ADPTR Metric AB is a fantastic plugin that gives you a variety of visual tools which help draw your attention to problematic points in your mix. It also allows you to easily compare your mix to multiple reference tracks in your genre. This is particularly important if your studio has less-than-perfect acoustics.  In this review I’m going to be talking about what I like and don’t with the plugin, my basic workflow, and weather or not it’s worth the steep $199 price tag.  Before you begin with Metric AB, I recommend enabling tool tips from the gear icon menu.

My Workflow

Metric AB runs as a VST on your master channel.  One of the things that makes Metric AB such a joy to work with is the ease at which you can compare multiple reference tracks. Referencing tracks is critically important. As you listen to your tune over and over, your ears will get accustomed to that sound and it becomes increasingly difficult to be objective. Reference tracks give you a commercially successful mix goal in your genre. Additionally, you’ll learn a lot just by trying to get your mix “right.”

1. Pick good reference tracks: Select up to 16 well-mixed tracks you love in the same genre you’re composing. In this blog, I’m working on my new self-titled house track so I dragged in six different tracks for comparison.
2. Set cue points: Set separate loops for each individual reference track (intro, breakdown, drop for example).  
3. Match volume: Starting with the drop or chorus which are usually the loudest parts, select “match volume.” In a few seconds Metric AB will match the volume making comparisons much easier. Remember that louder almost always sounds better, so this is a critical step. You have to match the volume separately for each reference tracks as each was mixed and mastered a different loudness. 
4. Select playback mode: You’ve got three options in Metric:  Latch, Cue, and Sync.
   1. Latch: latches Metric’s playback to the DAW transport.  This means whenever you play or pause your DAW, it will play or pause the reference track.  This is the default, and usually what I do.
   2. Cue: Same as latch mode, but it restarts playback from a cue point when you toggle between your A and B tracks.
   3. Sync: Sets playback location from the DAW timeline (I.e.. If you start from 1:30 in the DAW, it will start from 1:30 in the reference track)

Now you’re ready to move on

I like to select a particular song section to work with and then move my way across the top of the screen, working from Spectrum to Loudness as indicated by the arrow in the below photo. Have a notepad out so you can jot thoughts about things that need fixing throughout the process.   As you’re in each of the sections, don’t forget to also click Mono and Sides under your volume meters to see how these aspects of your mix sound too.   

Mono is increasingly important.  Even if you don’t expect your track to be played on big club or festival sound systems (which are usually mono), your track may get streamed over Siri or Google Home, both of which are in mono.  Translatability (your track should sound good across a variety of speaker systems) is essential.

I also use the filters in each section to listen to the bass, mid, and high end frequencies.  The bass drives the dance floor, so isolating that can be particularly useful.  Mid frequencies often carry the melody, either vocal or instrumental. High frequencies provide crispness and interest to a mix. Isolating each using filters helps to focus your attention.

In each of these sections, Metric AB offers a wealth of visualization options as well as the ability to compare side by side or with the two tracks overlayed.   Experiment and see which works best for you.

Spectrum

In this section I’m seeing if my track has similar volumes to the reference track throughout the frequency spectrum.   I will check low pass, band pass, and high-pass filters (bottom right corner), and will also try the mono and sides.   If one area has too much or too little, I’ll make a note to go back and fix that later. For example, if my bass frequencies are hitting -2db on average less during the drop, I may want to turn up the bass tracks a little, or perhaps add a little via EQ in the master track.

Pro tip: By clicking in between the two volume meters in the upper left, you can toggle between the default range from 0 to -48dB (better for mixing) to 0 to -18db, which is better for mastering.

Correlation

Correlation helps you identify areas that might be suffering from phase cancellation (when one frequency is canceling out another).   Remember your monitor’s diaphragm (cones) can only go one direction at a time: if you have one sound that is telling the cone to push and another that is telling the cone to pull, both sounds will become muted.  Generally speaking, anything from 0-1 is good. A high correlation means you’re not having phase cancellation, while a negative correlation means sounds are canceling each other out.   

