Will an external DAC improve music audio quality for me?

[The Computer Audiophile]

3 minutes ago, Gamboge said:

I have a motherboard with ALC4080 HD Audio and use Aria iems. My budget is under $150. If I buy something like the Schitt Magni+, will music sound better? I sometimes play games, but not that often, so it's not as much of a priority.

The unfortunate answer is that it’s impossible for anyone to tell you it will sound better/worse/different. 
 

It depends on the type of music you listen to (EDM, Metal, classical, etc…), your ears, your perception, IEM sensitivity, music sources, quality of the motherboard and many other things. 

[The Computer Audiophile]

2 minutes ago, Gamboge said:

Aren't there objective numbers? Or at least a general consensus?

No objective data can tell you if music will sound better to you. Do you listen to 64 kbps internet radio streams of death metal and or well recorded high resolution classical with a lot of dynamic range? When you turn up the volume do you hear noise from the motherboard?

[The Computer Audiophile]

An external USB DAC may have better specs and more power, but neither of those tell you anything about what you’ll perceive. In addition, the ALC4080 on its own doesn’t mean much. The motherboard designer could make it pretty good or terrible. 

[The Computer Audiophile]

3 minutes ago, Gamboge said:

I'll listen to lower and higher resolution audio at different times. I don't strictly stick to a particular genre or quality. When comparing the same audio played with onboard to with a DAC, is there no difference unless the audio is of a sufficiently high quality? Also, I do not notice any static of otherwise unusual noise when the volume is high.

Good to know. 
 

Audio = garbage in / garbage out just like everything else. 

If you’re a perceptive listener the chances are good that you’ll enjoy a better DAC (given what you’ve stated). If you only listened to low quality dynamically compressed death metal, then it may not matter. Nothing wrong with that though. 
 

You’ll really need to try it for yourself. Nobody can tell you what your subjective experience will be. 

[The Computer Audiophile]

Keep in mind that everyone here is an audiophile. We all have external DACs and love them. Our significant others often wouldn’t notice the difference between onboard audio and an external DAC. It’s all personal. 

[The Computer Audiophile]

53 minutes ago, Gamboge said:

I have an aorus b650i. Can't find much discussion on its audio quality.

Don't know how I missed that. Guess the Schiit Modi 3E is what I meant. Not sure how that would affect the "impedance matching" though with the built-in amp. What I'm getting from this is the only way to know is to actually try it?

Here’s an example of a motherboard with good audio design.