Thoughts by Ian Palmer:
Anyone who knows me will know that 4 years on I am still madly in love with iZotope’s RX noise reduction package. So it is rather exciting to see what else this company can do. I had high hopes for this meter after hearing about its launch. If only I could do this review in three words, as in “It’s bloody good”!
Just to note, that I am reviewing Insight on an iMac running OSX 10.7.4 with ProTools 10.3.3, in stereo and from the point of view of a Dubbing Mixer in Europe using the forthcoming R128 mixing specifications.
Installing and registering the plugin is very simple and straightforward, as was finding it in the Sound Field folder. I easily located the preset folder and changed the settings to R128. Or BS ITU1770 Loudness Meter with History Graph EU. It’s easy enough to add my own presets and name them, but for the inexperienced I think the names could be simplified.
I really like the UI of Insight. Whilst it is busy, it is also easy to navigate quickly. It is customisable so that you can also make it as crowded or simple as you wish. The display options are Levels, Loudness History, Spectrum Analyser, Sound Field and a Spectrogram. It’s really interesting to see things that previously I had to listen for, like a mix being bass heavy. Tis is useful for those of us in smaller rooms and with smaller speakers wher such things can be difficult to hear. I welcome the phase meter in the Sound Field, something lacking from the likes of Waves’ WLM. The Loudness History gives you the ability to quickly identify where in a mix a problem might lie. Clicking on the plus button expands (any) the display where you can take a screenshot or even copy a very long list of measurements. Great for attaching to a mix delivery to placate those evil number crunching bureaucrats in QC.
A few nights ago, I was struck by an idea that hadn’t occurred to me previously. I was prepping for a presentation on loudness metering at a game development studio that would take place the following day. It was a question…
Would bit rate or sample rate reduction affect the loudness measurement of sounds metered using ITU-R BS.1770?
Both are practices common to game audio. If there actually is a potential difference, it would be important for people to be aware of that. Never blindly trust your tools. We use metering systems, because it is unwise to rely only on our ears. Likewise, trusting a metering system in a situation it may not have been designed for is equally foolish. With everyone constantly pushing for higher quality and higher resolution audio, I doubt there was an abundance of concern during the development of ITU-R BS.1770 for possible applications in lower resolutions.
Guest contribution by Owen Green
[This is the second of a two part series on loudness, mixing, metering and the new ITU loudness spec]
The New Loudness Standards, and What They Might Mean for Us
Depending on the field in which one worked, standard production practices have tended to be orientated around peak normalisation of material. That is, lining up recordings by their peak level; in music, recordings are now often lined right up 0 dBfs; in broadcast a common specification is to peak at -9 dBfs (which allows some headroom in recognition of the fact that analogue QPPMs don’t truly measure signal peaks). As is hopefully clear from last week’s article, this has almost no bearing on how loud we perceive the material to be.
A set of new recommendations has been developed since 2006, and are now becoming standard or legally stipulated practice in some industry areas and countries. It is therefore worthwhile to get a handle on what they mean, and how to use them as soon as possible.
The core proposal comes in the form of a recommendation from the ITU (International Telecommunications Union) on how to measure the loudness of a signal (ITU BS.1770-2). Local bodies, such as the EBU in Europe and ATSC in the US, have then published (pretty similar) guidelines on working practices derived from the ITU spec. The common thrust of these proposals (actually, now rules in some places!) is that they enable a move away from normalising by peaks to normalising by (approximate) loudness:
So, material that has been more compressed in dynamic range (so as to appear louder when peak normalised) loses its ‘advantage’ by being reduced in gain
so that its perceived loudness is on par with more dynamic material.
Guest contribution by Owen Green
[This is the first of a two part series on loudness, mixing, metering and the new ITU loudness spec]
Understanding the complex relationship between sound level and perceived loudness turns out to be very important to us as designers of sound for a number of reasons:
- Our perception of loudness is not constant (or even remotely linear) at different frequencies, so it is possible to have high level signals that nonetheless sound weak (and vice versa) depending on their frequency content.
- The levels at which we monitor in the studio have an impact on how we hear our work, and consequently on how the work translates to different spaces and systems, because our relative perception of frequency is not constant across different levels.
- Our judgement of frequency balance and loudness is not constant with time. This is particularly true if we tire our ears out with working – it becomes harder to make reasonable decisions.
- To get the best out of our equipment, we need to understand how it works and interconnects; this means knowing about the various different dB scales we will encounter, and how they should align.
- Recently, a number of areas have adopted a recent ITU recommendation on a loudness (rather than level) based form of metering and specification for broadcast. Other sectors are investigating following suit, so it is quite likely that this will be a standard and required practice.
Insofar as the ITU recommendation arose as an attempt to circumvent the sonic race to the bottom of the ‘loudness war’, this whole issue of how we relate the levels of our equipment, our perceptions of loudness and our working practices occurs at a complex intersection of technology, psychology, aesthetics, economics, politics, philosophy, etc…
Levels and dB
Image by flickr user Cubosh (Chris Dlugosz)
It’s February 1st. That means it’s a new month with a new featured topic. This time around, we’ll be digging into the subject of loudness metering.
When we refer to “loudness” we’re talking about those specific documents you’ve been hearing more and more about over the last few years: ITU-R BS.1770, EBU-R128, and ATSC-RP A/85. Whether you know what all of that means or not, we’ve got you covered. Next week will be the an introduction to loudness…the first of a pair of articles on metering in the beginning of the week, a free webinar on the 9th, and the second of the pair on metering coming shortly after that. Even if you’re familiar with the subject, you’ll probably find something new to learn in the coverage. The rest of the month will be dedicated to people talking about how loudness metering affects the work we do, both aesthetically and technically.
A quick heads up, we’ll also be giving the site a new look and migrating it to a new server towards the end of the month. [Remember when we mentioned this waaaay back in October?] The site will be down for a bit while we do that, but we’ll warn you ahead of time. It will help us tweak some functionality, as well as organize things a little better…making it easier for you to keep track of the featured content.
If you think you have something pertinent to share with the community on this subject, you are encouraged to do so. Next month, we’ll be focusing on the intersection of sound design and music. If you’d like to contribute to either topic, send an e-mail to shaun.at.designingsound.org to get the ball rolling.