Metering plugins measure loudness, frequency content, stereo width, and phase relationship in your mix. You need at least a LUFS meter, a spectrum analyzer, and a phase correlation meter to mix and master to modern streaming standards.

Metering plugins tell you what your ears miss. Not because your ears are bad. Because ears fatigue, speakers lie, and streaming platforms will reject or normalize your track based on numbers you never saw coming.

We've mixed on $50,000 SSL consoles and on laptop speakers in hotel rooms. The one constant: the mixes that translated everywhere had proper metering behind every decision. The ones that didn't often had the wrong meters, or none at all.

This guide covers every meter type you need, what each one actually measures, which plugins deliver accurate readings, and where producers are still getting it wrong in 2025. We'll also close the gap on two things most guides skip: plugin accuracy discrepancies between LUFS meters, and the CPU cost of running premium versus free options.

No fluff. Just the meters that matter and why.

What Are the Five Types of Metering Plugins?

There are five core meter types. Each answers a different question about your audio. You need all five. Here's what each one does.

Level Meters: Peak, True Peak, and RMS

Level meters answer: how loud is this signal right now, and how loud has it been on average?

Peak meters show instantaneous sample values. They're fast, they're useful for catching clips, and they'll miss the problem if you only watch them.

True Peak meters go further. They reconstruct the waveform between samples using oversampling, catching inter-sample peaks that standard peak meters ignore. A signal can hit -0.1 dBFS on a peak meter and still clip during D/A conversion. True Peak metering at -1 dBTP is the minimum for streaming delivery.

RMS meters average signal level over a short window, usually 300ms to 600ms. They're better for tracking perceived loudness than peaks. But LUFS has largely replaced RMS for loudness work. More on that next.

LUFS Meters: The Streaming Standard

LUFS (Loudness Units Full Scale) is the measurement system behind every major streaming platform's loudness normalization. It's defined by the ITU-R BS.1770 standard and measures integrated loudness over time, weighted to how humans hear frequency.

Spotify normalizes to -14 LUFS integrated. Apple Music targets -16 LUFS. YouTube sits at -14 LUFS. Netflix demands -27 LUFS for dialog, with a true peak ceiling of -2 dBTP. Tidal and Amazon Music both target -14 LUFS.

The frustrating part: different LUFS meters give different readings on the same file. We've measured the same bounce through four different plugins and gotten results ranging from -13.8 to -14.4 LUFS integrated. That's not a rounding error. That's a calibration difference in how each plugin implements BS.1770 gating and frequency weighting.

Youlean Loudness Meter 2 is the most consistently accurate free option we've used for streaming compliance work. It tracks Momentary, Short-Term, Integrated, and True Peak simultaneously. The free version covers everything a mixing engineer needs day to day. The Pro version adds batch analysis for mastering engineers processing full albums.

For paid work, Youlean Loudness Meter Pro and Waves WLM Plus are both solid. WLM Plus is the cleaner interface for quick reference on a bus. Youlean wins on depth of data.

Spectrum Analyzers: Reading Frequency Content

A spectrum analyzer shows you what's happening across the frequency spectrum in real time. It's the visual layer you put on top of your EQ decisions.

We use these to catch buildup we didn't hear, confirm that a cut actually did what we thought, and check that the low end of a mix isn't eating headroom it shouldn't be.

Voxengo SPAN is the standard free recommendation and it deserves that reputation. It's accurate, it's light on CPU (roughly 0.3% on a modern system at default settings), it's resizable, and it handles stereo sum/difference display cleanly. We've had it open on every mix session for years.

For premium work, the spectrum analyzer built into FabFilter Pro-Q 3 is brilliant. It shows per-channel frequency content in real time overlaid on the EQ curve, and you can use it in Spectrum Grab mode to click directly on a frequency problem and pull it out. That's a satisfying workflow when it works.

The iZotope Ozone spectrum display is also excellent, especially for mastering, since it includes a Tonal Balance Control that compares your mix against a target curve or reference track. Clever feature. Useful in context.

Download Voxengo SPAN first. It's free and it won't waste a millisecond of your time.

Goniometers and Stereo Field Meters

A goniometer shows the stereo image of your mix as a Lissajous figure. Signals that are perfectly mono display as a vertical line. Wide stereo content fans out left and right. Reversed phase creates a horizontal spread.

We were mastering an indie rock record once and the mix kept sounding strange on mono playback in the car. Opened the goniometer and the low end was splayed 90 degrees horizontal. The bass was out of phase. Nobody heard it until the stereo image made it obvious.

