Editing Hack for Car Dialogue (with Izotope RX)

Remember the iconic movie Speed with Keanu Reeves?

While the practical choice of filming on a moving bus created a thrilling visual experience, the constant fluctuation in engine RPM rendered most, if not all, dialogue unusable.

That movie is as old as I am (don't look the year up)! Back then, the solution was a time-consuming ADR (Automated Dialogue Replacement) process.

One of my teachers worked on the ADR for this movie. It took Keanu nearly a full day just to deliver one phrase with the right performance. Allegedly, some chairs were thrown in frustration.

Thankfully, audio technology has come a long way, so no need to duck and cover as we have a powerful weapon in our arsenal: Izotope RX!

The Woes of Car Dialogue: Battle Engine RPMS

Location sound recording inside a moving car presents a unique challenge.

Engine noise fluctuates with speed changes, creating an inconsistent sonic backdrop that wreaks havoc on dialogue cohesion.

Every edit point becomes a potential battleground, with very obvious edits for each different take.

This process is not only expensive and tedious but can also sap the energy and authenticity of the original performance that is difficult to recreate in a studio environment.

But here's where the sound supervisor will love you and keep on booking you for your dialogue editing skills!

Izotope RX to the Rescue: A Multi-Tool Approach

Izotope RX Advanced offers a powerful suite of tools to salvage dialogue from the clutches of pesky engine noise. However, have different noise reduction plugins on hand allows you to get farther. Here's my multi-tool approach:

1. Spectral Repair & Ambience Match: Extend the dialogue audio clip length and send it to RX. Our goal is to remove the dialogue while preserving the car's natural driving performance. This can be achieved with a combination of Spectral Repair and Ambience Match.

2. Waves Clarity VX Pro (or Dialogue Isolate/Hush Pro): Here's where personal preference comes in play. I favor Waves Clarity VX Pro for its superior detection and ambience preservation capabilities compared to Dialogue Isolate (although Isolate is still a powerful tool. Since writing this, RX 11 Dialogue Isolate and Hush Pro are worthy contenders). Using either plugin, selectively lasso only the dialogue sections and process out the vocals.

3. Complex vs. Static Ambience Match Profiles: With the dialogue removed, it's time to rebuild the sonic landscape. Take an Ambience Match learn profile of different car sound sections that doesn't have dialogue in it. If enough information is available, consider creating a "complex" learn profile to add back on top of the removed dialogue (deselect "output only"). This complex profile helps maintain a more natural feel compared to a static ambience paste.

4. Spectral Repair Cleanup: Polish the extracted ambience with Spectral Repair to remove any remaining unwanted noise or artifacts or to better blend elements together.

Once you're happy with the isolated ambience, send it back to Pro Tools and render it.

Long Fades are Your Friend: Seamless Blending & RPM Consistency

Now that you have extended head and tail audio, it's time for some creative editing magic. Create long, equal-gain fades throughout the scene, ensuring smooth transitions between edits and ambience sections.

Depending on the editing style and cut speed, you might even be able to remove some of the RPM noise completely if there's a consistent background ambience that plays underneath.

The key to success in car scene dialogue editing lies in the power of very long fades in and out around the dialogue. By embracing this technique, you can seamlessly blend the extracted ambience with your dialogue, creating a cohesive and intelligible soundscape. 

The Izotope restoration is only a small part of the process, the rest lies in your dialogue blending skills in the edit. But the extra care and time spent into it beats the administrative and additional cost of going the ADR route.

Being a dialogue editing god will spread your name like wildfire for these "fix it in post" directors.

Or maybe anti-ADR Christopher Nolan's go-to dialogue editor —who knows!

Beats having a chair thrown around your recording room... allegedly.

If you want to learn more dialogue editing hacks, watch me problem-solve for no ADR possible shows at Post Audio Pro!