I have a Magni 3 and Modi 2 Multibit on the way, just to preface this. Sound Blaster Z on Win 10. Still not sure the best solution to connecting everything (even after reading
this thread), whether I should run the speakers through the Schiit stack and connect the Modi to line out (losing SBZ's headphone audio processing in games), headphone out, or some other solution like dual amping/using optical.
Dual amping isn't a good thing. That's why if you use optical output from the soundcard to the DAC-HPamp or a DAC, you send out a preamplified signal to the amplifier for the speakers from either the DAC-HPamp or the HPamp. That's a good way to control powered monitors for example since each cabinet has its own amp built into it and each has its own gain knob. Alternately, you can use passive speakers with a dedicated power amp, ie, the amp doesn't have its own preamplifier stage.
Since you already have the Modi2 and Magni3 on the way the easier way to get 2.0 speakers integrated in there is to add powered monitors since all you'll have to do is hook them up to the Magni3's preamp output. Also, you can't "connect the Modi2 MB to line out" as it only takes digital inputs, then sends a line output signal to the Magni.
However, regarding the DSP, that would mean that when you switch over to speakers, you have to disable Headphone Virtual Surround. Using an integrated amp connected to the soundcard's analogue FL-FR jack is one option,
but you have to take into consideration that:
1. This isn't as straightforward as taking off the headphones and lowering the HPamp volume as you'll likely have to select the output between SPDIF optical and analogue. That means you'd still go into the DSP suite anyway, on top of which, you might still have to disable virtual surround as some soundcards allow that through the FL-FR jacks in case you connect its analogue output to a headphone amp.
2. You'd have one extra box on the desk, whether its a small, low power or relatively high power output but small Class T or a huge Class A/B integrated amp.
Powered monitors are also designed for nearfield use, so they're really more suited for this application anyway.
I'm just looking for a 2.0 setup to replace my Klipsch Promedias preferably with the option of expanding to 4.0 (maybe 4.1) later. I figure if I don't run the speakers through the Schiit stack then adding rear speakers would be as simple as connecting them through rear out on the soundcard? But if I ran it through the Modi I'm thinking I'd need something like a 4 channel amp or receiver to achieve that?
This is where it gets tricky. You could run 4.0 via the FL-FR and RL-RR combo jacks, but then you'd have two amps. Or run a preamp with two power amps. All of which just adds more clutter and could potentially cost nearly as much or even more than if you just did it properly.
If your goal really is to have surround speakers and headphones, you can just save up and do the speakers later, and use an HT receiver. Just make sure the receiver can run Phantom Center on the two mains (or just get a Center channel), and make sure that there isn't any conflict between the soundcard drivers vs the graphics card or motherboard HDMI audio drivers.
Alternately, if the speakers aren't for reference music listening much less recording/mastering, why not just get a multimedia speaker set? They're smaller, and you won't need the midwoofers to be as large if you're not going to be very specific about imaging (ie, not having the sub reproduce a wider range to compensate and end up pulling the bass image to where it is) like how hard percussion hits and loud bass guitars can be easy localized if not enough of their sound is coming off the midwoofers set at a proper height. You'll run these completely off the soundcard without adding too much clutter (you also need just one power cable) and you just switch which output the soundcard will use.
Based on recent recommendations (and a $300 USD, maybe 400 budget) I've been looking at JBL LSR305, Alesis Elevate 6, Kanto yu4... or something more elaborate like KEF Q100 + SA-98E. It's quite a bit to digest and research. I'm toying with the idea of giving up on ever really expanding the setup past 2.0 (and just using headphones whenever I want positional audio in games), but thought I'd check to see what other solutions might be out there.
Controlling those will be problematic unlike having a single receiver or multimedia set with a volume control plus a separate sub gain (which, on the HT system, will be either on the active sub's amp or on the receiver itself - set the sub and later adjustments can be through the receiver).
