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Need help with room eq

thanhh

Member
Joined
Sep 17, 2019
Messages
38
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25
Hi,
I’ve just done my speakers eq using REW and rePhase. The filters then being run by brutefir on Rapserry pi 4 Volumio. When using Volumio to check the eq results, the left and right speakers seem right where they need to be. But when I measure both of them together, I have a huge dip around 4.5KHz and 15KHz. I’m not sure what caused it or how to fix them. Could anyone help please
BC5D3B9E-0787-4585-B07D-EAA4E099ECC9.jpeg

This happened to both of my speakers, a pair of Maggies MG12/QR and a pair of Kef Q950. Both speakers are 0.9m from front wall, my listening seat is 2m from the center of 2 speakers, speakers are 1.7m apart.
The measurements are of the Maggies.
 

Pio2001

Senior Member
Joined
May 15, 2018
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507
Location
Neuville-sur-Saône, France
Hi thanhh,
I see two possibilities : something was very close to your microphone during the last measurement : a surface 1.5 cm from the tip of the microphone can cause these dips in the frequency response. The solution : hold the micro far from any surface during the measurement.

Other possibility : you have a very dead acoustic (or your speakers are very directive), and the stereo measurement was not made at the exact center of the two speakers. Being a few centimeters closer to one speaker than to the other can produce such dips in an anechoic room.

To investigate, use REW generator to play a Noise / Pink periodic / Full range, then click on RTA. In the parameters, choose Average = none, and click on the red button to start monitoring.
This way you can see the dips coming and going as you move your microphone.
 

QMuse

Major Contributor
Joined
Feb 20, 2020
Messages
3,124
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2,785
Hi,
I’ve just done my speakers eq using REW and rePhase. The filters then being run by brutefir on Rapserry pi 4 Volumio. When using Volumio to check the eq results, the left and right speakers seem right where they need to be. But when I measure both of them together, I have a huge dip around 4.5KHz and 15KHz. I’m not sure what caused it or how to fix them. Could anyone help please
View attachment 61548
This happened to both of my speakers, a pair of Maggies MG12/QR and a pair of Kef Q950. Both speakers are 0.9m from front wall, my listening seat is 2m from the center of 2 speakers, speakers are 1.7m apart.
The measurements are of the Maggies.

HF response is meaningless when both speakers response is measured with sine sweep, you should use moving microphone method with RTA pink noise, as shown in this video.

Btw, your L and R curves are looking pretty good but peaks at 48 and 102Hz should further be pushed down for app 4dB.
 
OP
thanhh

thanhh

Member
Joined
Sep 17, 2019
Messages
38
Likes
25
Thanks guys for wonderful advices, I did a quick RTA measurement using moving mic technique as showed above and confirmed that no dips visible at HF. Since this my 1st try at this, I will have to play around with filters to find what sounds best but so far I’m very happ with the results. Thanks again.
D4C1005F-E752-47CA-B3F7-DF7735B48CEF.jpeg

P.s. I have to use phone to take picture on the screen of my windows tablet since I’ve got no mouse or keyboard. So there’s no way I can navigate around Windows using just touch screen.
 
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