Apr 20 2020, Michael Jarosch has written:
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Unfortunately, I don't know professional grade audio devices offering 2
balanced (XLR) input and >4 (preferable 6) balanced (XLR) output ports.

...
I'd second the Scarlett 18i20, there apparently are drivers now, even
for the latest generation.

I guess, I'd be more precise in my needs to prevent starting a flame war about the best sound device on linux… :)

I'm searching for a more DIYish sollution. It needn't to be in a case.

Anyone knows the HiFiBerry DAC+ PRO XLR? Unfortunately, there is no input and as far as I know you can't cascade it to a 4/6-output device. But something like that would keep the price low. Of course, using Linux and not being dependent by a company is a value for itself. But it doesn't make sense to me using a sound device that alone exceeds the price of a brand new DBX DriveRack.

A LADSPA virtual crossover network doesn't need much performance. I like the idea giving obsolete audio devices and PC hardware a new life. Compactness and quietness, on the other hand, does matter. Combining a Raspberry Pi 4 with an Echo Audiofire 12 would be a killer. Unfortunately, there's no GPIO2Firewire…

By the way: In the home setup for my music production PC, I'm using a RME HDSP 9652 for a 4.1 setup. The satellites have no passive crossover, so I need 9 outputs and 9 amps. Carla's my virtual crossover network, I'm using Pere Ràfols Soler's EQ4Q for filtering.

I'm thinking of a "speaker controller" for places where I work that want to improve their sound infrastructure. Being cheap but powerful / high quality is the challenging way to go, there… :)

Greets!
Mitsch