Originally Posted by taurus1
it depends on how you're running your system.
if his main speakers aren't x-overed, then 75 Hz would be a good x-over point for just the sub alone.
you don't want the sub and main speakers pumping out the same frequencies because it will cause all kinds of negative side effects.
Good point. Once you get your sub output figured out and have continued access to the enclosure / power amp, you may want to consider adding an inexpensive crossover...like a Behringer. I see some going for $60-80 on E-bay.
The preset 75 hz sub-out was intended to supplement the mains as, historically, this is where we begin to see significant roll-off in the lower freq's. That being said, there's still a lot of bass energy (>75 hz) which I'd rather see carried by a decent, adequately powered sub enclosure.