Originally Posted by Mark Seaton
I suspect your trying to "get the crossover right" might be at the core of your headaches. Your receiver makes some assumptions and recommends/sets a crossover... you can most certainly change that after Audyssey has run and still use Audyssey as most end up doing.
What were you doing to get Audyssey to suggest different crossovers?
Thanks for the input Mark! I suspect the same
Originally Posted by lennon_68
Now note, in my effort to get Audyssey to set the XO to the correct frequency I had inadvertently given it a bit of a mess to start out with but nothing like this!"
That said you can see it wasn't just me messing with things though. The 2nd pass of Audyssey took the very decent starting point of the gold trace (that was a 60hz crossover) and made it the green one throwing away 10dB of headroom.
Trying to get Audyssey to cross where I wanted I was putting different high pass filters on my mains (passive TM and active W using DCX2496). It got a bit more complicated though as I was doing EQ in phases - I ran audyssey then measured the preouts to see what Audyssey had done and tried to mimic that with filters in the DCX (where the filters were very close for both L&R speakers). I did the same thing with the subwoofer but it was a very "odd" filter that Audyssey had used. It had made a large wide cut centered at 40hz then increased the overall level by like 15dB (something like 40hz, -15dB, wide Q, I don't remember at all what it was). When I got the first result above (light blue trace with 10hz at like +30dB) I had that filter still set in the DCX. It looks like it basically did the same thing again - made cuts, etc then increased the overall level by 15dB resulting in the +30dB.
Darn! I should have measured the sub preout to see the actual signal it was sending the sub! Really it was supposed to be a quick re-run of Audyssey after getting the speakers "closer" but it turned into something very amusing and I just had to share
Regarding changing the crossover after Audyssey has run. For some reason I thought Audyssey could/would help get the phase properly aligned through the crossover it selects but might not necessarily have corrected it for a different crossover frequency. I could certainly be way off base though as that was just an assumption I made.
One good thing did come out of all this, I had a major "Duh!" moment. I'd never been able to get the crossover right when using the built-in XO on my AVR but Audyssey seemed to have no issues. To get Audyssey to set it right I had put a 70hz 12dB/octave LR HPF on the woofers in the mains. After Audyssey did its thing and I measured to find the integration pretty good I tried removing that HPF to see if I could get that hole at 90hz to fill in some. I found a peak and null at the crossover frequency now - similar to what I've always ended up with when using the build-in XO. I didn't think much of it last ngiht but this morning it hit me. The XO in the AVR is usually a 4th order LPF on the sub and 2nd order HPF on the mains. The 2nd order HPF is supposed to sum with the natural 2nd order HPF that the mains are supposed to have to provide the matching 4th order of the sub XO. Because my mains remain flat lower than where I was trying to cross using the XO in the AVR without an additional HPF on them was resulting in asymmetrical XO slopes giving me the nastiness I always found at the XO.