Motherboard only has two AUX jacks - but website says it support 5.1

Question

It was kinda hard to google since most keywords are too common haha Sorry in advanced if it's common knoledge; Didn't had to work with other motherboards for about 7 years now

I'm about to buy a new computer and considering the Gigabyte Z790 Gaming X as a motherboard, but I am also using Logitech's 5.1 speakers set, which works fine with my current setup ( Gigabyte H170 Gaming 3 ).

The difference is that I need 3 outputs from the computer - which, right now, I have plenty - but somehow, the new MOBO only has two jacks and the website says it supports 5.1.

I read somewhere that I should connect the rear channel to my front output jack -- but that feels janky AF ( and also, require cable extender, and will make my table even messy-er than it is right now ).

Did someone encountered that with a modern MOBOs? Did you figure it out?

• I'm pretty sure the model of the speakers is z506, but it really doesn't matter - the connectors looks the same ( 3.5mm colored green, black and orange )
• I do not want to buy a PCI card for that.

Z790 Website H170 Website

Pictures for comparison:

Answer 1

I read somewhere that I should connect the rear channel to my front output jack -- but that feels janky AF (and also, require cable extender, and will make my table even messy-er than it is right now).

According to the manual, you are indeed supposed to retask the "front panel" audio jacks (a pin-header on the motherboard) for 5.1 and 7.1 setups.

Audio jacks natively support retasking in most HD-Audio chipsets (i.e. it is not something that only Gigabyte has decided to do), so the "Mic" input can be reconfigured as "Rear Stereo" output. Using the front-panel ones is a bit weird though.

To avoid the cabling mess, you could have the FP_AUDIO connector go to a backplate like this instead of the actual front-panel ports.

Answer 2

"Supports 5.1" - it probably does… just not over dedicated analogue outs without some re-jigging involving the front panel jacks too.

The HDMI, S/PDIF & USB, though, will support 5.1, with appropriate 'sound card' adaptor.
After comments:-
The 'computer' itself usually can't handle more than stereo because of licensing issues, so it is always handled in separate hardware - whether this is such as a built-in Realtek chip, or an external 'sound card' is actually irrelevant. All consumer audio is transmitted as 'stereo + metadata' from simple 5.1 right up to Dolby Atmos, the decode is done in the final hardware. This applies to USB, HDMI & S/PDIF.

Your simplest option is probably one of these adaptors - S/PDIF is probably going to cause the least amount of interference to your regular workflow - you won't need to specifically route anything to HDMI or USB, it should "just work".
They start for a couple of bucks/quid/euros on eBay - but avoid the very cheapest. By the time you reach $£€ 15-20 you will probably have something reasonably reliable.
The chipsets for these converters were perfected at least a decade ago, so they're cheap & common. I usually tell people to go for the first one they find that comes in a metal case. It seems as good a dividing line as any. They tend to use USB as a power source, with a cheap power-only cable supplied.

Here's one chosen almost at random by searching "USB SPDIF 7.1" on eBay - £15 UK. [Note they all tend to be 7.1 spec rather than 5.1. It makes no practical difference.]

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