Mix With Confidence

25 Jan 2017

How Flux’s meters can help make the most of your mix.

Despite the mixing truism 'listen with your ears, not your eyes', there's no question that fully-featured metering software can speed up the mixing process. Not only can it point your listening attention in the most productive direction, but it can also lend a hand when your monitoring situation isn't ideal -- as is frequently the case in real-world production scenarios, even at the highest levels of the industry. To demonstrate how metering can speed up your workflow, I'd like to explain how some of the facilities within Flux's Studio Session Analyzer plug-in can help with a range of practical recording and mixing tasks.

Let's start with the Magnitude Spectrum display. Because it has such fine frequency-resolution and can so closely follow a sound's spectral envelope, it's very good for tracing unwanted pitched resonances on drums. You see, although the percussive elements of a drum hit decay very quickly, pitched resonances take longer to die away, so you can quite easily identify them as lingering narrow-band display peaks. To appreciate what I mean, compare these two Magnitude Spectrum displays, the upper one showing a drum hit's onset, and the lower one showing how the read-out looks a moment later, during the hit's decay tail:

You can clearly see a strong 592Hz pitched resonance sustaining longer than the other frequencies -- I've hovered over this resonance with the mouse cursor to reveal its exact Hertz value. With this information, it becomes the work of an instant to notch out the resonance with EQ. Now, it has to be said that you can never be quite sure whether you'll nail the correct resonance first time (most drum sounds have several, only some of which may be problematic), so you always have to check the EQ's results by ear. However, the metering certainly makes this common troubleshooting task a lot quicker and more accurate by clearly highlighting the most likely culprits.

The Magnitude Spectrum's frequency precision also allows it to identify uneven bass lines, which is a problem frequently missed in project studios where monitoring-room resonances often obscure sub-100Hz level relationships. For example, upright bass recordings are frequently miked a bit too close to the instrument's soundholes, over-emphasising a narrow spectral region somewhere around 70Hz. If standing waves in your monitoring environment cause, say, a suckout around 70Hz or a boost around 100Hz, you may not even spot the problem. Under those circumstances, examining the levels of bass-note fundamentals on the Magnitude Spectrum display still lets you diagnose and treat this malady sensibly.

Moving on to the Vectorscope, this is a type of display that I use every day. Like a lot of project-studio operators, I don't have much space for recording in my own studio space, so I do most of my tracking on location. In practice that usually means that I'm having to monitor on headphones or using speakers/rooms I'm totally unfamiliar with, and that makes it extremely hard to gauge the balance and width of stereo signals. This is where a display like the Vectorscope's can be a godsend, because it provides a visual sanity-check. Without delving too far into the technical details, basically the squiggly blob you see in the middle of the display provides a representation of the stereo width. If I'm setting up a stereo mic pair, for instance, I'll usually be looking for a display something like this:

Or, even like this if I'm after quite a wide image:

But, if it starts looking too much like this, then it's an indication that I'm over-stretching the stereo image, destabilising the localisation of central sources and compromising mono compatibility:

Alternatively, if I see something like the following left-leaning display, it indicates to me that my left-channel preamp may be turned up too far, or that the stereo mic rig as a whole is pointing a little to the right of the sound source or ensemble:

At mixdown Vectorscope's also useful on a daily basis, because I often get sent multitracks to work on which have stereo audio files for every track, even though some of those stereo files actually only contain mono audio. Here again, you can easily identify mono audio with Vectorscope, because it shows you display like this:

By rebouncing stereo files containing only mono audio as new mono audio files, I can significantly reduce the strain on my hard drive, allowing more tracks to play back at once without data-bandwidth problems.

Finally, there's Nebula, a Spatial Spectrogram that plots energy distribution across the frequency response and across the stereo image simultaneously. What I find this most useful for is scrutinising reverberant signals -- things like room mics or the outputs of reverb processors. In many cases with reverb, you want a setting that feels reasonably well-balanced in stereo, but in practice it's very common for reverberation signals to 'pull' disconcertingly to one side or the other. Although a simple panning change is sometimes enough to sort this out, the problem is often more complicated, with only some frequency ranges drifting off-centre. While it's perfectly possible to deal with this by applying EQ to either the left or right channel independently, the tricky part is finding the right frequencies to address. This is where Nebula can assist you, because it makes any stereo-imbalanced spectral regions much easier to identify.

For example, let's say I like the basic acoustic signature and tonality of a certain reverb plug-in patch, but the stereo image feels a little wonky somehow. I might find that its Nebula display looked something like this:

In response to this, I might use EQ on the left channel only to cut at 150Hz and 8.5kHz (combating the displayed zones of leftwards bias) and to boost at 450Hz and 7.2kHz (counteracting the regions of rightwards 'lean'), resulting in a more balanced stereo spread, and a Nebula read-out more like this:

Again, any such EQ would be subject to the approval of my ears, but in practice Nebula makes this particular thorny processing job a whole lot less hit-and-miss.

So, in summary, continue to mix with your ears, but know when to reach for your meters to exactly identify and rectify the trouble spots in your tracks.

Words: Mike Senior