Dynamic Range Test — Crest Factor
Measure dynamic range and crest factor with peak/RMS analysis in the style of classic TT meters. Indicative, not mastered proof. Free in your browser.
Protect your hearing. Start at a low volume. Never raise the volume to make a tone audible. Levels are shown in dBFS, relative to full scale — not SPL.
How it works
Official Bob Katz Pleasurize Music Foundation DR meter algorithm computed 100% locally via Web Audio API. No audio is ever recorded or uploaded.
Dynamic range is the contrast between the loudest transients and the sustained musical body of a recording. It gives music impact, punch, clarity, and emotional expression.
The Bob Katz / TT Dynamic Range Standard
Unlike simple uncalibrated peak-to-average measurements—which can be misleading due to silent intro pauses or single drum hits—the Pleasurize Music Foundation (PMF) algorithm measures true musical dynamics across standard 3.0-second intervals:
- The track is split into continuous 3.0-second non-overlapping blocks.
- The peak sample and RMS energy are calculated for each block.
- All blocks are sorted by loudness, and the loudest top 20% are isolated.
- The root-mean-square average of this top-20% selection is calculated ($\text{RMS}_{\text{top20}}$).
- The channel dynamic range is computed:
$$\text{DR} = 20 \log_{10}\left(\frac{\max(\text{Peak})}{\text{RMS}_{\text{top20}}}\right)$$
Dynamic Range Classifications
| DR Rating | Classification | Musical Character | Typical Genres |
|---|---|---|---|
| DR 14+ | Audiophile / Pristine | Enormous transients, deep contrast, breathability | Orchestral, Acoustic, Jazz, 1980s CD masters |
| DR 10 – DR 13 | Dynamic / Punchy | Clear punchy percussion, well-controlled dynamics | Classic Rock, Funk, High-res releases |
| DR 7 – DR 9 | Moderate Compression | Controlled dynamics for portable listening | Modern Pop, Modern Hip Hop, Radio mixes |
| DR 3 – DR 6 | Brickwall Limited | Flattened transients, constant loudness, fatigue | Loudness War CD releases, Aggressive EDM / Metal |
Drop any local audio file into this tool to inspect its dynamic profile and check whether your favorite tracks survived the Loudness War intact.
Frequently asked questions
What is the official DR (Dynamic Range) score?
The DR score is the standardized metric created by the Pleasurize Music Foundation and mastering engineer Bob Katz. It measures the crest factor between an audio track's overall peak level and the root-mean-square (RMS) energy of the loudest 20% of 3-second blocks, rounded to the nearest integer (e.g., DR14 for dynamic music vs. DR5 for brickwall limited pop).
What was the Loudness War?
Starting in the 1990s with digital peak limiters, record labels and mastering engineers competed to make CD releases louder by heavily compressing the dynamic peaks. While tracks sounded louder on first impression, squashing dynamic range from DR14 down to DR5 destroyed punch, transients, and emotional contrast, causing listener fatigue and distortion.
How do I interpret my track's DR rating?
DR12 and above indicates excellent dynamic range, typical of classical, jazz, and audiophile masterings with uncrushed drum transients. DR8 to DR11 is moderate, typical of balanced rock and pop. DR7 and below signifies heavy brickwall limiting with flatlined waveforms and diminished punch.
Is my audio uploaded or stored anywhere?
No. The entire decoding and forensic measurement takes place 100% in your browser's local Web Audio API context. Not a single byte of your audio file is ever uploaded, stored, or sent to any external server.