REW room correction on Mac: measure, generate filters, apply system-wide

updated September 28, 2026

Can you apply REW filters system-wide on a Mac? REW can measure a room and generate parametric EQ filters, but it does not itself apply them to all macOS audio. Reflect can import REW Generic filter exports and apply them system-wide on supported Macs. Other options include an AU host, a virtual audio route, or hardware DSP. See the system-wide EQ guide for the tradeoffs.

Room EQ Wizard is the free reference tool for room measurement, and it runs fine on macOS. The workflow has three stages: measure, generate filters, apply them. On a Mac, stage three needs a separate playback path because macOS has no Equalizer APO. This guide covers all three stages and the Mac-specific options.

Step 1: Measure your room with REW

1. Get a microphone. The standard is the miniDSP UMIK-1, a calibrated USB mic that macOS treats as a normal audio device. Download its calibration file from miniDSP and load it in REW under Preferences, Mic/Meter.
2. Set your devices. Choose the UMIK-1 as input and your DAC, interface or speakers as output. Java audio sometimes picks the wrong sample rate on macOS, so match REW to the device's rate in Audio MIDI Setup.
3. Put the mic at your listening spot. Ear height, where your head normally is. Pointing up with the 90 degree calibration file, or at the speakers with the 0 degree file.
4. Run the sweep. Open Measure, check levels with the SPL meter first, then sweep each speaker. Keep the room quiet.

Apply 1/12 or 1/24 octave smoothing and read the graph. A typical desk setup shows one or two big peaks between 40 and 150 Hz. That is your boom, now visible.

Step 2: Generate EQ filters

1. Open the EQ window from your measurement.
2. Set the equalizer type to Generic. That produces standard parametric filters (frequency, gain, Q) that any host can reproduce.
3. Limit the match range to roughly 20 to 200 Hz. Full-range auto-EQ chases wiggles that shift with every head movement.
4. Click Match response to target, then review the filters. Keep the cuts, delete or limit the boosts. Boosting into a null does not work, it only eats headroom.
5. Export via File, Export, Filter settings as text.

Step 3: Apply the filters system-wide on macOS

REW stops here. It measures and calculates, it does not process playback. On Windows you would paste the filters into Equalizer APO and be done. macOS has nothing like it, so pick a route:

Option A: AU host plus parametric EQ plugin

SoundSource (paid) or eqMac (free) can put Audio Unit plugins on system audio. Load a parametric EQ and retype every filter's frequency, gain and Q by hand. Works well. The costs: the host app, the retyping after every re-measure, and one more thing living in your audio path.

Option B: hardware DSP

A miniDSP box between Mac and speakers loads REW filters directly and corrects every source connected through that hardware, including sources outside your Mac. The tradeoff is an extra box, cables, and its own configuration software.

Option C: import into Reflect

Reflect exists because of this exact gap. It reads REW's Generic filter export directly and applies it to all Mac audio through CoreAudio Process Taps. No virtual devices, no retyping, and a bypass toggle for A/B checks. It has its own guided measurement too, so a quick re-check does not need a REW session. Reflect corrects 20 to 200 Hz, which matches how REW filters for room correction should be generated anyway.

Verify: measure again with correction on

Whatever route you pick, sweep once more with correction active. The peaks you cut should sit flat within a couple of dB. If a cut did nothing, you probably cut a measurement artifact or you are sitting in a null. And if it measures right but sounds worse, you over-corrected above 200 Hz. See the room correction guide for what EQ can and cannot fix.