How to get great audio from your computer

First step, you need a better digital audio to analog converter than what comes built into your computer. These are known as USB DACs and they plug into the USB port on any computer.

I've used the Audioengine D1 24-bit Digital-to-Analog Converter, these cost around $169.

This unit also has a head phone amp and a volume knob on the front.

 Next we need some speakers.  I found the best solution for the price are speakers with built in class D amps, such as these JBL LSR305 Professional Studio Monitor.  These cost around $285 for the pair. Notice that in these JBLs each speaker has it's own dedicated amp, other models of powered speaker pairs often only have the amp in one of the speakers. 

The JBL 305's also have a volume control on each speaker, bass/treble controls and a tuned port.

Total cost: around $450.  It's a bit pricey, but the sound you'll be hearing is going to blow you away!

Setup is very easy, anyone can do this, just plug the USB cable in between the computer and DAC and connect up the speakers to the DAC. The DAC has no power plug, power is supplied via the USB line, the JBL's have standard wall power plugs.

Very little needs to be done or installed on the computer, just go into your audio device control section and you should see the Audioengine as a new sound card.  Possibly you may need to install "pavucontrol" depending on your Linux distro, I needed that with Fedora/KDE.

Compatibility - of course everything I use works with Linux, the Audioengine D1 is plug and play, tested on Fedora 21 and a ThinkStation M93p i7-4770.  It also works with Android devices and every other computer I tested with (several Dells, Asus, Lenovo) so it should work with any OS or hardware.  

I've demo'd several "computer audio" speakers/amps from several makers (Klipsch for one came highly recommended) and can safely say, never buy anything labeled "computer audio".
The only way the Klipsch system sounded good was when it was turned off...

I ran in to problems with the  Modi USB DAC, it worked on Dells, but not on Asus or Lenovo, so once I upgraded my Dell desktop to a Lenovo the Modi was useless.  Modi's support was pretty useless too in resolving the problem, so I now own a less than 1 year old $135 Modi DAC doorstop.  I assume they knew they had a problem as they discontinued the Modi and replaced it with the Modi II, which is said to address issues with the old Modi not playing on some OS/computers.  

Personally, I don't trust this brand and would not buy again.