> ## Content Index > Fetch the complete content index at: https://soundforgepro.com/llms.txt > Use this file to discover other available public pages before exploring further. # Best Free Metering Plugins: 8 Tools for Loudness, Spectrum and Phase - URL: https://soundforgepro.com/free-metering-plugins/ - Published: 2026-09-28T12:52:52.000Z - Updated: 2026-10-17T07:06:28.000Z - Description: Eight free audio metering plugins matched to loudness, true peak, spectrum, masking, dynamics, stereo phase and quick level checks. - Author: Erick Finn - Tags: Audio Tools **If you want one free meter that covers the most everyday checks, start with Voxengo SPAN. Add Youlean Loudness Meter when delivery loudness and true peak are the question, TDR Prism when you need to see masking or compare a reference, and Voxengo Correlometer when stereo phase is the concern.** These tools are not eight versions of the same plugin. Each answers a different monitoring question, and choosing by that question is more useful than filling the master bus with overlapping graphs. CHOOSE THE QUESTION FIRST **Loudness and true peak**Youlean Loudness MeterClear starting point for LUFS-oriented delivery checks **Broad spectrum and levels**Voxengo SPANOne flexible view for frequency, level and correlation **Masking and references**TDR PrismPerceptual weighting and comparison between sources **Stereo phase risk**Voxengo CorrelometerMultiband correlation and mono-compatibility diagnosis ## Free metering plugins compared by diagnostic task | Question | Free plugin | What it shows | Current compatibility note | Do not expect it to | | --------------------------------------------------------------------------- | ----------------------------- | ------------------------------------------------------------------------------------------------------------ | --------------------------------------------------------------------------------------- | -------------------------------------------------------------------------- | | **How loud is the program, and where are true peaks?** | Youlean Loudness Meter | Free integrated loudness, loudness range, true peak, PLR and DR readouts, with loudness and true-peak graphs | Windows and macOS; application, VST2, VST3, AU and AAX | Decide the correct delivery target without a platform specification | | **Where is the spectral energy, and are levels or correlation suspicious?** | Voxengo SPAN | FFT spectrum, level statistics, EBU R128/K-system views, true-peak clipping and correlation | 64-bit Windows and macOS; VST/VST3/AU/AAX families vary by OS | Tell you whether a tonal choice is musically right | | **Which frequencies may be masked, and how does a reference differ?** | TDR Prism | Perceptual spectrum, auditory masking and source comparison | Windows, macOS and Linux; available formats vary by OS | Replace listening-level matching or arrangement decisions | | **How do RMS, crest factor, loudness and dialog measurements relate?** | TBProAudio dpMeter5 | RMS, EBU R 128, dialog-gated, true-peak, crest and loudness-range views | Windows and macOS; current developer downloads list common plugin formats | Run DIAL measurements at sample rates other than 44.1 or 48 kHz | | **Do I need a spectrum analyzer with detailed display controls?** | MeldaProduction MAnalyzer | Spectrum, normalization, smoothing, prefiltering, deharmonization and integrated level meters | Included in the current MFreeFXBundle | Provide every paid resize, preset and sonogram feature in the free tier | | **Can I get a simpler real-time spectrum display?** | Blue Cat FreqAnalyst | Mono/stereo spectrum, smoothing, zoom and threshold controls | Windows and macOS in VST/VST3/AU/AAX families | Include the Pro edition’s curve storage, precision tools or 3D spectrogram | | **Can I check level, loudness and M/S without a large analysis suite?** | HOFA 4U Meter, Fader & MS-Pan | Peak, hold, EBU, loudness range, M/S and file analysis | PC and Mac; verify the current installer because the page retains legacy format wording | Replace a dedicated spectrum or phase-analysis tool | | **Is the stereo problem limited to part of the spectrum?