Thanks for your reply.
I'm not sure the low frequencies of the subs dictate a converter. That is, if the full range signal makes it to the subs, they'll just ignore everything above their response range. It shouldn't adversely affect them. I agree, if the user only wants the lowest of the lows going there, then some sort of filter will be needed, but, IMO, the big, bass speaker is sufficiently its own low pass filter.
As for needing an extra amp, I'm under the impression that the sub amp won't adversely load the radio. It should still present a fairly high impedance load to the radio speaker outputs. I ran my sub amp off the signals driving the rear 6x9's with no ill effects.
I suppose, if the hi-lo converter has a volume control, the big benefit is that the user will end up with a separate sub control knob. That's one thing I wish I had.
Doug
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