Own a Linear Acoustic product and wondering if you are compliant with the updated regulation? The simple answer: You are!
For a more in-depth explanation of the new regulations and product-specific details, please click on the "Continue Reading" link below.
The ATSC has recently updated and delivered to the FCC an updated version of its A/85 Recommended Practice – aka "Techniques for Establishing and Maintaining Audio Loudness for Digital Television" – which includes an update of the referenced ITU (International Telecommunications Union) recommendation for algorithms to measure audio program loudness and true-peak audio level.
Since the CALM (Commercial Advertisement Loudness Mitigation) legislation is based upon A/85, whenever A/85 is updated, CALM follows automatically.
This has left television broadcasters wondering what influence the new recommendations will have on them and whether or not their current processing and metering equipment is capable (or can be updated to become capable) of complying.
It is important to understand that these changes affect loudness metering and measurement, NOT loudness processing.
It is also helpful to understand that the difference between the original ITU-R BS.1770-1 and -2 involves the refinement of gated measurements and the inclusion of a technique called "relative gating". Relative gating means that gating will occur at low audio levels which change relative to the average audio levels. You will sometimes hear -1 referred to as "fixed gating" and -2 as "relative gating" accordingly.
ITU-R BS.1770-3 introduced a change that removes a filtering option that was present in the -2 standard. Linear Acoustic products have never employed this optional filter, and so this change (with one exception – please see the detailed information on the LQ-1000™ Loudness Quality Monitor below) does not impact our customers.
We strongly recommend that all television broadcasters become familiar with A/85:2013 which is available for download directly from the ATSC website via this link: http://www.atsc.org/cms/standards/A_85-2013.pdf
Specific Linear Acoustic product information is provided below.
AERO Series Processors
Since the new recommendations pertain to loudness measurement and not to loudness processing per se, any past or current Linear Acoustic processor is capable of delivering compliant audio if properly installed and configured. This includes all OCTiMAX™, AEROMAX™, AERO.one™, AERO.air™, AERO.lite™, AERO.100™, AERO.2000™, and AERO.1000™ products and will apply to future products as well.
While the processors themselves can all provide compliant audio, some have built-in ITU-R BS.1770 utility meters. These meters are not intended to be a substitute for a dedicated LKFS meter capable of monitoring demodulated audio or generating loudness logs. Rather, they are provided to make matching the final output level of the processor to the dialnorm quick and easy, which, when done properly, results in compliant audio.
The meters included in AERO.100, AERO.1000, and AERO.2000 are ITU-R BS.1770-3 compliant.
The optional meter in AERO.lite and the utility meter on the Final Stage adjustment screen of AERO.air products are short term (10-second) integrated meters and produce results that match BS.1770-2/3 meters within required tolerance, but do not contain Peak or True Peak meters and thus are not affected.
LQ-1000 Loudness Quality Monitor
The LQ-1000 Loudness Quality Monitor is (or can be easily made to be) fully ITU-R BS.1770-3 compliant.
LQ-1000 products with serial numbers below 34-1000 must up updated to software version 1.10.12 in order to be -3 compliant. This is a free update for registered users of our website. If you need the software and are not yet a registered user, please click on the "Register" button at the top of the home page.
Units with serial numbers of 34-1000 and higher are already compliant and need no additional updates.
LQ-1™ Loudness Meter
All LQ-1™ units are fully ITU-R BS.1770-3 compliant. No additional updates are needed.
For the reasons explained in detail earlier, selecting an ITU.R BS-1770-2 measurement in the LQ-1 will result in a measurement that is also -3 compliant. Since Dolby® Dialogue Intelligence™ is recognized as an acceptable means of measurement in the latest version of ATSC A/85, it too is inherently CALM-compliant should you choose to employ it.
LAMBDA™ and LAMBDA-II™ Digital Audio and Metadata Monitor
The LAMBDA™ and LAMBDA-II™ are short term (10-second) integrated meters and produce results that match BS.1770-2/3 meters within required tolerance, but do not contain Peak or True Peak meters and thus are not affected.