Cause of large upper-mid suckout from room that occurs with multiple speakers?

[mitchco]

@QMuse and @Willem make good suggestions. Place the mic 1ft to 3ft from the speaker with the mic at tweeter height pointing directly on axis to the tweeter. Take a measurement, post the result.
PS. Room eq will help with the dip between 100 and 200 Hz, not by boosting but by bringing the adjacent frequencies down...

EDIT: PS and how are you measuring your speakers? I.e. what is the signal path from REW onwards. Are you using a laptop with onboard soundcard for output?

 

[oursmagenta]

Hello,

Could it be due to a Speaker-Boundary Interference Response (SBIR) issue ?

http://arqen.com/acoustics-101/speaker-placement-boundary-interference/

 

[daftcombo]

http://arqen.com/acoustics-101/speaker-placement-boundary-interference/

I'd be interested to see @amirm 's calculations on this nice sheet for the Salon 2 ;-)

 

[dasdoing]

Hello,

Could it be due to a Speaker-Boundary Interference Response (SBIR) issue ?

http://arqen.com/acoustics-101/speaker-placement-boundary-interference/

no doubt....I have comparable suckout in this reagion over my mains. I don't have it with my sub which membrane is facing the front wall. I catualy cross at 200Hz because of this

 

[oursmagenta]

Almost like a text-book experiment ...
My left speaker was at the left corner of my room.
My right speaker was not (I have an open side).
Left speaker:
Right speaker:
Prediction for left speaker:
Prediction for right speaker:

 

[Shoaibexpert]

Hi, cam across this thread which was relevant to what I am facing now but for different set of frequencies. My suck out occurs at 3K, see pics. Any reasons for this and should this be corrected with REW...seems would be a huge boost in FR in that area or a huge cut in other FR to bring it in line.

 

[daftcombo]

Hi, cam across this thread which was relevant to what I am facing now but for different set of frequencies. My suck out occurs at 3K, see pics. Any reasons for this and should this be corrected with REW...seems would be a huge boost in FR in that area or a huge cut in other FR to bring it in line. View attachment 141893View attachment 141895

Can you window your measurements?

 

[eyes-on-you]

Same 3khz suckout to me.

Did you solve this?

What is the reason?

 

[FeddyLost]

If your measured responce is "flat" with any of speakers alone and have deep notch in midrange, it's most probably interference cancellation/diffraction issue on microphone. This effect is just consequence of small size of microphone. Compare wave lenth of notch with microphone size and you'll see.
In my experience with best alignment of mic according to acoustical axis and equal distances this notch is very deep and not so wide, when something is not precise, it widens.