Answering your original post:
I do not have much knowledge of the typical consumer DSP solutions. From my understanding, the typical way of accomplishing this would be with separate DSP units for the speakers and your subs (Say a MiniDSP 4x10 for the speakers, and a 2x4 for the subs), with some kind of preamp upstream for input switching and volume control.
Therefore, I will speak to my knowledge, which is the Pro Audio DSP world, or at least the installation-focused DSPs.
- It seems like you are looking for a system which can handle DSP processing, with 12 speaker outputs, and I presume a number of digital or analog inputs.
So that is our I/O requirement, and the limiting factor (as far as system hardware options) here is going to be the 12 outputs. If you don't already have amplifiers, you could theoretically use a digital protocol like Dante, Cobranet, or AVB, to send the audio to the amplifier(s), but these protocols do not usually run at > 48khz sample rates, and can introduce latency, along with network requirements (For example, a 5-port AVB-capable switch is like $400, Cobranet is obsolete at this point but is cheap, and Dante DSPs and amplifiers are crazy expensive).
- A good analog section for the analog I/O. This is another limiting factor. Many pro-audio DSP solutions aren't designed with the best of analog performance. From what I have heard, some manufacturers (BSS, Allen & Heath), have better analog performance than others like Biamp, QSC, etc. However, I cannot directly speak to the analog performance. What I can say, is that to me, a Biamp TesiraForte, running with line-level inputs, sounds fine, and based off some loopback measurements I performed, is transparent.
- Physical volume control / remote, with physical input switching. Pro DSPs here are going to falter, as they are usually designed to be controlled by networked remote, wall or table mounted control devices. For example: The
Biamp TEC-1, various
Crestron touch-panels, or sometimes physical devices like the
Biamp Volume 8.
In the TEC-1's case, it can directly control a Biamp Tesira system, assuming you program it properly. Crestron touch panels require a Crestron processor to run, and the processor can control just about anything. The last category can get a bit messy, especially when you factor in proprietary control interfaces like the one found on the Volume 8.
Currently, my Tesira setup is controlled by using a small windows control surface (Biamp Canvas). I don't exactly "switch" inputs in the normal sense, as all of my inputs go into a few mixer "blocks" (In the DSP program), and I just mute / unmute them as needed, and often leave multiple inputs unmuted and use other devices to control it. For example, I have a direct USB input, and my computer's stereo analog input, into my system. The USB input is setup for zoom / teams calls, and my analog input is for music. I leave both unmuted, but usually nothing is connected to the USB input, and the volume control on my Focusrite intereface (PC -> Focusrite -> analog to Tesira), is turned down.
So basically, Pro DSPs have incredible control capabilities, and usually publish control API specifications. However, it is up to you to figure out how to control them without breaking the bank. (A word of warning: Some companies like Crestron don't allow you access to programming software, so if you get their hardware, it is effectively useless without the programming software. Do your research before buying anything!)
- Dirac Live. Nope. Not here. Biamp Tesira can run quite a bit of FIR filters, and so can many other pro DSP solutions, owing to the massive horsepower they
usually have. But I have yet to see something like Dirac Live integrated into them.
- Balanced interconnects. Any good, modern pro DSP will have balanced I/O. The catch is that, at least on installation-focused models, the I/O is usually terminal connections. (See the
Biamp TesiraForte, scroll to the bottom of page 2) So basically, if you have wire strippers, cutters, a multimeter, and can wire things, then it's fine. Otherwise, you should look elsewhere. One thing to consider is potentially using Dante or AVB to send audio digitally (over a network) to your amplifiers, but you should do your own research on that.
So some jumping-off points to consider:
Various companies make Live sound (ie, concerts, PA use, etc) DSPs, a few to look at are Lake processors, and the Meyer Galaxy (or whatever the new one is).
In the Installation world: Biamp Tesira (Nexia and Audia are old and underpowered), QSC Q-Sys, Symmetrix Prism / whatever the new one is, Allen & Heath AHM, and BSS Soundweb.
From the internet, people seem to think that the BSS products "sound" better for live music and other applications. They are also part of the Harman family which means integration with JBL speakers, and other things. I cannot attest to any of these claims, and my opinion of their product lineup is that it is a confusing mess.
So hopefully this helped you at least start somewhere!
One last thing: These companies often have free / openly available training resources, so if you are interested in learning about one they probably have resources available.