** | Voxengo Correlometer | Correlation across 4–64 bands, phase-risk cues and sidechain comparison | 64-bit Windows and macOS; VST/VST3/AU/AAX families vary by OS | Prove that width, polarity or timing is correct by itself | **How I made the shortlist** The recommendations below group tools by the measurement tasks described in their product pages and documentation; they are not an installation, benchmark or accuracy ranking. ## Loudness, spectrum, masking and correlation answer different questions A meter becomes useful only after you can finish the sentence: “I need to know whether…” A loudness meter can show program loudness and true peak, but it cannot explain a harsh upper midrange. A spectrum analyzer can show where energy accumulates, but it cannot decide whether that energy belongs there. A [correlation meter](https://soundforgepro.com/phase-correlation-meter/) can warn about possible mono loss, but a positive reading is not a quality certificate. ![Decision map matching six audio questions with loudness, spectrum, masking, dynamics, stereo correlation and level meters](https://storage.ghost.io/c/af/4b/af4b05d4-2e0b-4edc-8378-1e2a62fecc70/content/images/2026/09/inline-metering-question-map.webp) Choose the meter from the question: delivery level, tonal balance, masking, dynamics, stereo phase or a quick channel check. DELIVERY ### Loudness and true peak Use these readings when a broadcaster, podcast host or other destination gives a measurable delivery specification. If you need a quick browser check before opening a DAW, the [SoundForgePro LUFS meter](https://soundforgepro.com/lufs-meter/) covers that separate task. TONAL BALANCE ### Spectrum Use a spectrum view to locate persistent low-end buildup, narrow resonances or missing regions. The [browser audio spectrum analyzer](https://soundforgepro.com/audio-spectrum-analyzer/) explains the FFT view without turning the graph into an automatic EQ instruction. MASKING ### Perceptual comparison Use masking and reference overlays to ask whether one source hides another or whether two spectra differ. Match playback level before treating a brighter or louder reference as better. DYNAMICS ### RMS and crest factor Use level history and crest factor to describe the relationship between average and peak behavior. They are clues about dynamics, not targets that every genre must share. STEREO ### Correlation and mono compatibility Use correlation to find frequency regions that may cancel when summed. The full [mono-compatibility and phase-correlation guide](https://soundforgepro.com/mono-compatibility-phase-correlation/) owns the corrective workflow. CHANNEL CHECK ### Peak, hold and M/S Use compact meters for gain staging, mid/side balance and fast file checks when a full spectral display would add noise rather than information. ## 1\. Youlean Loudness Meter: start here for loudness and true peak Youlean is the clearest first addition when the destination gives you a loudness or true-peak requirement. The [current Youlean product page](https://youlean.co/youlean-loudness-meter/) describes loudness, loudness range, dynamics and true-peak measurement and lists Windows and macOS application, VST2, VST3, AU and AAX options. The free edition includes integrated loudness, true peak, loudness range, PLR and DR readouts, plus loudness and true-peak graphs. It supports mono, stereo and 5.1 audio and does not expire. I would start there for delivery checks. Pro adds streaming presets, a dynamics graph, PDF/PNG/SVG exports, custom presets, A/B states and drag-and-drop analysis; you do not need those extras just to read integrated loudness and true peak. **Choose it when:**a delivery requirement is written in LUFS or true peak and you want a dedicated view rather than a multipurpose analyzer.**Do not expect it to:**choose the correct target for you. Streaming and broadcast requirements change by destination; use the current specification, not a remembered universal number. ## 2\. Voxengo SPAN: the most useful general-purpose starting point SPAN is my default recommendation when someone asks for “a free meter” but has not yet narrowed the problem. According to the [official SPAN page](https://www.voxengo.com/product/span/), it combines an FFT spectrum analyzer with stereo, mono and mid-side views, level statistics, true-peak clipping detection, EBU R128/K-system metering and stereo correlation. That breadth makes it a sensible first diagnostic panel. The advantage is consolidation: one plugin can reveal a low-frequency concentration, a clipping concern and a suspicious correlation reading without opening three windows. The danger is assuming one window gives one answer. Read each section independently and follow the clue with the relevant listening or mono check. **Choose it when:**you want one flexible analyzer for spectrum, levels and a quick stereo check across common 64-bit Windows or macOS hosts.**Do not expect it to:**decide that a spectrum is balanced because it follows a preferred slope, or that a correlation value makes the mix safe in every playback system. ## 3\. TDR Prism: best for masking and reference comparison Prism earns its place because it asks a more useful question than “what does the spectrum look like?” The [TDR Prism documentation](https://www.tokyodawn.net/tdr-prism/) describes perceptual weighting, human auditory filters, real-time masking indication and comparison between regular inputs, sidechains, audio files and other Prism instances. That makes it especially relevant when two sources compete or a reference seems different but the cause is unclear. Reference comparison still needs level discipline. A louder reference often appears fuller and clearer before any spectral judgment begins. Prism can show the difference; it cannot remove the bias created by mismatched playback level or tell you whether an arrangement should leave more space. **Choose it when:**you need to compare sources, inspect likely masking or view the spectrum through a perceptual model.