REW measurement interpreter
You measured your room.
Now find out what it means.
REW shows you the bumps. This tells you which ones matter, what causes them, and which no equaliser can fix.
Free. No account. Your measurement is analysed in your browser and never uploaded.
The usual route takes a week
- 1.Buy a measurement mic, install REW, work out how to run a sweep
- 2.End up with five graphs and no idea which bumps are a problem
- 3.Post "Need help interpreting results!" on a forum with three screenshots
- 4.Wait two days
- 5.Get four replies that contradict each other, two of which say to buy foam
What you get here instead
A diagnosis in plain language
“The +9.2 dB peak at 41 Hz is the first length mode of your room. Your seat sits at 94% of its pressure maximum.” Not a tutorial on how to read the graph yourself.
An ordered list of what to do
Free changes first, because moving a seat 40 cm usually beats anything you can buy. Traps before panels. EQ last, because it is fitted to the room as it is now.
Quantities and positions, not principles
Four corner traps, six panels, and the exact spot on each wall calculated from mirror geometry. Measured from the front wall, in metres or feet.
The honest part about EQ
Every problem is sorted into what EQ fixes, what it half-fixes, and what it can never touch. That third list is the one that saves you money.
The mistake almost everybody makes
A frequency response has peaks and dips, and the obvious move is to reach for a parametric EQ and flatten both. That works for the peaks. For a lot of the dips it does nothing at all, and it costs you headroom to find that out.
A resonance
A room mode is storing energy and letting it out slowly. Cut it and you feed the resonance less, so the level drops and the ringing shortens. EQ is a real fix here.
A cancellation
Sound bounced off a wall and came back inverted. Boosting raises the direct sound and the reflection by the same amount, so they still cancel. You get a hot amplifier and the same dip.
A long decay
The room keeps re-radiating energy after the note stops. A filter changes how much energy goes in, never how slowly it leaks out. Only absorption changes this.
They look identical on a frequency response graph. Telling them apart needs the room's dimensions and the distances between your speakers, your walls and your ears. That is exactly what this tool asks for, and exactly why it can answer the question. The long version is here
Three steps
Export from REW
File → Export → Export measurement as text, smoothing set to None. Add the RT60 export if you have one.
Enter the room
Three dimensions, where you sit, where the speakers are. Within 5 cm is close enough. Metres or feet.
Read the report
Score, annotated graph, every problem explained, an ordered fix list, and an EQ file that only touches what EQ can help.
Questions
- What file does it need?
- The plain-text export of a frequency response measurement. In REW: File → Export → Export measurement as text, with smoothing set to None. If you also export the RT60 data from the RT60 tab, the report can size an absorption package rather than only telling you where to put panels.
- Can it read .mdat files?
- No. The .mdat file is REW's own project format and is not documented. The text export holds the same measured data and takes about five seconds to produce.
- Why does it ask for room dimensions?
- Because without them a peak at 63 Hz is just a peak at 63 Hz. With them, it can tell you the peak is the first length mode of a 2.7 metre dimension, that your seat is sitting at 91% of its pressure maximum, and that moving 40 cm changes it more than any filter will.
- Is my measurement uploaded anywhere?
- No. Parsing and analysis both run in your browser. Nothing is sent to a server, which is also why the tool is free: there is nothing to pay for per report.
- How accurate are the treatment quantities?
- They are Sabine estimates from your room volume and measured decay time, using published absorption coefficients for 100 mm mineral wool. Expect them to be right to within a panel or two, which is enough to buy materials. The placement advice (corners, first reflection points) is exact geometry and does not depend on the estimate.
- Will this replace an acoustician?
- For a normal rectangular room with a normal stereo setup, it answers the same first questions an acoustician would, and it does it in seconds instead of a site visit. For an irregular room, a room that opens into another space, or a build-from-scratch project, hire someone.
Got a measurement sitting on your desktop?
Find out what it says