Demystifying onboard audio

I decided to demystify onboard audio in “gaming” motherboards after realizing people ask about it a lot, and there isn’t a lot of clear information about the topic.

I would like to clarify, I am not an audiophile, I am a gamer in my free time and a geophysicist in my not-free time. I work with seismic signals and I am considered a digital signal processing expert in my area.

The first thing people need to understand is that a DAC reconstructs a digital signal into an analog signal. A DAC that changes the original signal into another signal, it’s just a bad DAC, unless you want to change the signal intentionally for a very specific reason. The same goes the other way around, when you record an analog signal to store it digitally, you need an ADC .You want to preserve the characteristics of the analog signal the best you can.

The AMP shouldn’t change the characteristics of the signal either, it just amplifies the signal, but the signal should remain the same.

So, DAC and AMP reconstruct and amplify a signal, it should not distort/change the signal. But we don’t live in a perfect world, so there is electronic interference, distortions, etc.

There are several measurements to assess how good a DAC is at reconstructing a signal without introducing distortions, noise, interference from the electronics, etc. The same with the AMPs.

When it comes down to onboard audio in modern high-end mobos, the DAC is actually pretty decent. I am not going to comment on every single measurement done to this Gigabyte Z390 Aorus mobo, but I will quote a comment about the DAC linearity: “This is stunningly accurate linearity which even expensive DACs struggle with at times”. Feel free to read all measurements in the link below.

The problem with onboard audio starts to show with the Amp. On a theoretical level, the onboard audio can actually produce more than enough power to drive high impedance headphones. The problem is the output impedance of the onboard audio is terribly high, so there is a lot of power loss. This will change the frequency response of most headphones, particularly those with low impedance (which is funny). And this is totally measurable and audible.

Julian gives a really good explanation about why a low output impedance is important, and how a high output impedance affects the tonality of a given headphone.

The bottom line is your onboard DAC is pretty decent, the amp isn’t. So just get a decent external amp and you can get away with that without the need for an external DAC. Keep in mind that the high output impedance of your mobo will affect more LOW impedance headphones.

That’s my two cents for the community.

EDITS:
A couple of important points from the feedback that I missed in the original post.

  1. Some motherboard manufacturers don’t have a proper implementation of the audio chipset shielding. That means you can get a lot of interference, particularly whilst gaming when your GPU is fully loaded.

  2. The front panel normally has a better shielding and amp solution compared to the back I/O of your motherboard. Connecting your headphone to the front panel is the best course of action if you don’t have a dedicated external DAC/AMP solution.

Additional links with measurements:

Measurements done in three X570 mobos from the well-known igorslab

Measurement on a MSI MPG Z390

PS: Thank you all for your feedback, questions, and insight.

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We need more well informed people in this hobby.

Can it though?
My thinking here goes like follows:
Unless you were to run DC-DC step-up for the audio circuit, you are limited to using the 12V to GND (-12V is technically available but reserved for the measurement circuits that keep the system alive).
So before losses, you get a power budget of 240mW into 600 Ohm (or ~500mW into 300 Ohm).

Big Assumption: Efficiency is similar to a Ti TPA6120a2
So under optimal conditions into a 300 Ohm load, you would get roughly 150mW into the headphones.

That may be fine when using very high sensitivities or when listening to very bandwidth limited music (maybe 8-bit music?), outside of that, I still would argue motherboards useable range tops out at 80 Ohm impedance headphones.

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Thanks @MazeFrame, I would go even further. We need more well-informed and educated people in general. The world would be a much better place.

Based on the measurements I’ve seen, the power loss is massive, and all independent measurements are very consistent in that regard. Actually, that estimation from that assumption is too good. I wish we could get 150mW into 300ohm cans. That would be very decent. A Schiit Hel measures around 200mW at the same resistance for example.

Yes, I totally agree, and at the same time, I would hardly recommend low impedance cans with such high output impedance. It would change the tonality of low impedance cans a lot.

