Ok sorry for disappearing. I don't frequent this forum, just stop in from time to time to harass
@shadyJ.
I meant that you should lower the crossover point on an individual sub, as in use its own built in LPF.
I know I know, but isn't it bad to compound multiple crossovers? Doesn't it screw up the sound? Well, not really. paralleling two 2nd order BW filters gives you a 4th order L-R filter. So we aren't talking about much different here. What it does is technically make the filter steeper, but as I said, the entire goal was to take advantage of that fact, since it changes the shape of the response. It adds group delay, but so does any higher order crossover. You can compensate for that by adjusting the delay. Make the sub farther away, or...rerun Audyssey, it will automatically compensate.
In my own system, I have it setup so the main speakers run full range. A global 150hz 2nd order LP filter is applied. I have a total of 4 subwoofers placed in various locations around the room. One is in the front left corner, one is front center, one is right front 1/3, and the other is left rear 1/3, roughly. The front two subwoofers are operating from 150hz and down. The next closest location to the listening position is crossed at 100hz 1st order. The last subwoofer is crossed at 80hz 1st order. In practice the slopes are steeper than that because of inductive losses and because of the cascading crossovers at 150hz and 100 or 80hz. This arrangement creates minimal excess group delay from the filters and provides for good integration.
So the rear most subwoofer isn't actually crossed at 80hz however. Because I wanted to get a flatter response and it had too much upper bass, I actually set the crossover at closer to 60hz and turned the level up. If you saw the response of just that sub, you would swear it was crossed at 80hz (it effectively is), but the electrical slope is much lower.
In general it is best not to focus on numbers and rather on results. A crossover point is fairly meaningless if the speakers response is not flat. The response of most speakers are not flat, even subs, which are very smooth typically, are not necessarily flat. All speakers are bandwidth limited, they all have a high pass filter. Maybe not electrically, but certainlly acoustically. Depending on the way the sub's response rolls off on the bottom can make the placement of the low pass filter as much a low pass filter as EQ.
