Video editors are being called on to do more and mixing audio is one of those tasks. While advanced audio editing and mixing is still best done in a DAW and by a professional who uses those tools everyday, it’s long been the case that most local TV commercials and a lot of corporate videos are mixed by the editor within the NLE. Time for a second look at the subject.
Although most modern NLEs have very strong audio tools, I find that Adobe Premiere Pro CC is one of the better NLEs when it comes to basic audio mixing. There is a wide range of built-in plug-ins and it accepts most third party VST and AU (Mac) filters. Audio can be mixed at both the clip and the track level using faders, rubber-banding in the timeline or by writing automation mix passes with the track mixer. The following are some simple tips for getting good mixes for TV using Premiere Pro CC.
Repair – If you have problem audio tracks, don’t forget that you can send your audio clip to Audition. When you select a clip to edit in Audition, a copy of the file is extracted and sent to Audition. This extracted copy replaces the original clip on the Premiere timeline so the original stays untouched. Audition is good for surgery, such as removing background noise. There are both waveform and spectral views where it’s possible to isolate and “heal” noise elements visible in the spectral view. I recently used this to reduce the noise from a lawn mower heard in the background of an on-location interview.
Third-party filters – In addition the built-in tools, Premiere Pro supports any compliant audio filters on your system. By scanning the system, Premiere Pro (as well as Audition) can access plug-ins that you might have installed as part of other applications. Several good filter sets are available from Focusrite, Waves and iZotope. When it comes to audio mixing for simple projects, I’m a fan of the Vocal Rider and One Knob plug-ins from Waves. Vocal Rider is best with voice-overs by automatically “riding” the level between a minimum and maximum setting. It works a bit like a human operator in evening out volume variations and is not as blunt a tool as a compressor. The One Knob filters are a series of comprehensive filters for EQ or reverb controlled by a single adjustment knob. For example, you can use the “brighter” filter to adjust a multi-band, parametric-style EQ that increases the trebleness of the sound.
Mixing formula – This is my standard formula for mixing TV spots in Premiere Pro. My intention is to end up with voices that sit well against a music track without the music volume being too low. A handy Premiere tool is the vocal enhancer. It’s a simple filter with an adjustment dial that balances the setting for male or female voices as well as for music. Dial in the setting by ear to the point that the voice “cuts” through the mix without sounding overly processed. For music, I’ll typically apply an EQ filter to the track and bring down the broader mid-range by -2dB. Across the master bus (or a submix bus for each stem) I’ll apply a dynamic compressor/limiter. This is just used to “soft clip” the bus volume at -10dB. Overall, I’ll adjust clip and track volumes to run under this range, so as not to be harshly compressed or clipped.
CALM – Most audio delivered for US broadcast has to be compliant to the loudness specs of the CALM Act. There are similar European standards. Adobe aids us in this, by including the TC Electronics Radar metering plug-in. If you use this, place it on the master bus and make sure audio is routed first through a submix bus. I’ll place a compressor/limiter on the submix bus. This way, all volume adjustments and limiting happen upstream of the meter. By adjusting your mix with the Radar meter running, it’s possible to end up with a compliant mix that still sounds quite natural.
©2014 Oliver Peters
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