Surprisingly jagged response with EMM-6 and Scarlett 2i2

[John Shriver]

MacBook Air, macOS Sonoma 14.5, REW 5.35.1, Scarlett 2i2 (2nd Gen, not latest), Dayton EMM-6 microphone.
I calibrated the 2i2 using loopback from line on back to input on front with tip-sleeve phone jack cable. Used the calibration file from Dayton.
Used GenRad 3561 sound level meter on C-slow to calibrate 75 dB level.
Measuring at either 1 or 3 meters, lots of narrow dips in frequency response above 1 kHz. Is this typical, or have I somehow messed up the timing between output and input?

 

[John Mulcahy]

Yes, that's typical, caused by reflections from the room's surfaces. Smoothing cleans it up.

 

[John Shriver]

OK, even 1/48 smoothing makes it much more reasonable. Walls and ceiling of 10x12 foot room are hard plaster, dense rug on floor.