We sometimes criticise the effect the rich visual feedback a DAW can have. ‘Just use your ears’ is a common theme. In this article Julian considers the benefits advanced metering brings to us and looks at some examples where metering has advanced beyond a more complete version of what we already have into new ways of seeing subtler relationships.

It Started With Computers

My first steps in music production were based in recording audio onto magnetic tape and my earliest interest in anything digital came from the desire to use MIDI. I wanted a sequencer and at that time hardware sequencers were still very relevant. But I decided to take the computer route because I could see that the visual feedback was going to be so much better.

This desire for greater visual feedback is still everywhere. Being able to understand what is going on at a glance rather than having to interpret information makes everything easier. Metering is important, and in this article I'm going to consider what it is about good metering that makes it good and how visualising audio is getting deeper into our sessions than ever.

Traditional Meters

The most familiar meters in audio production are those which indicate the presence of a signal. Something as simple as an on/off ‘you have signal here’ meter is invaluable when it comes to fault finding. These meters, which originally were single light bulbs or LEDs, still find a place in DAWS. For example, a MIDI activity meter or, in Pro Tools, the little square flashing light found on a Basic Folder track to indicate the presence of audio in the member tracks.

The moving coil VU style meter and ladder style level meters go further than merely on and off and indicate the level of signals rather than just their presence. This gets complicated and the relative merits of VU meters, compared to PPMs, compared to Sample Peak and RMS meters is important, but I'm not going to discuss it here. For a detailed look at the history and variety of level meters available check out our article Understanding Advanced Metering In Pro Tools.

For a really visual illustration of the difference between different styles of metering watch the short video below in which we have all the available metering styles running simultaneously on the same audio in Pro Tools.

Given all of the advantages in terms of flexibility and clarity of modern meters, you might think that the old-fashioned moving coil meter was no longer useful, but anyone who's used a real one will understand how easy to use they are and while they are less useful than many of the alternatives when it comes to monitoring levels, they are particularly useful for representing the familiar metering on well-known hardware in skeuomorphic plug-in designs. For displaying gain reduction in particular, they can hard to beat.

Ways of displaying information about our audio have gone far beyond what we found on hardware. A row of bargraph meters can accurately display the relative levels of a surround mix but it takes some effort to interpret that into meaningful information about the apparent position in the soundfield. The ‘jellyfish’ display is a great way of presenting such information in a more digestible way (hopefully that’s the only time I’ll use ‘jellyfish’ in the same sentence as ‘digestible!). We have plugins dedicated exclusively to presenting information about every possible aspect of an audio signal. Nugen’s Visualiser, iZotope’s Insight and SPL’s Hawkeye are all examples of highly customisable metering but metering has progressed beyond the level of detail with which it can interrogate a signal. It now also looks to combine and collate information from across a session.

Shouldn’t We Be Using Our Ears?

But shouldn't we be using our ears? Well of course we should and a meter, when used properly, should be used to confirm and to verify what our ears are telling us. Never to guide our decisions without reference to what we're hearing. This sounds obvious, but it is too important not to say here. But if all that matters is how something sounds, why do we even need meters?

The principal role of a meter is to warn us of faults and errors which we might not notice without them. The most obvious of these is the humble clip warning light. An additional layer of complexity to something which ought to be simple is the possibility of inter-sample peaks, giving rise to true peak metering. Loudness workflows have introduced yet another necessary meter type. Calibrated monitoring and practice can lead to a mixing process which is very instinctive and results in mixes, which can be very close to target specs, but you still need a good meter and while you can mix to loudness specs using a loudness meter which just provides you with a numeric read out of momentary short-term and integrated loudness, having access to a loudness history is particularly useful. Vis-LM from Nugen is particularly successful in this area, though alternatives of course exist.

Meters Which Aid Learning

One of the most significant changes which has come to audio metering in recent years is the proliferation of scrolling history graphs, which give insight not only into instantaneous level, but also, how that level has changed over time. The gain reduction history graph, as found in many compression and limiting plug-ins, gives an insight into the role of attack on release times in particular, and presents information in a way which isn't easily accessed using other means. I know when I was learning, and particularly when I was teaching compression how helpful I would have found this as a way of presenting the role of compression in shaping sounds.

You could argue the same point about frequency analysers, though I’ve always thought them a double-edged sword when it comes to learning about audio. They are extremely useful for learning about the distribution of energy through the spectrum and for understanding the harmonic series, but too often they are presented as a more useful than they are in informing EQ choices. However information about frequency can be brought together in useful ways using spectrum displays, which I’ll come to later.

Meters Which Bring Information Together

I’m using the word ‘meter’ broadly, to mean something which displays information about an aspect of audio signals. Being able to bring together information from disparate sources and display them together can be a great benefit during mixing and a simple illustration of this would be Evergreen Audio’s Massive Meter plugin. It’s a very specialised tool and something not many people need, but for those working on really large scale projects the ability to bring level meters together helps enormously of you have enough of them. But of more relevance to people working on smaller projects is the ability to collate and combine information from multiple plugins together into a single interface.

A good example of this in Pro Tools is the ability of the channel gain reduction meters to display the combined gain reduction of multiple dynamics plugin in a single meter. At its simplest it can present the combined gain reduction of two compressors on the same channel, not an unusual arrangement, many people combine a fast FET style compressor with a slower optical style and while each plugin has its own gain reduction meter, the channel meter combines them together. Check out the Metering tab of the Pro Tools preferences to see how these meters can be used in other ways.

A second example is the channel EQ display which can be displayed in the mixer window in Pro Tools. I ignored this feature for a long time, thinking that it was just showing me something I could already see in my EQ plugin’s UI but if you combine multiple EQs on a single track, their combined curve will be displayed. Unfortunately support for this feature is patchy among third party plugins but it is supported in all Avid EQs and Fabfilter’s Pro Q3.

But rather than bringing together information between plugins on the same channel, it’s when bringing together information from plugins on different tracks that things get more interesting. Back in 2018 we predicted more and more communication between plugins across sessions and that’s what we’ve seen. Plugins such as Auto Align 2 which gathers information from other tracks on which instances of Audio Align is instantiated and uses this to create correlation ‘heat maps’ of the audio content through to plugins like Fabfilter’s Pro Q3 and Sonnox Claro which uses  data from other tracks to identify accumulations of energy in particular areas of the spectrum, given our recent article on auditory masking. This information is particularly useful in informing choices when mixing.

So Should We Mix With Our Eyes Now?

I’m definitely not saying that metering, or any kind of visual display of a session’s audio, is anything other than complementary to the decisions you make with your ears. However in the same way that a clip light is a warning of a potential issue which credits further investigation, other visualisations such as warnings about potential EQ clashes, correlation meters showing out of phase content or even intelligibility meters warning that the dialogue might need checking are all useful additions to our processes.

Is there any information you think would be beneficial if it were shared between channels on sessions via a plugin?