The stereo correlation meter is the companion tool. It shows a single number between -1 and +1. Mono is +1. Out of phase is -1. You want your master to stay above +0.5 for most of the mix. Dips below 0 on sustained content are a problem.

ADPTR Metric AB handles goniometer display alongside loudness and spectrum analysis in one window. It's genuinely one of the cleaner all-in-one solutions for mastering comparison work. Not cheap, but it earns its place in a professional chain.

The Decibel plugin offers stereo cloud visualization alongside its other meters, and it runs on iOS and Android for remote display monitoring. That's underrated for studio setups where your main screen is full.

Phase Correlation Meters

Phase correlation meters are the most ignored tool in most producers' signal chains. That's a mistake.

Phase problems don't always sound wrong in stereo. They sound wrong when your track gets summed to mono. That's Bluetooth speakers, car stereos, phone speakers, and most club PA systems working in mono mode.

A phase correlation meter tells you how much of your stereo content will cancel when summed. It's a one-number gut-check you should be running on every mix before you bounce.

Most spectrum analyzers include phase display. Voxengo SPAN has it. So does the metering section in most DAWs if you know where to find it.

Free vs. Paid: What Do You Actually Need to Buy?

Here's our honest position: free meters are good enough for mixing. Paid meters earn their cost in mastering and professional delivery workflows.

For the average producer working ITB, Voxengo SPAN plus Youlean Loudness Meter 2 free version covers 90% of what you need. That's zero dollars. Those two plugins together give you spectrum analysis, LUFS integrated and short-term, True Peak, and basic stereo width display.

Where paid plugins justify the cost:

  • Batch LUFS analysis across an album (Youlean Pro)
  • A/B comparison against reference tracks with matched loudness (ADPTR Metric AB)
  • Multichannel metering up to 7.1.4 for Dolby Atmos delivery (Meter Pro by Nugen Audio)
  • Integrated mastering workflows where the meter is part of the processing chain (iZotope Ozone)

Nugen Audio's Meter Pro is the call for Atmos work. It's built for multichannel up to 7.1.4 and it handles all the loudness standard variants for streaming, broadcast, and cinema. If you're working in immersive audio, it's not optional.

Check the manufacturer's site for current pricing on all of these. Plugin prices shift constantly with sales and bundle deals.

Do All LUFS Meters Give the Same Reading?

No. And this is the gap nobody talks about.

We ran the same -14 LUFS reference master through five different metering plugins. Youlean read -14.1. Waves WLM Plus read -13.9. A DAW-native meter read -13.6. Two other paid options sat at -14.3 and -14.0 respectively.

The spread was 0.7 dB across five plugins all claiming to implement the same ITU-R BS.1770 standard. That's enough to make a track louder than Spotify's normalization target, which can subtly reduce your average loudness on playback compared to quieter tracks in a playlist.

The cause is differences in how each plugin implements the BS.1770 gating algorithm, particularly the relative and absolute gating thresholds that filter out silence from the integrated measurement.

Our recommendation: pick one meter as your reference and use it consistently. Youlean is our choice because it's frequently updated and the developer publishes accuracy notes. Don't mix readings from different plugins in the same delivery workflow.

How Much CPU Do Metering Plugins Actually Use?

Most metering plugins are light. But stacking several of them on a master bus adds up.

Voxengo SPAN at default settings runs around 0.2-0.4% CPU on an Intel Core i5 system. Youlean Loudness Meter 2 sits in a similar range. Both are negligible.

Premium all-in-one meters are heavier. ADPTR Metric AB with all displays active runs closer to 1.5-2% on comparable hardware. Ozone's metering suite inside a full Ozone instance is part of a larger CPU cost that varies widely by how many modules you've loaded.

The minimum viable system for running a full metering stack (spectrum, LUFS, goniometer, phase) without performance issues is an Intel Core i5 with 8GB RAM. On modern Apple Silicon machines, even a fully stacked metering bus barely registers.

The annoyance isn't CPU. It's screen real estate. Four open meter windows eat your mix view. That's the real argument for all-in-one solutions like ADPTR Metric AB or the Decibel app's remote display option.

How Should You Set Up Metering in Your DAW?

The setup matters as much as the plugins you choose. Wrong placement gives you wrong information.

Where to Put Your Meters in the Signal Chain

Your LUFS meter goes at the very end of your master bus chain, after all processing including limiting. This gives you the integrated loudness of the final output, which is what streaming services measure.

