One is a free measurement toolkit that rewards tinkering. The other is a paid, hands-off correction engine. The right pick depends on how much you want to learn.
If you’ve measured your room once, you already know the truth: the room does more damage to your sound than almost any gear upgrade can fix. REW and Dirac Live are the two names you’ll hear most for fixing it, but they’re very different tools solving the problem from opposite ends. For the wider landscape, see my room correction guide; this is the head-to-head.
REW is the gold standard for measuring a room, and it costs nothing. It runs on Windows, Mac, and Linux, takes detailed measurements with a calibrated mic (a UMIK-1 is the usual pick), and shows you frequency response, decay, distortion, everything.
The catch: REW corrects nothing automatically. It uses IIR filters and hands you the data; you decide what to fix and apply it yourself (via a miniDSP, your AVR’s PEQ, convolution, etc.). For people who like to learn and tinker, that flexibility is the whole appeal. For people who just want better sound now, it’s homework.
Dirac Live flips the model. You take a guided set of (typically nine) measurements around your seat, and its algorithm generates a correction filter automatically. Crucially, it uses mixed-phase filtering, a blend of IIR and FIR, which can correct timing problems REW’s IIR-only approach can’t touch as cleanly.
The trade-offs: it costs around $349 (sometimes bundled into compatible gear), and it requires Dirac-compatible hardware, an AVR, processor, or miniDSP that can run the filter. You’re paying for automation and a more sophisticated algorithm, and giving up REW’s open-ended flexibility.
| If you… | Use |
|---|---|
| Want it free and love to learn/tinker | REW |
| Need full measurement flexibility | REW |
| Want hands-off, automatic correction | Dirac Live |
| Already own Dirac-compatible hardware | Dirac Live |
| Care about phase/timing correction | Dirac Live |
Honestly, they’re not mutually exclusive, plenty of people measure with REW (because it’s the best free analysis tool) and correct with Dirac (because it’s the easier engine). REW first to understand your room, Dirac to fix it without a degree.
REW isn’t the only free or low-cost path:
For the full menu from phone apps to Dirac Live ART, read the room correction guide.
HouseCurve turns an iPhone into a room-correction tool, measure your room, generate PEQ or FIR filters, and tame bass. Here's how it works and what Android users can do instead.
Spotify Lossless is here, but are you really hearing it? Learn what it is, why Bluetooth matters, settings to change, and DACs or headphones worth buying.
From free apps like HouseCurve to full Dirac Live ART setups, here's how audiophiles tune their listening rooms without an acoustic engineering degree.