Need some help analyzing these measurements...

[TheHolyCannoli]

I started from scratch this afternoon. I've got about 30 measurements saved in REW with various crossovers and sub distance settings, with and without Audyssey activated. My goal is to find the best setup with Audyssey activated and a crossover at 60Hz. I'm not quite understanding why my 60Hz and 80Hz graphs are differing the way they do. I've taken multiple measurements at 60Hz with sub distances varying from 6ft, all the way up to 14ft, and it seems that 8.5ft is the lesser of all evils at 60Hz.

First, I measured the sub response with no filters or Audyssey activated, and without the mains connected. I don't recall the sub-distance set in the AVR, but I'm not sure if that makes a difference (although I believe it was set to 14ft in AVR).

Settings: No Audyssey, Sub alone, 120Hz crossover in AVR
https://lh6.googleusercontent.com/-ekulBdvJk3M/UwaZlrNR-bI/AAAAAAAAA4g/7r-BKzZeFoI/s800/sub%2520alone.jpg
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Then, using the Behringer Feedback Destroyer Pro DSP1124 parametric equalizer:
Target setting: flat curve (speaker type set to: None)
70dB target level
Filter Task: match range from 15-80Hz
https://lh3.googleusercontent.com/-xbAVcKbkWoA/UwaZlaIPltI/AAAAAAAAA4k/xmfjSltbEmM/s800/sub%2520after%2520eq.jpg
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Settings: No Audyssey, 80Hz crossover, sub distance 14ft
https://lh4.googleusercontent.com/-YxhHzSafRa8/UwaZk7WCSBI/AAAAAAAAA4Y/IxmPoTEfY2A/s800/no%2520audy%252080hz%2520sub%252014ft.jpg


Ok, looking good so far, but then all hell breaks loose after Audyssey auto-calibration enters the equation....
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Note: Audyssey makes the following changes (unfortunately I don't recall Front distances in the non-Audyssey measurements)
Front levels -0.5dB
Sub level -4.0dB
Front distances 9.0ft
Sub distance 14ft



Settings: Audyssey, 80Hz crossover, sub distance 14ft
https://lh4.googleusercontent.com/-ujlvzOivsE0/UwaZkVDwreI/AAAAAAAAA4A/cVKDK2SntjU/s800/mains%2520and%2520audy%252080hz.jpg

Still not too bad, but I really wanted to use a 60Hz crossover to take advantage of the Sierra-2's range and essentially eliminate any potential for sub localization.
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Settings: Audyssey, 60Hz crossover, sub distance 14ft
https://lh3.googleusercontent.com/-o7vM18iH76g/UwaZkYZLCCI/AAAAAAAAA4I/mFJMQpErmzM/s800/60hz%252014ft.jpg
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Settings: Audyssey, 60Hz crossover, sub distance 8.5ft
https://lh4.googleusercontent.com/-YmspTA4hXe4/UwaZlKY9t5I/AAAAAAAAA4Q/6IUe2-ADdGE/s800/mains%2520and%2520audy%252060hz%25208.5ft.jpg





Among many things, I guess I'm not understanding
1) Why am I getting such a large dip at 45Hz when switching from an 80Hz crossover to a 60Hz crossover? :dontknow:
2) Why is the activation of Audyssey introducing a rising slope from 40Hz to 80Hz in graph #4?
3) Is there something else besides distance/phase delay that can be changed to better integrate the sub/mains?

[curtis]

Among many things, I guess I'm not understanding
1) Why am I getting such a large dip at 45Hz when switching from an 80Hz crossover to a 60Hz crossover? :dontknow:
2) Why is the activation of Audyssey introducing a rising slope from 40Hz to 80Hz in graph #4?
3) Is there something else besides distance/phase delay that can be changed to better integrate the sub/mains?
1) I'm going to guess that you are getting some cancellation at 45hz with the 60hz crossover.
2) Audessey mic calibration and your measurement mic calibration don't match.
3) Not that I know of.

[TheHolyCannoli]

So where do I go next? Considering I can achieve a nearly flat response from my sub with equalization, I'm not sure if the sub position is the real issue. Currently it's centered on the front wall a couple feet behind the mains, and I would only be able to move it about 3 ft left or right against that wall.

Would it be reasonable to disable audyssey, apply further equalization to anticipate/correct the 45hz dip, then run audyssey again? Only problem is that if if Audyssey isn't consistent from one auto - calibration to the next (which I'm sure it won't be 100%), I'll end up chasing my tail trying to anticipate audyssey.

[curtis]

With Audessey and the 80hz xover at 14'...you got it pretty good. A lot of people would be extremely grateful with that kind of response.

I'd run a sweep with the speakers and see what the crossover region looks like.

[TheHolyCannoli]

A couple months ago, I would be one of those people. I think the greatest downfall of the REW software is that it gives you a quantitative means of striving for perfection. I feel like I'm neglecting the Sierra-2's with an 80Hz x-over, but maybe I'll stick with that for a few days. I'm thinking if I turn up the volume control on the back of the sub by 1 or 2 dB's, I can probably flatten out that Audyssey 80Hz/14.5ft curve even further...although by doing that without Audyssey "knowing", who knows what the curve will look like at other listening volumes.

I'll definitely have to run a couple more measurements tomorrow to take a closer look at the fronts.

[curtis]

It shouldn't be affected at other volumes.

[TheHolyCannoli]

Audyssey alone shouldn't change based on volume, but the Dynamic EQ feature would no longer be accurate. Forgot to mention that I want to keep the functionality of Dynamic EQ

[curtis]

Audyssey alone shouldn't change based on volume, but the Dynamic EQ feature would no longer be accurate. Forgot to mention that I want to keep the functionality of Dynamic EQ
Then you would have to apply the external EQ at the volume you want the FR to be flat.