A free loudness matching plugin. Stop buying the louder one.
Parity measures the level going into your processing and the level coming out, then holds them the same. When you flip an EQ, compressor or limiter on and off, you hear what it changed, not how much louder it got.
Why louder always wins
Listeners tend to prefer the louder of two versions, even when nothing else changed. Push anything up 1 dB and it sounds fuller, brighter and punchier. That is one of the oldest traps in mixing: a plugin that adds gain looks like it is improving the sound, when part of what you are hearing is just the volume.
The fix is to compare at the same loudness. That is the whole job of Parity.
What Parity does
Parity measures loudness the way streaming services do, in K-weighted LUFS, and trims the output to match the input, up to 12 dB either way. A MATCHED light turns on when the two are within 0.3 dB, so you know the comparison is fair.
With the matching turned off, the audio goes through untouched, bit for bit. You can always hear the plain difference too.
How to set it up
- Put one Parity first in the chain and set it to SOURCE. It listens to the signal before your processing.
- Put another Parity last in the chain and set it to TARGET. It matches the output to what SOURCE measured.
- Put both in the same GROUP. There are eight groups, so you can run more than one chain.
- Bypass your processing with one key. The loudness stays matched, so what you hear is what the processing changed.
How accurate is it?
A test tone at -3.01 LUFS reads -3.01 at 44.1, 48 and 96 kHz. The MATCHED light uses a 0.3 dB window.
What it is not
Parity is not a reference-track player. It matches loudness; you pair it with whatever you use to switch between a chain on and off, or between two plugins. It also needs SOURCE and TARGET in the same host process: a host that runs each plugin in its own sandbox will not link them.
When it is worth using
Any time you are deciding whether a change is better: an EQ move, a compressor setting, a clipper or limiter on the master, two plugins doing the same job. Match the loudness first, then listen. If you still like it, it is a real improvement.
Questions
Is Parity really free?
Yes. Parity is a free download for Mac and Windows. You enter your email once on the Parity page and the download buttons appear. There is no license key, no trial and no subscription.
Which DAWs does it work in?
On Mac it comes as AU and VST3, so it loads in Logic Pro, GarageBand, Ableton Live, Reaper, FL Studio, Studio One and others. On Windows it is VST3, for FL Studio, Reaper, Ableton Live, Cubase, Studio One and Bitwig. Pro Tools (AAX) is not supported yet.
What does K-weighted LUFS mean?
LUFS is a loudness unit that follows how people hear, and K-weighting is the frequency weighting it uses. It is the measure streaming services use to normalise loudness.
Does it change the sound when matching is off?
No. With matching off, the audio goes through untouched, bit for bit.
What does it run on?
Mac: macOS 12 or newer, Apple Silicon and Intel. Windows: 10 and 11, 64-bit. The Mac installers are signed and notarized by Apple.
More free plugins for heavy music are on the free plugins page, and the Mix Notes show these tools at work.
Next step: when free is not enough
- Vantage: mastering that listens first (launch-week price until Nov 3).
- Bulkhead: a true-peak limiter with a loudness readout, $19.
- Anvil: lays a tuned sub under every kick, $12.
One-time prices, Mac and Windows, 14-day refund. See every paid plugin