What happened to my room acoustics

I measured the spectrogram for my room at my MLP, and the FFT results are as follows:

- There is a roll-off before 20kHz.

- A dip is present around 12kHz.

- There is a noticeable boost between 50Hz and 1.5kHz.

- The bass rolls off around 33Hz at -3dB, consistent with the factory rating.

Comparing these measurements to the Burchardt measurements, there are some differences:

- It doesn’t exhibit a roll-off before 20kHz.

- The dip is around 15kHz.

- The boost between 50Hz and 1.5kHz is not as pronounced as in my room.

I’m curious about what might be happening with my room acoustics. If a fix is possible, what would it entail?

Spectrogram from my zoom


My room / speakers setup


Measurements from Burchardt


Your room doesn't look that bad to me, many are much worse. Of interest is that you mapped out the "golden triangle" and then didn't adhere to it. As others have suggested, your listening chair is too far away from your speakers. I suggest you pull your speakers another foot into the room and move your seating position at least two feet farther into the room. Try listening to music instead of measurements.

A few comments:

Yes, move the seat forward. You’re probably hearing a lot from the rear wall you could eliminate by moving forward. My speakers are 8 feet apart and I sit 10 feet away. My back wall is another 9 feet behind me. Worth a try.

Did I miss comments about ceiling height? Some of the worst reflections come from floor or ceiling. They may be interfering. It's very helpful to measure impulse responses to see how the reflections are, or you won’t get a handle on imaging and soundstage.

Get those as many reflections between 4 and 12 ms down below -20db if you can. Viz.

measurement artifact - sweep length | Audio Science Review (ASR) Forum

- There is a roll-off before 20kHz.
- A dip is present around 12kHz.

COMMENT: These are very high and likely won’t matter much. (In my view.)
- There is a noticeable boost between 50Hz and 1.5kHz.

COMMENT: Much more important.



I agree with others, your listening spot is too far back. If your speakers are 9’ apart, try moving your listening spot to 8’-10’ a few inches at a time.

All the best.


In my opinion:

 "There is a roll-off before 20kHz.."  This is the shortest wavelengths being absorbed by surfaces in the room. 

"A dip is present around 12kHz.."  There will be a on-axis cancellation dip in the response with a round horn or round waveguide, centered on the frequency where the mouth reflection arrives 180 degrees out-of-phase a the listening position.   The center frequency of this dip changes with listening distance or microphone distance.  Off-axis the arrival time of the horn mouth reflection is smeared, and the cancellation dippage is correspondingly reduced. 

"There is a noticeable boost between 50Hz and 1.5kHz."  The midwoofer's pattern is wider than the waveguide's pattern below the crossover frequency resulting in more in-room energy below the crossover frequency.


Thank you all for the advice. It appears that the consensus here is that I am sitting too far from the speakers. I've adjusted the seating position, bringing it closer to the speaker plane (11 ft), with the speakers now placed 9 ft apart. My room has a 10 ft high ceiling. At the new MLP, I measured the spectrogram again on both channels, both together and separately. The FFT results are as follows: The high-frequency dip has shifted to a slightly lower frequency and appears to be more pronounced. The left and right channels exhibit similar profiles.  On paper, it appears that sitting closer is not resulting in improved sonic performance in my room.  Basically, I agree with @audiokinesis who commented on the in-room energy below crossover frequency (=1.8khz).  I probably need a lot of panels on the sides, which may not receive WAF certification.