3.1 or 2.1 Home Theater setup for desktop


So I am trying to setup my own hifi 3.1 setup (left,right,center,sub) and I was wondering how I should go about this. I have been trying to absorb as much knowledge as I can in doing this endeavor on my own, but I am left with so many questions and I would love to hear from others on their recommendations.

Now for the build I am running off a near $1000 budget and wouldn't mind it being cheaper than $500, but can work up to $1000. From what I have been reading, I think I would like to incorporate a tube amp instead of SS if possible, but it's not a requirement. I want the center speakers and the left and right speakers to hopefully not be too big as it needs to fit on a standard sized desk. Not that it needs to be stated, but high quality listening experience when at the desk is what I am aiming for. It'd be for everything (Music/TV/Gaming/Youtube Videos) I would love to hear everyone's suggestions.  

Also the center channel can be optional if that helps.
thatcdac
If you really want a center channel, probably the easiest way to do this is get one of the higher end multi-channel sound cards, such as one of these:

I'd prefer to avoid any internal components on my computer as their very well might be issues with space/open slots as well as compatibility with Linux as I go between using linux and windows.
Look into Sonos Playbar and Sub, this combination is super easy to setup. I have yet to hear anything at this price range that can rival its superb sound.

I have been using this setup in two of my rooms for last 12 years and never felt the need to try anything else. Visit Sonos.com for many speakers options to pair with their sub.

https://www.bestbuy.com/site/sonos-playbar-wireless-soundbar-black/8028043.p?skuId=8028043

https://www.bestbuy.com/site/sonos-sub-wireless-subwoofer-black/5589100.p?skuId=5589100
The problem with Sonos is that it only has HDMI/optical inputs.  No USB input.  Plus, if you really want a sub, $599 will get you a rocking Rythmic sub which is going to be a lot better than the Sonos for the same price.

I would do this in stages. Look for a USB DAC with a volume control.  These are a couple that are not too expensive (for what they are), but are about half your budget.  You can get them for less used on ebay or other sites:

Parasound ZDac
Cambridge Audio Dacmagic Plus

Both of these or USB DACS and have both XLR and RCA outputs that can be used at the same time.  Look for some nice powered monitor speakers.  Think Yamaha HS5 or other powered monitors.  You can add a powered subwoofer of your choice at any time in the future using the second set of outputs from the DAC.

Alternative, you could go for that tube amp and look for some nice bookshelves (Elac is the only one that comes to mind that is cheap enough but still very good).
auxinput,

You do not need USB input with Sonos. If I read OP requirements correctly, he will be connecting Sonos Playbar with his TV and for that all he need is optical input.

I am sorry to say, everything you have suggested has ‘clutter’ written all over it. Consider wires, space and synergy between the desktop speakers, sub and DAC. And then look at two piece Sonos setup.

For a compact 3.1 system with a sub, there isn’t anything better than Sonos. Great app, wireless connectivity Unless you try and listen, you just never know it’s true potential.
you will love a darn good office system.

I just set up my office, best sound I ever had here. first, I rebuilt/re-positioned my desk to allow a perfect equilateral triangle with my mains which are non-ported bookshelf speakers. I picked and bought used B&W D100i. (6-1/2" woofer size).

My desk is pulled back away from bookshelves on front wall, creating the triangle, leaving an aisle to access the shelves, but importantly allows locating my self-powered sub, old velodyne 12" re-coned, on the floor between the shelves and desk, tucked back, aimed sideways, simply adding low bass, not directional. I just add a bit of bottom with the sub, unaware unless you turn it off. wires from computer to sub, to adjacent bookshelves.

get the tweeters seated ear height as always.

separating low bass to the sub first, sending the rest to the amp/bookshelf mains is good, the amp and mains do not need to try and produce low bass.

four advantages:
1. bookshelf mains do not try to make low bass.
2. not trying to make low bass is how you successfully avoid bookshelf speaker designs relying on ports to try and make low bass
3. amp can be lower power, smaller, more affordable, more location options.
4. sub’s amp can be powerful to control woofer without costing a great deal.

I love tubes for my main music system, but you may want to rethink tubes, because the computer is on a great deal of the time, even when out of the office (the kitchen!), and when working, not listening, making heat, burning watts all the time.

I would not add a center channel to the mix, just get yourself the best centered listening position.

Prior to this, I was off-center and relied on the balance control to center things, ok, but centered for real is wonderful.

Video images perfectly centered to the sound is terrific.