crossover frequency settings on PSW250?

[workflow]

My amplifier has a subwoofer output whose cutoff frequency is 90Hz. I just got a PSW250 subwoofer which doesn't have an unfiltered LFE jack, so I have to connect my amp's subwoofer output to the PSW250's left line input.

What I'm confused about is the PSW250's crossover frequency. It is adjustable between 80-160Hz. Since it's a low pass filter, what it means to me is that if I set it to be higher than 90Hz, it should not filter out any signals coming from my amplifier, which is what I want. Is this correct?

Also, is it necessary to actually use a Y-adapter to convert the single LFE output from my amplifer to both the left and right line inputs on the PSW250? Would that be necessary at all?

Thanks much in advance

[Dr. Spec]

Set it all the way up. The filter rate at the receiver is 24 dB/octave. At 90, the sub will still see some content from the receiver. Set it at 160, and the sub will literally have no signal content to filter at all and you'll be OK.

You don't need a Y splitter - either input (L/R) will work fine.