By Bob Kirschner
I record and edit dialog on a daily basis for podcasts, TV shows, commercials and corporate projects. Cleaning up dialog can be very challenging, especially these days as the COVID pandemic has completely changed the way we work. Much of the dialog I work on is now recorded from people’s homes: either from a prefab vocal booth if we’re talking about professional voice actors, or from a closet turned into a makeshift booth, or simply from someone’s office or bedroom.
The quality of recorded dialog is determined by not only the equipment used but also by the acoustic properties of the room in which the dialog is recorded. A room with lots of absorptive material will usually result in a much cleaner, more direct sounding recording. A room with lots of reflective surfaces will result in dialog that sounds echoey, distant and indistinct - a real problem for audio engineers and for the listening audience!
So depending on what the dialog sounds like, I’ll look to my arsenal of audio plug-ins to clean up and sweeten the sound. Fortunately, there are a bevy of excellent plug-ins developed by a variety of manufacturers specifically for this purpose. I’m going to highlight some of my favorite plug-ins as well as a bit of how I approach dialog clean up.
De-Reverb
For my first step, I’ll listen for any problems with room reflections that make dialog echoey or distant-sounding. This is a very common problem for anyone not recording in a professional vocal booth. (Fun fact: Until only a handful of years ago, audio engineers had to rely on noise gates to try and remove ‘reverb’ (room reflections), which was not very effective for this. But now there are intelligent De-Reverb plugins which analyze the audio and can remove just the reflective parts. This development was a game-changer for dialog clean up!) My go-to plug-in for this is Izotope’s De-Reverb, part of their RX audio repair bundle.
When working with De-Reverb, or any audio repair plug-in, it’s very important to compare the result with the original and be sure you’re not overdoing it. Too much De-Reverb processing can easily kill the essence of dialog. As a general rule, cleaning up dialog is always a balancing act, you want to remove the problems but you don’t want to lose the life of the voice. Over processing can result in things like muddiness, underwater-sounding side effects, syllables getting chopped off, and other nasty problems. My advice is to always err on the side of caution! When in doubt, better to under-process then over-process.
Plosives
Plosives are low-frequency (bass) noises caused by a voice producing a hard consonant (usually a ‘p’) with lots of air directly into the mic. A good pop filter properly positioned on the mic (about 2 inches away) will prevent many plosives from being picked up. But when they do get recorded they need to be dealt with. Since plosives are a low frequency problem, and the voice is more present in the mid-range, a high pass filter can usually knock out even the most egregious culprit. When I clean up dialog, I’ll always keep the Avid EQIII High Pass Filter open and ready to go, set to a corner frequency of 150Hz and a 12dB slope, so I can quickly zoom in on the problem and filter it out. I may need to adjust the frequency of the filter depending on the voice (male vs. female) and the degree of the offensive sound.
Mouth Noises
Another common dialog issue is the unintentional but frequent noises that the human mouth makes - lip smacks and mouth clicks. As it turns out, some voice actors never have a problem with this, while for others lip smacking is a regular occurrence. (A pro trick to stop lip smacking - eat a piece of green apple, it usually stops the smacks in its tracks.) So what do we do about it? Apply a bit of Izotope’s Mouth De-Click plug-in. This little piece of magic will quickly remove just the problem smacks. But like all dialog clean-up, be sure to compare the before and after so you don’t make the voice too muffled. I’ll almost always use less processing than the plug-in’s default setting.
Sibilance
The last dialog problem I’m covering, and this one can be the most difficult to correct, is sibilance. Sibilance is the high-frequency cousin of plosives - a problem caused by producing hard consonants (commonly an ‘s’) that results in an overly bright and painful-sounding syllable. Sometimes you may even hear someone ‘whistle’ their ‘s’ - an extreme example of sibilance. Fortunately their are tons of great de-essers that are designed to fix this common problem. BTW de-essers have been around since the beginning of professional recording, but now we have some very advanced plug-ins that can do things like ‘look-ahead’ and tackle the problem without any delay. My go to de-esser plug-in is the Fab Filter Pro DS. It’s extremely powerful and very user friendly. But my secret trick for conquering sibilance is the McDSP SA-2 Dialog Processor. This plug-in recreates a unique hardware processor used by film mixer Mike Minkler for dialog sweetening. It simultaneously limits at five specific frequencies that are common problems for dialog. You can dial in the amount of processing for each frequency and control the overall shape. I typically use this on my dialog bus after individually de-essing dialog with the Pro DS.
That’s it for now! I hope my plug-in recommendations for dialog clean up help you achieve high quality results.
