Crossovers, why so few options?

I'll mention that even if subs provide bass management, there are some problems with this arrangement. Suppose you have a tube preamp and stereo subs. The input impedance of sub amps is usually pretty low (~10k ohms), and with 2 amps it works out to 5k ohms. This makes it pretty problematic to run line-level outputs from preamp to sub amps.

In addition, if you wanted to run speaker-level signal through the sub to the mains, the sub's high-pass filter frequency/slope is not adjustable without a hardware change.

It seems like the only solution is an external crossover...

This is my dilemma. I need a preamp with sub out and adjustable high pass crossover. While some have the sub out, most do not have the crossover, where you can employ a highpass to the mains.

Sucks having to choose between only a handful of preamps that have sub out and adjustable crossover: parasound, rogue, emotiva -- not much else.

Well, this little pond is not representative of the audio world at large. Consequently, the volume demand for this type of product is limited. Some reasonable suggestions have been made. The SMS-1 is one but it is limited to only 80Hz for HP. Consider also the Parasound P7 preamp with adjustable crossover. For more complex/sophisticated installations, there are the pro and DIY markets.

Kal

Kal...The passive crossover elements which address driver characteristics can be retained while the basic HI/LO filtering is done at line level.