Unexplained behavior when coming to measure Lt+Rt

[ErLan]

Hello,
I am trying to tune my 2.1 setup.
In order to align low frequencies phase I intended to run a Lt + Rt measurement and Sub (saparately) and use the alignment tool to set delays.
Nevertheless, when coming to measure (setting L+R) as output, the output signal is coming inExlusive mode from my sub.
Any idea what may be the roit cause for that?

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My set up:
PC equipped with EQ apo >> sound card ASUS xonar U5 (5.1 outputs) >> amplifier + (active) sub

REW: 5.30 beta2, using the java interface.
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Thanks!

 

[John Mulcahy]

Perhaps the soundcard is configured to apply bass management. Shouldn't be an issue for what you are trying to do though, just turn the sub off to measure the mains and vice versa. Best measuring the channels separately rather than L+R.

 

[ErLan]

Thanks Paul,

I have only 1 sub, and (unfortunately) untreated room so there is some phase difference between L & R. That is why I thought of using the combimed L+R for that.
Having that being said, will the 'mathrmatical operation of 'trace arithmetic > A+B (in my case L+R) is accurate for that?