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Neither the motherboard of my PC nor my laptop has a line out though, so would that mean you’d just put the system volume very low and connect the amp to the headphone jack of the motherboard?
On that note, the line out of my E10K that feeds into my Liquid Spark is pretty damn loud, so does that mean the Liquid Spark is not really amplifying anything at all?

This is my experience with the absurdly well praised LG phones DAC. I never found it that good when compared to even a 50$ dedicated dac/amp Fiio BTR3, because the AMP will shit its pants before you can even begin listening to the music. Use it as a source only, and it’s brilliant, but then what’s the point.

Makes me think it’s more of a gimmick just to brag on the spec sheets.

Correct, use the headphone jack of your mobo as a “line-out” and connect it to a decent amp. This is mentioned in one of the links I attached.

The signal coming out of your line-out in the E10K has NOT been amplified by the E10K, it most likely came pre-amplified. https://www.fiio.com/newsinfo/70577.html

Dude, the DAC on the LG phones is on par with a Schiit Magni 3, and way better than those from a high-end gaming motherboard. You would have to go way north of 200$ for a better DAC and I doubt there will be an audible difference, if any at all.

I’m not arguing the quality of the DAC, I said it myself it’s amazing as just a source. I’m just saying the AMP is so average, that it makes it a bit of a marketing gimmick, in my opinion.

Edit: I swear I read this exact phrase like 2 years ago before buying my LG phone:

“You would have to go way north of 200$ for a better DAC and I doubt there will be an audible difference, if any at all.”

yeah, honestly it would be really nice if the motherboard could properly drive all the high impedance headphones… would save me money for sure lol. amps and dacs do sound different and I can definitely tell when my signature changes in different ways depending on the hardware for sure… but the lesser units, like $100 range, barely change anything at all less comparing like… spark to atom

well, there is also the potential issue that the computer lacks proper shielding and what not on the board which will cause distortion, compression, buzz, etc forms of noise being fed through the just the amp with the pc as your dac… also, dacs like adi-2 over there and others also do change the frequency… though not as much as an amp admittedly. It is still nice to have a dedicated dac to clean up the signal if you ask me…

Personal anecdote:

When I had my motherboard out of my case after a construction related dust incident and all the covers and heatsinks removed, I noticed an NE5532 Op-Amp (very common audio op-Amp).
Turns out ASRock did not think much of the ALC1220 in terms of headphone driver and therefor included the 5532 for the front panel as headphone driver.
The Mainboard in question

@Cristian_Dobrescu sorry I misread your comment. I totally agree, what’s the point of having a really good DAC in your phone if the integrated amp can’t keep up? It defeats the purpose, and it’s used for marketing obviously.

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This is a really good point. I have experienced this myself with other high-end mobos that don’t implement their shielding properly (In some ITX mobos from the last gen, they have improved a lot lately since the whole “gaming” thing has scaled up quite a bit and the competition is fierce). Hell, there are some manufacturers that don’t do any shielding at all to the audio chipset.

Yes, especially if you need an amp anyways, you are better off getting a dedicated DAC too.

I will add this to the main post. I forgot to mention it and it is very important.

This is a very common practice, the amp solutions between the front panel and I/O panel (back panel) are totally independent of each other. Normally the front panel amp is better.

Igor mentions it in his article that I attached, I quote him “Almost all manufacturers (with very few exceptions) offer more power or higher voltage on the front panel. If you connect the headphones in the back, you’ve almost always lost. This is just a small reminder to those who have never thought about it before”

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Lg dac and amp are both fairly good. I wouldn’t put it up to he standards of stuff like standalone amps and dacs like the spark or even the implementation of the xduoo xd-05 plus. There’s a massive difference in body, tonality etc

This is true. I found the v30 to be very nice but with its amp it couldn’t power over 80 percent if not more of headphones that I wanted it to. Would do fairly well for the 58x but anything under a certain impedence and it wouldn’t make a difference