AudioMedia - February 2009 - (Page 46)

OUDNESS Limiting LOUDNESS New Loudness Regulations ne of the annoyances most commonly expressed by viewers of commercial television concerns the relative volume levels of the programmes and the adverts slipped in-between them. One minute you’re settled on the sofa having set a comfortable listening level suitable for your favourite programme, only to have your ears flattened back to the sides of your head by the ferocity of the volume of the adverts. It’s easy to see why advertisers want to make them appear so loud; the ad break is the time you’ll be popping off to make a cuppa, and the ad agencies probably hope you’ll still be able to catch the gist of the latest scientific breakthrough in hair styling technology even when pootling about in the kitchen. There’s also an advantage for broadcasters – if the adverts are louder than the programmes, then the end of the of the commercial’s soundtrack is a cue to encourage the viewer to get back into the living room to follow the exploits of the latest medical or crime drama. STEPHEN BENNETT discusses what the new TV advertising regulations will mean to you. O Keep The R emote Handy The Advertising Standards Authority (ASA) received hundreds of complaints regarding the disparity in levels between adverts and the programmes funded by them. They found that the sound levels of these advertisements were, in fact, complying with the thencurrent recommendations drawn up by BCAP (Broadcast Committees of Advertising Practice), which stated: “Ads must not be excessively noisy or strident, and that studio transmission power must not be increased from normal levels during advertising.” However, the existing rules were obviously not fit for purpose as viewer complaints were still flowing in. The problem was exacerbated by widespread use of the technique that many feel is ‘infecting’ the sound of contemporary popular music – the use of limiters or maximisers to increase the apparent overall loudness of audio material. Existing regulations made extensive use of Peak Programme Meters (PPM) to measure peak output levels. These rules stated that material should not exceed six on the PPM, or four on ‘ads with a highly compressed soundtrack’. As you can imagine, these regulations, formed in the days before the likes of Waves’ L Ultramaximiser became the default last plug-in on the master output of a Pro Tools mixbus, were not really up to the task of monitoring the highly compressed audio of contemporary adverts. After consultation with interested parties, BCAP proposed new rules to accommodate this technological change and attempted to encourage broadcasters to measure the subjective loudness levels of ads, rather than simply measuring peak sound levels as has been the case in the past. These new rules were based on the following criteria: • Peak levels of sounds • Length of time sound levels are maintained • Different frequencies, or ‘pitches’, contained in the soundtrack Broadcasters will now be told that, “A consistent subjective loudness must be maintained between individual adver tisements, and bet ween the advertisements and programme and other junction material.” This is all well and good, but subjectivity can only go so far in ensuring that the public are not pinned against the back of the sofa when the adverts come on. So the new rules also give broadcasters much more technical guidance on how they can ensure greater consistency between advertisement and programme sound levels. The International Telecommunications Union (ITU) has drawn up recommendations on how to measure subjective loudness levels and these have been incorporated into the new regulations. Broadcasters will now have the option to carry out their testing in accordance with two ITU recommendations: using the ITU-R BS algorithms to measure audio programme loudness and true-peak audio level, and applying the ITU-R BS requirements for loudness and true-peak indicating meters. BCAP looked at a total of ten commercially developed monophonic loudness meters and algorithms (which were submitted by seven different proponents) for evaluation at the Audio Perception Lab of the Communications Research Centre in Canada. Ultimately, the algorithms chosen for the new regulations were based on the existing Leq (RLB) ones – which many manufacturers already incorporate into their products – but modified for multi-channel work. The regulations still allow for PPM meters to be used, but the maximum level of the advertisements must be at least dB less than the maximum level of the programmes to take account of the limited dynamic range exhibited by most material. 46 AUDIO MEDIA FEBRUARY 2009

Table of Contents Feed for the Digital Edition of AudioMedia - February 2009

AudioMedia - February 2009 Contents Recording News Post News Broadcast News GEO Focus: USA What's Up UK NAMM Review For the Record Project Profile: Hallelujah HHB CDR882 KORG MR-20005 Chandler Germanium Brauner Phanthera Final Cut: Lesbian Vampire Killers SE Electronics RNR1 The Royal Opera House Fairlight XYNERGI Limiting Loudness Product Sampler: Studio Consoles Video Guide AMSR News Stone Temple Pilots Fly Again Rode M2 Yamaha IM8 Series

AudioMedia - February 2009

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