ARC was being picky

[CB22]

I downloaded the new Arc Genesis yesterday. It did a great job taming the bass with some help after the fact. A night and day difference and be heard while listing to music with it on and off. I used to turn the room correction off when listing to music but now I think I prefer music with Arc on. While running the room correction Arc keep telling me to turn down the sub volume more and more and more. I had to crank it down to -20db for it to take the measurement. The bass seemed almost nonexistent in the music. So I turned the volume knobs up to -5db to suit my taste. It's kind of strange I had to turn both subwoofers down that much to do the measurement and then turn them right back up again. Any ideas whys?

Check out the PDF attached to see the specs.
SUBWOOFER(S)
Subwoofer Crossover Frequency (or Low-Frequency Extension): 250 Hz High-Pass Frequency: 43 Hz
High-Pass Slope: 3rd
Minimum Correction Frequency: 36 Hz

Any idea what high- pass slope 3rd means? how does it affect what the AVR and the subwoofers are doing? I found this online but not really sure what it means relative to room correction.

"You might also want to consider the filter order or slope (first order or 6dB/octave, second order or 12dB/octave, third order or 18dB/octave, fourth order or 24dB/octave and so on). Not all filters are created equal and while a 30Hz, first order BW low pass filter and a 30Hz, fourth order L-R low pass filter may both have the same corner frequency, they would also have quite different associated responses"

 

[ryanosaur]

Any idea what high- pass slope 3rd means?

that's the 3rd order, 18dB / octave.
It's crossover acoustics, and how fast they roll off. Think about your BMRs... I think Dennis likes 4th order L-R filters, and whether he builds them directly or uses them summed acoustically, he does employ them. The important thing is about protecting drivers from damaging frequencies at volume. If a woofer will over-excurse at say 34Hz @105dB, you want to roll that off with a high pass filter far enough above that point to avoid potentially blowing it... so an octave above is the common choice with most Bass Management. So if you set a 4th order LR slop at 80Hz, it would be 24db down at 40Hz... and lower still by 34Hz... thus protecting the driver.

I'm still new to most of this CB, so I can't claim expert status on everything I'm saying, however, if you wanted to try a 3rd order slope, half an octave above the 34Hz point of the BMR, you would set that at 51Hz (if you could select it, that is) and in that 1/2 octave range, the roll-off would be -9dB at 34Hz. If you did the same with a 4th order slope, it would be -12dB at 34Hz. Safer for the driver, yes.

Which is better? Especially in terms of BM? I am not the person to answer that.

But I hope this helps you make a little sense out of that!