How do you fix phase cancellation? There are a variety of potential issues, but often ensuring your bass frequencies are in mono will help the problem.   In the next section, stereo image, you can quickly tell if your bass is in mono.

Stereo Image

Stereo image gives you a depiction of the left-right gain over the entire frequency spectrum: it shows you how wide your mix is.   This is important if you’re doing a lot of mixing on headphones, which tend to make mixes sound wider than they actually are. In general, you want a Christmas-tree shaped curve with it being narrow at the bottom (bass in mono to avoid phase cancellation), wider in the mid frequencies, then narrowing somewhat at the top.

Pro tip for sub frequencies: try touching your monitors.   Sub frequencies are long, and thus travel through the air slowly. You introduce latency just by sitting a few feet from your audio source.  By putting hand on the side of your monitors, you’ll know immediately when the sub is hitting. Another options is a subpack for immediate, tactile feedback. 

Dynamics

Dynamics describes how much range there is in your track from the quietest sounds to the loudest. Heavily compressed tracks sound “louder” but have much lower dynamic range.  Metric AB uses Peak to Short-Term Loudness Ratio (PSR) which is often used by online services to determine how much your track will be “normalized” in it’s final playback format. It measures the difference between the max peak volume and the integrated loudness over three second intervals.

How much dynamic range you want depends on the genre of music, the instruments involved, and your sound preferences.  For example, an acoustic piece may have a lot of dynamic range, while dance music tends to be more “squashed.”  The type of instruments affect dynamic range too: drums tend to have a much higher dynamic range than a pad, for example.  You can recognize these squashed mixes when you see their waveforms: they look almost like a tube of toothpaste.

Metric AB gives you several preset guides you can select from, depicted above by the red line.  I tend to like to start with the “competitive” preset which is a happy balance between a squashed mix and too little compression, but generally speaking 12-14 PSR is good for a mixdown, 7-8 PSR will give a loud master while retaining some dynamics, and 5-6 PSR is a good target if you’re going for hyper-compressed dance music.

Loudness

Finally, there is a loudness meter also with numerous presets to choose from.  I like Competitive as a good average setting, but your best choice depends on your genre and what platform you’re mastering towards.

Alternatives to Metric AB

Free Options. Good ol’ Spectrum in Ableton can do a lot,  particularly if you build a rack that quickly allows you to listen to sides, mono, low, mid, and high frequencies. If you’re looking for a little more flexibility, you can get the free Voxango Span plugin which is very popular.  If you’re using Ableoton Live 10 there is a Max For Live patch called Mix Matcher which provides a useful “pink noise” reference which is a good place to start when you’re doing initial leveling before you move on to specific reference tracks. 

iZotope Insight 2 for $199. I’ve been a big fan of iZotope products: I personally own and use Ozone 8, Neutron 2, and Nectar. You can read my review of the Ozone 8 & Neutron 2 bundle here.   iZotope offers a generous 50% student discounts, make outstanding plugins, and have some terrific learning resources. So why didn’t I go with Insight 2?   Price.   I caught Metric AB on sale for only $39. 

Flux which is $399. Two features that stand out: it has a “spectrum waterfall” display that, while graphics intensive, gives you a tremendous amount of information in a gorgeous visual format.   Additionally, it functions as a stand-alone program so you can have it running continuously on a separate monitor. ill Gates recommends flux if you can afford it.

Room for Improvements

• I’d love to have it run stand-alone like Flux so I can keep it open in another window. Because Metric AB runs as a VST on your master track, whenever you select another track your display disappears.
• The manual is minimalistic.
• No spectrum waterfall like Flux

Referencing tracks is critically important, and Metric AB is a fantastic referencing plugin. It’s a good value even at full price $199, but on sale for $39 it’s a steal.  There’s a 14 day free trail, so give it a shot. Watch for a sale and buy it immediately; in the meantime consider Voxango Span or iZotope Insight 2 if you’re a student or educator. 

Shoutout to Baphometrix for originally recommending Metric AB!

What are your must-have mixing or referencing plugins?