Multi-channel time allignment

[FidelioX]

Hi guys,
Im trying to find out the best method to time allign all my speakers to the reference one (in my case front L).
I've seen some videos on youtube but ...are dated and I've some doubts.

My testing array is a 4.1 (two front speakers , two surround and one sub).
I have a Denon X4700 receiver.

The attached maesures are taken with the default delay settings on the receiver ... If I remeber well are 3.60 meters for front and sub speakers and 3.00 meterso for surround.

My fist question is related to the reference L measure here ...

Why this measure (that is the reference) has a delay value?? It shouldn't be ZERO ?

The other question is related to the measure done for the sub ....

If I still perform a reading from 10 to 20000hz the results is like this...

So REW is telling me that I've to set a delay of 2,666 ms.

If I perform a restricted measure (10 -250hz) the delay time is different ...

something around 1,67 ms.

Why the delay changes related to the measuring range?
What is the right method to measure the sub related to other loud spaekers measurements??

Thank you so much

 

[John Mulcahy]

The timing signal is a 5 kHz to 20 kHz sweep, it may have slightly different timing to the overall response of the reference speaker with a full range sweep.

To align the subwoofer best using the Alignment tool to find a good phase alignment through the crossover region.

 

[FidelioX]

Thank you John for your feedback!
Ok, I will use a sweep 5k to 20k to time align all the loud spaekers the my reference one (L). Do you have some suggested resolution for this kind of sweep?

But, I'm curious ....when I'll redo the measurements as you suggested ....the delay reported by REW for my reference speaker (L) will be zero?
Or REW will still report some small delay also for the refernce speaker?
If yes what is the reason for it?

thanks a lot.

 

[socbutter]

I've found these two Youtube videos to be quite helpful. Unfortunately, I'm unable to post links. Thank you, OCA.

Optimal Subwoofer Alignment with Cross Correlation​

Supreme Audyssey Calibration by OCA​

 

[John Mulcahy]

Ok, I will use a sweep 5k to 20k to time align all the loud spaekers the my reference one (L).

No, do not do that, use the normal full range sweeps. I was only explaining why the reference channel can have a non-zero delay. Speakers do not have perfectly flat group delay so there will be some dependence on the frequency span of the signal.