How do you use a sub with active speakers

DRubin -- I found the manual for the D3i on the Gamutaudio site, and I assume its specs are similar to those of the D3. It has an output impedance of only 75 ohms. Given that, and in the absence of specific design information on the driver circuitry, or credible assurance from the manufacturer, I would not want to short the two output channels together. You might want to contact Gamut and see what they have to say.

I notice that the sub has both a normal low-level input and an LFE low-level input. I have little familiarity with multi-channel stuff, but perhaps someone more knowledgeable about it can comment on whether it might make sense to send one channel into the LFE input, and the other channel into the normal low-level input. It looks like there are independent volume controls for each on the sub.

Regards,
-- Al

Interesting idea, Al. It might work.

On second thought: while the LFE has its own volume adjustment, it does not have a crossover adjustment and doesn't utilize the crossover setting for the hi/low level input. Because it is intended to take the purpose-made LFE or .1 signal from HT, it runs full range. That wouldn't be good.