**Do not expect it to:**solve masking automatically. The useful response may be arrangement, timing, level, panning or sound choice rather than EQ. ## 4\. TBProAudio dpMeter5: best for dynamics and dialog-oriented readings dpMeter5 is the stronger choice when the question includes RMS, crest factor or dialog-gated measurements rather than only integrated loudness. The [current dpMeter product page](https://www.tbproaudio.de/products/dpmeter) lists RMS, EBU R 128 and DIAL modes, along with integrated, momentary, peak, true-peak, loudness-range and crest readings. For dialog work, check the session sample rate first: the [dpMeter5 manual limits DIAL measurements to 44.1 and 48 kHz](https://www.tbproaudio.de/assets/content/manuals/dpMeter5%20manual.pdf). This restriction applies to DIAL mode, not to every measurement in the plugin. Choose a dialog-gated reading only when your delivery requirement calls for it; a music mix and a dialogue program may need different measurements. **Choose it when:**you need several level and dynamics views in one plugin, especially RMS, crest factor, loudness range or dialog-gated readings.**Do not expect it to:**provide DIAL measurements outside the documented 44.1 or 48 kHz sample rates. ## 5\. MeldaProduction MAnalyzer: detailed spectrum work with a free-tier caveat MAnalyzer is a broad spectral tool for readers who want more than a simple curve. The [official MAnalyzer page](https://www.meldaproduction.com/MAnalyzer) documents smoothing, normalization, super-resolution, prefiltering and deharmonization, along with spectrum analysis and integrated peak and loudness meters. Sonogram access requires the paid MFreeFXBundle upgrade. Two limits matter. First, Melda’s page still describes its loudness meter as EBU R128 and ITU-R BS.1770-3 compliant, so that is the revision to report. Second, the [MFreeFXBundle comparison](https://www.meldaproduction.com/MFreeFXBundle) says paid activation adds resizing, preset management and sonogram access in analyzers and equalizers. Do not assume the product headline means every displayed feature is available without the upgrade. **Choose it when:**you want configurable spectrum analysis and the rest of the free Melda bundle is useful to your workflow.**Do not expect it to:**include every interface, preset or sonogram feature in the free tier, or to document a newer loudness revision than BS.1770-3. ## 6\. Blue Cat FreqAnalyst: a simpler real-time spectrum view FreqAnalyst fits the opposite preference: a focused spectrum display without the broader metering stack. Blue Cat describes the [free FreqAnalyst](https://www.bluecataudio.com/Products/Product%5FFreqAnalyst/) as a mono and stereo real-time spectrum analyzer with control over frequency transformation, smoothing, zoom and thresholds, available for Mac and Windows in common plugin formats. The same page clearly separates the Pro edition. Saving and restoring curves, precise measurement tools, a 3D spectrogram and related advanced functions are not safe claims for the freeware version. If your question is simply “where is the energy?”, that limitation may be useful: fewer controls can make the first diagnosis faster. **Choose it when:**you want a straightforward spectrum monitor and do not need masking, multitrack comparison or a dense loudness panel.**Do not expect it to:**include the Pro edition’s curve storage, precision measurement or 3D spectrogram features. ## 7\. HOFA 4U Meter, Fader & MS-Pan: quick level and M/S checks HOFA’s 4U utility is useful when you want a compact channel tool rather than another large graph. The [current HOFA freeware page](https://hofa-plugins.de/en/freeware-en/) describes peak and hold metering, EBU readings, loudness range, M/S encode/decode, stereo/mono switching and drag-and-drop file analysis. The page lists Audio Unit, VST, VST3 and AAX formats and retains both 32- and 64-bit DAW wording. Treat that as a reason to check the actual installer for your current OS and host before planning a session around it. The feature fit is clear; the compatibility sentence should stay cautious. **Choose it when:**you need compact level, loudness and M/S controls for fast channel or file checks.