60Hz is gradually stripped away, as well as everything above 12kHz. This is because your typical dialogue won’t produce any audio in those frequencies that you want to keep, but by throwing it away you can start to address issues of boominess, high frequency hiss, and other technical problems with your production audio that get in the way of understanding the dialogue.

Aside from the band pass, this EQ also lowers frequencies around 120Hz by 2db, and raises frequencies around 4kHz by 2db. Again, this helps with boosting the frequencies of your dialogue that are most useful for comprehension, and removing frequencies that tend to get in the way, but without being as blunt as the band pass since these are frequencies you do want to hear.

RTAS EQ

2) Compressor

Now that you’ve removed unwanted frequencies, it’s time to normalize the volume. For that you use a Compressor, which will actively limit how loud your dialogue can get. If it gets too loud and crosses our set threshold, the Compressor will bring it back in line. The more the volume goes past the threshold, the more it will be reined in. This helps make sure there are no loud surprises in your dialogue, and will save you some of the hassle of mixing loud clips down to a more comfortable listening level.

In this case, we’ve modified three of the settings from their default states:

  1. Knee = 6.0 db.   This adds a little curve right at the threshold point, so that the ratio of a loud input level to its compressed output level is approached more smoothly. Without it, the compression would switch on at full force when the volume crosses the threshold. For a better explanation of this, read this article.
  2. Threshold = -20db.  By moving this up 4db from the default -24db, we’ve allowed our audio to be a bit louder before it activates the compressor.
  3. Gain = 4db.  This knob controls the output level of all audio passing through the Compressor, even audio that is below the threshold line. Since compression only reduces volume and can leave your dialogue levels feeling too low, adding a bit of make-up gain can help keep it at a good baseline.

Compressor

3) De-Esser

This one does exactly what its name implies, and helps with any S sounds in your dialogue that can be particularly piercing to listen to. It’s basically another type of compressor that handles high frequencies instead of high decibel levels.  On this we’ve set:

  1. Frequency = 5.4 kHz.  This means the De-Esser will be triggered for frequencies above 5.4kHz.
  2. Range = -3.0db.   When the De-Esser is triggered, it will reduce the gain of the signal by up to 3 db, which should help reduce the effects of any piercing audio.

De-Esser

As Quick as A-B-C

For those short on time, I’ve attached an Avid bin called Dialogue RTAS Effects.avb to this article which contains these three presets. They are labeled A, B, and C and should be applied to your RTAS chain in that order.

Tip: To quickly copy RTAS effects from one track to another, hold down Option and drag the effects you want to copy from one track’s RTAS chain to another.

 

 

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Thoughts from NAB 2012

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Thoughts from NAB 2012

I spent a day and a half on the floor of NAB 2012 (and a fun night at Media Motion Ball!). Here are some of the thoughts I had and things I'm excited about after visiting the exhibition floor.

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  1. Very interesting article as usual, Evan. Thanks for the write up!

  2. Fantastic, Evan. Thanks for diving into the dark arts of the audio world, and please share more when you can.

  3. Thanks!

  4. This is really wonderful – thank you

  5. Another thing worth mentioning: Thanks to the increased clarity and dynamics, the overall volume of the dialogue tracks carrying these RTAS increases about 2.5 to 3db. If you’ve mixed all of your sfx & mx around these enhanced tracks in individual reels and then build a long play and notice your dialogue sounds low, check to make sure the RTAS settings are in the new sequence. The settings do not transfer when cutting a reel into a newly created sequence. The only time they hold is when you duplicate a sequence that already has them.

  6. Good point!!

  7. WOW thank you so much for this. New RTAS convert!

  8. How does this process work in the grand scheme of sound editing for a video? For instance, when you have a video that has multiple people speaking and you need to EQ their voices differently and different clips need different compressor settings for normalizing? I’m coming from a workflow where I would make my edit in NLT program (which is now avid so i’m still very new) saving my last two steps of editing to a Audio pass and then finally a Color pass. For audio I’d send it to something like Adobe Audition or Soundtrack Pro to normalize different clips of dialogue, EQ voices, fx, etc as necessary, then send that back to my NLT. Now that I’m in Avid i’m not sure how this works. Your post has great information but I feel i’m missing something simple in the audio workflow. When and how do you do clip based audio treatment insteat of track based? Or do you even need to? Any advice would be greatly appreciated. I’m new to Avid so as I’m sure you can imagine I run into a lot of confusing instances where i just can’t figure out how to interpret what I want to do in Avid what I always did so easily in FCP.

    Thanks man!

  9. You can always add an individual EQ and/or AudioSuite effect to your clips, the RTAS is just meant to give you a better baseline from which to start. Most of our dialogue in Star Trek had an additional clip EQ, and in many cases an izotope denoiser, too.

  10. Oh ok cool. Thanks for the response Evan. Once I read your response I was still confused for a moment until I thought about how do I add effects to clips and then I realized I can just drag and drop effects from my effects pallet to the clip. Super elementry i suppose but when your just not use to that workflow and new to Avid/MC, the simplest things can be the most confusing to me 🙂 So thanks for helping me think through that. Can I ask you as well how Protools enters into your workflow? At what point do you move from MC to Protools and when do you just stay in MC? Thanks for your time man!

  11. In the past I’ve sent all projects to another audio dedicated program so my mind is not use to thinking about effects in my video program (what was FCP but now MC) as audio effects too. I’m use to thinking of effects in my video program as visual effects and then all my audio ones being reserved for the audio program. Trying to train my mind to think a new way now. haha. I feel like when I moved to Avid/MC my mind just got wiped of all common sense within video editing. 🙂

  12. Great Article, Evan. But there’s something I’ve always wondered about RTAS effects that I’ve never found a answer to. Do they carry over when you export the tracks? Since they are real time effects, I’m always worried that I’ll do all this nice EQing and compressing, it will sound great when I’m playing it, but when I export it, all those things won’t be be there in the AIFF tracks.

  13. Yep, RTAS effects will be included in any exported audio. The only time I’ve ever gotten tripped up is cutting one sequence into another and forgetting to put the fx on the new sequence’s tracks

  14. This is extremely helpful!! Thanks so much Evan!