[hebrewbacon]

So I've never owned a soundcard or other DAC other than what's built into my motherboard. What have I been missing?

 

 

[Chs177]

It's depend on what other equipment you are using and a type of connection also.
For example, if you using a simple headphones or speakers you are missing a little bit in the soundstage and the sound quality.
If you are using a good headphones (with good amp may be) or a good speakers (with good amp may be ) you lose a lot in the soundstage and the sound quality.
But if you are using spdif (coaxial or optical) connection to your amp or DAC  you lose nothing or a little (depends on a quality of build-in soundchip and oversampling).

 

[kalston]

Not all onboard audio is bad and not all is good. So it depends really. I've had some that sounded allright (even quite good) and had no static/weird noise etc but others were simply abysmal (on my laptop for example). 

 

[SnTholiday]

For as long as I can remember I have always used the S/PDIF output from the motherboard to a hometheater receiver. Then I built an office PC and connected the onboard audio (Realtek ALC888 I believe, speaker output) to a Harman Kardon HK3390, which is an analog receiver. There was something missing in the music, no real soundstage or depth, either with bookshelf speakers or headphones. So I connected the S/PDIF out (coax) to an old Soundstream DAC-1 I had lying around and the sound opened up. I could hear a depth and soundstage to the music that wasn't there with the speaker outputs of the motherboard. I am not very good at describing how music or equipment sounds, but there is just a kind of emptiness to the music using onboard audio. When you consider the price of a decent motherboard vs a decent DAC or soundcard you realize how much quality goes into the onboard audio.

 

[Nagasaki_Kid]

on board sound lately has been okay/decent. the last 2 laptop I've bought both have idt sound chips which is the company that bought sigmatel. They sound almost indistinguishable from lower end creative sound card that uses sigmatel. 
but you'll get more detail, tighter bass and more bandwidth at both ends(higher high/lower lows)