**Do not expect it to:**replace a detailed spectrum analyzer or a dedicated multiband correlation display. ## 8\. Voxengo Correlometer: best for multiband stereo correlation Correlometer is the specialist in this group. The [official Correlometer page](https://www.voxengo.com/product/correlometer/) documents correlation metering across 4 to 64 bands, phase-issue detection, mono-compatibility checking and sidechain support. A broadband meter may look acceptable while a narrower frequency region cancels; the multiband view is designed to expose that distinction. Correlation remains a clue, not a verdict. Negative or unstable bands deserve a mono sum and a routing check, but the display does not tell you whether the cause is an intended stereo effect, a polarity error, a timing offset or a harmless local feature. Diagnose the cause before narrowing the entire mix. **Choose it when:**you suspect that stereo cancellation is concentrated in a frequency range or need to compare phase behavior between signals.**Do not expect it to:**prove that a mix is correct, or to replace a real mono playback check. ## What the loudness standards do—and do not—tell you [ITU-R BS.1770-5](https://www.itu.int/rec/R-REC-BS.1770-5-202311-I/en) defines algorithms for measuring program loudness and true-peak audio level. [EBU R 128-2023](https://tech.ebu.ch/docs/r/r128.pdf) uses program loudness for broadcast normalization, maximum true peak for the upper technical limit, and loudness range plus momentary and short-term measures to further characterize a program. Those documents explain the measurement framework; they do not create one universal target for music, podcasts, broadcast and every streaming platform. Use the destination’s current rules. SoundForgePro keeps the changing delivery details in the separate [streaming loudness standards guide](https://soundforgepro.com/streaming-loudness-standards/) and [podcast loudness guide](https://soundforgepro.com/podcast-loudness-standard/). If you are working specifically inside Sound Forge, the [Sound Forge loudness-meter walkthrough](https://soundforgepro.com/sound-forge-loudness-meters/) covers that software-specific path. ## A practical two-meter workflow For a delivery check, establish the destination’s current loudness and true-peak requirements before choosing a meter or changing the audio. A preset is a convenience, not a substitute for those requirements. 1. **Name the failure you are checking.**Clipping, delivery loudness, tonal buildup, masking and mono loss are different failures. 2. **Choose one primary meter.**Use Youlean or dpMeter5 for delivery and dynamics, SPAN or FreqAnalyst for spectrum, Prism for masking, or Correlometer for phase. 3. **Add one secondary view only when it changes the decision.**For example, pair a loudness meter with SPAN, or Prism with Correlometer. Avoid three spectrum analyzers showing the same clue. 4. **Confirm the graph with an audible check.**Level-match references, sum to mono when phase is the issue, and bypass processing before accepting the meter’s implication. 5. **Verify the final delivery readings.**For delivery work, compare the final readings with the requirements you established at the start. ## Which free meter should you download? **You want one broad starting tool** Choose **Voxengo SPAN**. It covers spectrum, levels, true-peak clipping and a quick correlation view without forcing you into a single delivery workflow. **You have a defined LUFS or true-peak requirement** Choose **Youlean Loudness Meter**. The free edition covers integrated loudness, loudness range and true peak. Use your destination specification to set the target; streaming presets and export reports are Pro extras. **You need RMS, crest factor or dialog-gated views** Choose **TBProAudio dpMeter5**. Choose the view required for your material; DIAL measurements require a 44.1 or 48 kHz session. **You are comparing a mix with a reference or hunting masking** Choose **TDR Prism**. Level-match first so the comparison answers a spectral question rather than a loudness bias. **You want a simple spectrum display** Choose **Blue Cat FreqAnalyst**. Choose **MAnalyzer** when you need a more configurable tool and accept the free-tier limits. **You are troubleshooting stereo cancellation** Choose **Voxengo Correlometer**. Follow suspicious bands with mono listening and routing checks instead of treating the graph as a pass/fail light. **You need quick channel, EBU or M/S checks** Choose **HOFA 4U Meter, Fader & MS-Pan**, then verify that the current installer supports your OS and plugin host. The useful free-meter setup is usually smaller than the download list. Pick the question, choose one tool that answers it, and add a second meter only when it covers a different problem. That keeps the screen readable and makes every measurement lead to a decision.