Gain control for low-pass bi-amp

I’ve never been a fan of biamping with amps that have different input/output parameters, gain and power. If you aren’t using active crossover and not removing (or bypassing) original passive speaker crossovers, your dynamic range will be greatly compromised to listening at certain volume, but not higher or lower to reach maximum coherency and balance not achievable with passive built in speaker crossovers at all. Even after adding any passive volume control you will still have balance and coherency issues at certain volumes!

You’ve already tested your extremely poor idea, now you are in front of choice whether to use original built-in speaker crossover or bypass it pretty much cancelling the speaker voicing and qualities with active crossover which may or maynot benefit.

If you are looking for the increased power, I’d recommend swapping for more powerful amplifier or monoblocks.

The only way of successful biamping that I see is to use 2 SAME amps in case if 2x lower poweramps is below the price of one powerful amp

Any passive volume control on the bass amp will work for you, no reason to make it very expensive, but if you wanted to spend a little money, I’d get a miniDSP AND bypass all of the low bass woofer’s crossover.

This would take some careful measurements to ensure you set up the external crossover correctly but I suspect this will greatly improve the overall performance.

For more check this thread on DIYaudio about those speakers.

Alternatively, you might want to see if anyone has after market crossovers for these speakers.  Like other Infinity designs, the impedance curve left a lot to be desired and was unnecessarily brutal on the amps.

Thanks for the responses, guys. I posted this in a leisurely part of a vacation that quickly turned busy. Ordered a passive volume control, but after playing with the stereo more upon returning home (volume control still having not arrived), I have come to the conclusion I have accumulated a mish-mosh of equipment with questionable synergy, if any. Learning a ton as I go, here.

And you're right, @erik_squires , the Infinity impedance curve is gnarly. I knew this going into it, but their sound really moved me, and it still does. I've been buying equipment around the speakers, and that's probably the worst possible idea with the K9s. There are aftermarket crossovers, and considered that in the past, but it's not really my forte, nor enjoyable.

So I'm sort of at a crossroad, as @czarivey suggests. For a while I had been kicking around the idea of selling everything and starting over, and that's where I've landed. Need to rip off the Band-Aid, take the bath, and move on.

Thanks again,

Richard