Subwoofer crossover frequency control?

[Flash]

Do any soundcards have the ability through software driver settings to
control:

Crossover point of subwoofer (low pass setting).

Crossover point slope (db/octave of the low pass filter) - 24 db/octave
is ideal so the subwoofer isn't messing up the midrange.

Audio level of subwoofer (volume of sub).

Then I can use any speakers with a power amp for my subs at the best
settings. Lots of speakers have great bass and small power amps are
cheap. And there are lots of great little speakers for the main
speakers. I would run those full range, or, if they are sensitive to
bass dynamics, put a capacitor on the input of the power amp to act as a
6 db/octave high pass filter. Then there are no phase issues.

[Sharanga Dayananda]

Most Creative soundcards have a crossover point adjustment. However, the
redirected frequencies are attenuated by +10 dB so the subwoofer many be
weak on the Audigy cards.

There are no other adjustments other than subwoofer volume.

Post by Flash
Do any soundcards have the ability through software driver settings to
Crossover point of subwoofer (low pass setting).
Crossover point slope (db/octave of the low pass filter) - 24 db/octave
is ideal so the subwoofer isn't messing up the midrange.
Audio level of subwoofer (volume of sub).
Then I can use any speakers with a power amp for my subs at the best
settings. Lots of speakers have great bass and small power amps are
cheap. And there are lots of great little speakers for the main
speakers. I would run those full range, or, if they are sensitive to
bass dynamics, put a capacitor on the input of the power amp to act as a
6 db/octave high pass filter. Then there are no phase issues.