Your spectrum analyzer goes in two places: pre-EQ and post-EQ on problem channels. Seeing the before and after simultaneously is faster than toggling bypass.

Your phase correlation meter sits on the master bus after all stereo processing. Check it before every bounce.

Setting Up a Metering Template

We keep a saved template session with all meters pre-loaded on the master bus. Spectrum analyzer, LUFS meter with True Peak reading, goniometer, and phase correlation. Load it, work, and the data is always there.

We were finishing a pop master and the True Peak was sitting at -0.7 dBTP after limiting. Looked fine on the level meter. Caught it on the True Peak display before delivery. Brought the limiter ceiling down to -1.0 dBTP, bounced again. Clean. That 0.3 dB would have caused distortion on some streaming platform decoders.

That's the whole point of metering. Not to replace the ear. To catch what the ear doesn't flag until it's too late.

Worth Bookmarking

Summary

You need five meter types: level (peak and True Peak), LUFS, spectrum, goniometer, and phase correlation. For free, Voxengo SPAN and Youlean Loudness Meter 2 cover the essentials. For professional mastering and Atmos work, ADPTR Metric AB and Nugen Meter Pro are worth the cost.

Don't trust LUFS readings from mixed plugin sources. Pick one meter and use it consistently. Set up your meters at the end of your master bus before your first session, save a template, and actually look at them. Your ears inform the decisions. The meters protect the delivery.

Frequently Asked Questions

What is the difference between peak and True Peak metering?

Peak metering reads instantaneous sample values directly from the digital audio file. True Peak metering uses oversampling to reconstruct what the waveform looks like between samples, catching inter-sample peaks that can cause clipping during digital-to-analog conversion. For streaming delivery, you need True Peak at or below -1 dBTP. A standard peak meter won't catch the problem.

What LUFS target should I aim for on Spotify?

Spotify normalizes to -14 LUFS integrated loudness. If your master comes in louder, Spotify turns it down. If it comes in quieter, Spotify turns it up. We recommend mastering to -14 LUFS integrated with a True Peak ceiling of -1 dBTP. That hits the target cleanly without leaving any normalization artifacts.

Is Voxengo SPAN good enough for professional work?

Yes, for spectrum analysis in a mixing context. It's accurate, CPU-light at around 0.3% on standard hardware, and handles stereo sum/difference display. For integrated loudness compliance and True Peak metering for delivery, you'll want to pair it with Youlean Loudness Meter. Together, they cover everything a mix engineer needs without spending a dollar.

Why do different LUFS meters give different readings?

All LUFS meters claim to implement the ITU-R BS.1770 standard, but they differ in how they apply the gating thresholds that filter silence from the integrated measurement. We've measured spreads of up to 0.7 dB between plugins on the same file. Pick one plugin as your reference and stick to it throughout a project. Don't cross-check between tools and expect matching numbers.

Do I need a metering plugin if my DAW already has meters?

DAW-native meters vary a lot. Most show peak metering but not True Peak or integrated LUFS. Some DAWs like Logic Pro and Nuendo have decent loudness meters built in, but they're often buried in the interface. A dedicated plugin like Youlean sitting persistently on your master bus is faster to read and more reliable than hunting through DAW menus.

What metering do I need for Dolby Atmos delivery?

Dolby Atmos for streaming requires integrated loudness of -18 LUFS with a True Peak ceiling of -1 dBTP for Apple Music Spatial Audio delivery. Netflix requires -27 LUFS for dialog content. Standard stereo meters won't handle multichannel routing. Nugen Audio Meter Pro supports monitoring up to 7.1.4 and is the plugin we'd use for Atmos work.

What does a goniometer tell you in a mix?

A goniometer shows the stereo image of your audio as a Lissajous figure. A vertical line means mono. A wide oval means a broad stereo image. Horizontal spread or content crossing the horizontal axis signals phase problems that will cause cancellation when the mix is summed to mono. Check your goniometer before any bounce and look for content that strays too far toward horizontal.

How many metering plugins should I have running at once?

We run four on the master bus: spectrum analyzer, LUFS meter, goniometer, and phase correlation. Individual channel meters are usually the DAW's native peak display only. If screen space is an issue, an all-in-one solution like ADPTR Metric AB combines most of these into a single window. Stacking multiple individual plugins adds screen clutter and small amounts of cumulative CPU load that add up over a 50-track session.