Strange Subwoofer Measurement

[jrobbins50]

Bernt, a few weeks ago, as you were returning from your vacation, Mitch Barnett consulted with you during the course of helping me optimize my 5.1.2 main system. Over and over, the subwoofers measured as though they were 10 feet behind the mains, when in fact, the subs were in line with the mains.

At the time, you advised Mitch that this was okay and indeed, the frequency and step responses look great and sound great.

I am, however, trying to understand why this strange measurement consistently occurs and why it seems to make no difference to the fine outcome. Thanks. JCR

 

[kevinzoe]

Is it possible that your subs measured as though they were 10feet behind the mains when in fact they were in line with them due to the sub's inherent group delay?
I imagine that Bernt's software would time align things accordingly, not based on physical proximity of sub to main speaker....

 

[jrobbins50]

I’m not sure. All I know is that in the course of working with Mitch Barnett on optimizing my AL filters, the subs always measured not as Mitch expected. I also know that, in the end, Bernt said there was no problem and indeed, it is all time aligned. I was just hoping that Bernt might offer up a lesson for all of us. JCR

 

[jrobbins50]

Example attached. Front mains, subs, center and top height speakers are essentially all in a straight line. Note how the subs measure so far off the other speakers. JCR

 

[Omid]

Hi Jeffrey,

Does your subwoofer have an internal DSP? If it does it could introduce a significant delay.

 

[jrobbins50]

No, Omid, these are GoldenEar SuperSub XXLs that have crossover but no DSP and no polarity adjustments, either.

As noted above, outcome is not in question. See results attached. JCR

 

[Omid]

No, Omid, these are GoldenEar SuperSub XXLs that have crossover but no DSP and no polarity adjustments, either.

As noted above, outcome is not in question. See results attached. JCR

A bit hard to read but I think I see 7 step responses, where there should be 8. I think none of these step responses represent the subwoofer’s step response.
Can you zoom out and see if there’s another step response a bit later?