In October, the main UK broadcasters changed their production specifications in order to transition from tape to a fully digital workflow.
Within the new technical standard the broadcasters have finally adopted the same system of metering audio not just for programmes but for commercials.
This was after years of the stations using multiple approaches and different technologies to try and prevent commercials sounding “too loud” next to their programmes.
At last sound houses can easily place a mix between two other ads and know that the relative volume will be exactly the same on air.
To get an idea of how difficult this was before October, there used to be 12 different levels at which a commercial had to play out!
What’s new about R128?
So what is new about R128, apart from the fact that it’s the same for all the main broadcasters?
The previous metering system, which was called Peak Program Meter or PPM, measured (as you’d expect) peaks.
The magic number to peak to was 6PPM, so in the studio the engineer would try and hit 6 as often as he could, usually aided by a compressor which allowed them to pump up the volume but squash the peaks back to 6, thereby making the whole thing louder.
R128 works with average loudness, rather than peaks. The meter starts measuring the loudness at the start of the commercial and you take a reading at the end. The magic number here is -23 LUFS.
What this means, since the R128 meter measures energy rather than peaks, is that there’s no way to make the mix louder using compression. So commercials should sound better, as they’ll be largely less compressed.
Audio challenges of R128
R128 does present some challenges to commercial audio production. In theory, if you have a soundtrack with quiet bits and loud bits, this should work well.
You can make the loud bits fairly loud as long as your quiet bits are still loud enough in contrast. However, if you have a music track throughout your film, you may have a problem.
Since the structure of pretty much every music-led piece of advertising is a build to a big finish for the packshot this means that a lot of your average energy has been “spent” at the end.
This will mean that your commercial starts “quiet”.
This is further exacerbated by the eq curve built into the R128 meter, which concentrates on the kind of frequencies where instruments like horns and brass live.
Get a string section and a brass section sustaining notes, and you have some careful mixing to do.
The particular challenges of commercials
Commercials are still judged by the client by their competition. What this means is that a soundtrack which starts quieter than the preceding audio (unless it’s creatively intended to be) is deemed to be too quiet.
If this happens the agency can expect an unpleasant call the following day.
What, therefore, are the measures to avoid this happening?
Well, obviously an ideal situation would involve always picking a track that doesn’t offend the R128 meter. But in reality, this isn’t practical. It’s hard enough for an agency to select and sell in a music track without having to consider how R128-friendly it might be.
But, if the track exists in stems or even as a pre-mastered version, that would certainly help. At least then you have the track before it was (usually heavily) compressed for release. Then in the studio, some careful balancing of volume across the piece is called for.
Of course, if the commercial doesn’t purely depend on a track at full whack for the duration, and there are dynamics in the arrangement as well as the volume, then you stand a good chance of getting through to air unscathed.
The key is to make sure you are mixing your spot in a studio with an R128 meter and, if in doubt, compare it in a break with some of the competition.
Owen Griffiths
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