Originally Posted by TrueOptic
Like could someone provide an example of a sound system (or even headphones if applicable) that would benefit from a dedicated sound card?
It greatly depends on what you're doing with the audio (listening to music, listening to movies, and gaming for example). And it depends on the quality of that source material that you're going to listen to (low bitrate/sampling isn't going to upscale, and high quality bitrate/sampling isn't going to be appreciated on some mono duds). And then it depends on what equipment you're listening on (headphones or speakers).
What it basically comes down to is quality of all
the components involved.
I've tested the onboard RealTek sound on my motherboard and compared it to my Auzentech Cinema Xplosion and to my Vivid Tech V1 DAC. That's onboard vs dedicated soundcard vs external USB DAC. I've tested them all with my headphones (Sennheiser HD580's). And I've tested the optical/spdiff out to my Onkyo TX-SR308 receiver out to my Polk Monitor 40's, 30's, etc surround setup.
Onboard vs Auzentech vs V1 DAC
Absolutely cannot use this with high end headphones. It doesn't have enough voltage, no swing, it's not adequately amplified. You can only use your onboard sound with low impedence rated headphones. You could for example use high quality headphones with 16~32ohm rating, but even then, you won't get the full potential of those headphones due to the onboard simply not having the power essentially to push them the way they were designed. It literally comes down to wattage output, volt swing, and of course quality of components involved. Basically, onboard doesn't have a good amp, or any amp really for that matter, and can only be used with very specific kinds of headphones. You strap on some nice hifi headset and you'll find out real quick it doesn't even come close to driving them.
The Auzentech has more capability with higher end headphones simply because of it's OPAMP and the ability to swap them (all Auzentechs can do that actually). So it can drive higher impedence headphones, like my 300ohm headphones. Onboard just can't push high impedance headphones. So it's a simple comparison there. If you have/want nice higher end headphones, you'll want something with an amp. Even the Auzentech can't push the full potential of my Senny HD580's. Not even close. I'd have to get something like the Xonar STX for that in sound card form.
But instead, I use my Vivid Tech V1 DAC/AMP. It can drive my 300ohm headphones nicely and the sound quality is superb. Best of all, it's portable and is USB so it connects to any system and has built in battery for when I go portable and can listen to my nice headphones on the go. If you're into headphones at all, you will not
really want a sound card unless it's specifically for gaming. For music, a headphone enthusiast is going to have an external DAC, an external AMP and some really nice headphones. Anyone into this stuff already knows not to even think of onboard audio options when it comes to computers.
Granted, my Onkyo receiver doubles nicely has a headphone amp for my HD580's. So my onboard can output to my receiver which then amps my headphones. So it can drive the nicer headphones. But, we're talking about a Receiver doing the work, not the onboard audio solution, and receivers are way more expensive and powerful than even a good soundcard. So this should be a no brainer.
When connected to optical out and used as SPDIFF output to my receiver, the sound quality is actually quite good. I can't tell the difference on my loudspeakers between onboard compared to my Auzentech when I turn off the equalizer and turn off all extra "software" effects that the Auzentech has available. The sound quality is pretty close. I do however notice that sound positioning is not as good on the onboard compared to my Auzentech. On my Auzentech with Dolby Digital Live enabled, sound positioning when watching movies is quite different and sounds superior to me. I hear the surround effects more with more movement in more directions. The onboard does fine, and sound quality is quite good, but I just don't hear as much movement in the same scenes on films I've tested. The channels just didn't seem as separate so it seemed flat to me. This applies to games as well that take advantage of 5.1+ setups for me.
So in all, onboard is great if you're just using very entry level headphones that have little to no impedance. Onboard is also ok if you're just using it for a passthrough via optical/SPDIFF to a receiver. It's just passing on digital signal and the receiver becomes the DAC where digital becomes analog for you. A lot of HTPC's just use onboard solutions for sound because they output to the receiver. Simple as that. If you actually plug speakers into the onboard, the speakers are likely of low quality or are made for "computers" which again is pretty much (not always) lower quality. That doesn't mean bad. It just means a pair of logitechs are not going to sound like a pair of energy speakers. And the prices are appropriate with that too. You pay for what you get there to a point.
Onboard is fine if you're just using it for optical/SPDIFF output to a receiver.
Onboard is fine for cheaper low impedance headphones.
Soundcard is better for amplification to nicer higher impedance headphones.
Soundcard is better for additional options for sound manipulation (ex. DDL). This is where gaming comes in where sound positioning actually matters (competitive online gaming comes to mind). I find movies sound better, more channel separation, less flat sounding, with a good soundcard compared to my onboard--this is my personal experience, not fact.
DAC/AMP is better for headphones. And is the top choice for high end headphones.
Onboard is actually quite good these days. But again, if you're using higher quality audio equipment, you'll find out real quick is just can't power them and the audio quality isn't the same as something dedicated and higher end that is built for the application (ie, DAC).
That said, a $200 soundcard for some $50 headphones/speakers and some 128Kbps MP3's is not going to be a wise investment--just use onboard if that's the camp you're in (unless gaming and sound positioning, ie, 3D, matters beyond all else).
Overall, I would suggest a decent sound card to anyone. Again, I find separation of channels is better on my sound card than the onboard solution for my HTPC (even though the sound quality is the same to me). So simple things like that can still be a big deal to you.