Help with Measuring My Room without Blowing up Speakers

Touch The Universe said:

I'm trying to measure my room. It says to match 75db but something isn't right. The audio is maxed out on my computer and focusrite 2i2 and at max it's 65-70 db and it's very loud.

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If it's very loud then it isn't 65-70 dB! If you aren't using a USB mic with a calibration file including sensitivity REW has no way to know how to translate the data values from the mic into SPL figures. You tell REW how to do that through the SPL calibration process. Best also read the Check levels process, paying particular attention to the first few sentences:

REW measurements are usually made at a level of about 75 dB SPL. This is not very loud, it is the same level aimed at by most receivers to adjust speaker trims. Using very loud test signals is likely to damage your speakers and your ears. Do not use test signal levels any higher than you would be comfortable listening to for long periods.

The UMIK may not have been selected as the input device and input in your first measurement and there is no input selection in the zoom.mdat file, in both those cases REW can't apply the sensitivity info. The UMIK was correctly selected in the 4.mdat and 5.mdat files you posted so those were actual levels. Note that if you unplug the UMIK while REW is running the input selection will be lost.

You have also loaded the mic calibration file as a soundcard calibration file. That is wrong, and REW gives you a message to tell you so. Clear the soundcard calibration file in the REW soundcard preferences. There is a guide that covers using the UMIK in the downloads area, worth looking at.

You have a very wide graph range (150 - 200 dB depending on the graph), so things look much flatter than they are. Use the Limits button at the top right of the graph to set a range of 60 dB - have a look at Matt's video for more on that:


Flat in-room responses do not exist, you may get flattish curves by applying a lot of smoothing or setting a very wide SPL range but every room has peaks and troughs, particularly in the low end. Here is your response with a 60 dB range and minimal smoothing (best for seeing what the low end is doing):


There is a very big peak at 50 Hz, which is probably mostly due to positioning of the sub and/or your listening position. The REW room simulator can help with getting an idea of how different positions will look if your room is rectangular. The sub is also well above the rest of the response so needs bringing more into line by reducing its level. Some gentle downward slope from low frequencies to high is normal for listening position measurements, but yours is more of a mountainside just now

Looking a lot better! A parametric filter would tackle that 72 Hz peak without much drama. Those ripples at the top end suggest you had both speakers playing and they are at slightly different distances from the mic position. You'll see a smoother top end measuring each speaker on its own.

For treatment best looking online at the options, GIK Acoustics (for example) have explanatory material alongside their offerings that should help figure out what might help.

Not really, I'm no expert in treatment options.