Why I think the onboard sound on many motherboards is bad or at least not optimal, I would like to explain in detail in this analysis. The usual tests (and marketing) usually focus only on the DAC and the codecs, but eggs the actual problem smoothly. What do good headphones, a potent graphics card, a medium-priced motherboard, an oscillograph, a very good multimeter and a set of trained ears have to do with each other? Let's find out!
And something else before I start. The msI Z370 Gaming Pro Carbon motherboard used here isn't even bad, quite the opposite. It is one of the better ones and is in the VGA test system for 2018/2019. There are even more extreme motherboards, right down to the extra-nasty audio complete deniers, usually from the 100-euro shelf (and below). But if even such a motherboard, such as the one used for this test, cannot really convince, how cruel must the reality of the cheap homes be?
Sure, there are also motherboards e.g. with an ESS SABRE 9218, which is supposed to deliver 2 Vrms at the copphone output (e.g. on an Aorus X299 Master), but these are unfortunately real exceptions. But as already teased – the levels are unfortunately not everything on their own. And also ESS unfortunately does not write which impedance the 2 Vrms will be in. But I'll definitely find out in the next test, because a "up to" is more spongy than Sponge Bob after 2 hours of dishwasher.
What this article offers and what questions it answers:
- Analysis of the maximum possible output level ("volume")
- Why not every headphone sounds like or is as loud as you'd like
- Where the annoying noises (also on the desktop) e.g. come here while scrolling
- Why powerful graphics cards under the load of gaming can further distort the sound
- How to break this knot
What this article does not want to offer:
- Voodoo about expensive DACs and Japanese precious capacitors
- Advertising of overpriced sound solutions and gold cables
- Professorial tech chatter from the ivory tower of the audiophile substitute religion
The reasons for this article
There are a lot of good reviews about the onboard sound and even blind tests that prove (want) that it doesn't always have to be the overpriced sound solution that seems necessary for daily happiness or is propagated as such at least mantra-like. However, almost all tests generally go wrong: you play music without processor and graphics card usage and assess a state that, for example, is a state that is will never occur in gaming.
Also, with smooth classical sound in such a test, no one will scroll back, down, up and down on the screen. This is far from practical and actually only proves that the DACs (digital-to-analog converter) of current motherboards are now better than their reputation. The problem, however, is that the digital part has long since ceased to be a weak point, but that the analog branch, including all signal paths on the motherboard, is the actual bottleneck.
Apart from the fact that the effective voltage (Vrms, I'll explain) for the clean control of the headphones is far too low on almost all motherboards, the "insilates" (interferences, transients) by a potent graphics hardware are a real Vulnerability, because the EMC tests and the CE certificates issued concern the GHz range, but not what ends up in our ears as mixed-together frequency waste. Often enough you can hear what you see, unfortunately.
Without becoming too technical now: at the nonlinearities of many amplifier units, mixed products are created from various signals, direct and indirect, because every non-shielded, metallic surface simultaneously acts like a small antenna. There is straightened and intermodulated until the doctor comes. Don't you think so? This can be measured and proven. Even where inexperienced ears can't or don't want to notice anything.
In addition, you operate (often without knowing it) your headphones at the audio output of your motherboard far below value! I have therefore inserted an extra chapter that deals specifically with it. After all, full control, over-control, distortions ("clirr") or the still (subjectively) cleanly achieved maximum level as acoustic added value are a really gloomy onboard chapter in itself.
And often enough, either headphones are stamped as cucumbers, even though only the motherboard doesn't play, or their "bad and unclean" sound criticizes, just because distortions that start far too early negatively affect the sound. Mr. and Mrs. Gamer like it loudly, but that's exactly what almost all onboard solutions fail to do. The beauty of this is that this too can be easily measured and proven.
Measurement structure and tests
Since we have to concentrate on two completely independent topics, I also divide this article into individual thematic areas, which are then based on different individual measurements and analyses. In detail, this will be the case:
- Measurement of maximum achievable output voltages at 32 and 500 ohms (Vrms) for volume and headphone assessment
- Measurement of interference voltages at different graphic loads and output impedances
- Detailed analysis of interference voltages with various graphics cards
- Comparison of analog and digital outputs with separate sound solutions
I measure the output voltages in general with the high-resolution oscillographer, but also do the necessary plausibility checks with the memory multimeter before each run. The beauty of this multimeter is e.g. the very high sensitivity and the possibility to determine and precisely control frequencies of the measured alternating voltages. At the output, I use only ohmic loads in the simplified measurement setup, thus closing the output of the sound solutions with a 32 or 500 ohm resistance. Open-running exits would be rather unpractical and therefore pointless.
The low-impedance measurements are interesting when it comes to mainstream headphones with impedances between 16 and 50 ohms, the other measurements with the closing resistance of 500 ohms are important for connecting external speaker systems (analog input) or high-impedance headphones with impedances between 250 and 600 ohms. Because they are also available (not only, but above all) in the professional environment (then quite frequently).
The actual VGA test system remains unchanged and I have already described it in great detail in the basic article "How We Test Graphics Cards" (English: "How We Test Graphics Cards"). For the sake of simplicity, therefore, I am now only referring to this detailed description. So if you would like to read all the relevant information in detail, you are welcome to do so. But there is something going on here about the audio theme.
If you are interested, the summary in table form quickly provides a brief overview:
|Test systems and measuring rooms|
||Intel Core i7-8700K x 5 GHz
MSI Z370 Gaming Pro Carbon AC
16GB KFA2 DDR4 4000 Hall of Fame
1x 1 TByte Toshiba OCZ RD400 (M.2, System SSD)
2x 960 GByte Toshiba OCZ TR150 (Storage, Images)
Be Quiet Dark Power Pro 11, 850-watt power supply
|Graphics card||Nvidia RTX 2080 Ti Founders Edition|
||Alphacool Ice Block XPX
5x Be Quiet! Silent Wings 3 PWM (Closed Case Simulation)
||Lian Li PC-T70 with expansion kit and modifications
|Sound solutions:||Onboard sound of the motherboard
Asus Xonar Essence STU
Creative Sound Blaster X AE-5
||Direct voltage measurement at the audio outputs
1x Rohde & Black HMO 3054, 500 MHz multi-channel oscillograph with memory function
1x Rohde & Schwarz HZ355, probe divider (10:1, 500 MHz)
1x Rohde & Schwarz HMC 8012, digital multimeter with storage function
|Operating system||Windows 10 Pro (1809, all updates)|