Difference between "rear" audio and "line out"

Question

My Z370-E motherboard has a black (labeled "rear") and green ("line out") audio output. See the image below (image credit Kit Guru).

I can use both with my headphones, but it isn't clear to me what the difference between them is. So what is the difference and when or for which devices should I use which port?

Solution

Your computer has a standard 5.1 surround soundcard on-board. This means that, in order to drive all 6 channels, you need 6/2=3 connectors.

• Green is the default stereo channel for front-left and front-right.
• Orange is the default sub+mid channel, sending audio to the subwoofer and the front-mid channel.
• Black is the default stereo rear channel for rear-left and rear-right.

Some onboard soundcards will send stereo output to the rear channel in case no connector is connected to the proper green connector. Other soundcards may simply up-mix the stereo sound to all channels to make the stereo sound come through all speakers.

The difference will be noticeable when you connect a 5.1 surround speakerset and you use/play a surround demo/movie. Then the rear channels will be mostly muted or have a lower volume in order to be able to get those channels played when audio comes from that direction.

Just for reference, the blue and purple connectors are input connectors, not output connectors. They are line-in and mic.

Comments

[Moab]

See this>>>>>>>>>hobby-hour.com/electronics/sound-card-color-cod‌​e.php

[Moab]

Here is your motherboard manual also>>>>>asus.com/us/Motherboards/ROG-STRIX-Z370-E-GAMING/…

[Bram Vanroy]

So if I understand correctly: when connecting a regular stereo device, just connect to the green connector. For a 2.1 this might be the green and orange. And 5.1 green, black, orange. Is that correct? I was confused because I didn't know that "rear" meant "audio of rear channel". I thought it just meant "audio port at the rear of the PC". Oops.

[LPChip]

Yes, that is exactly what it means.

[ThrowableException]

so If I just want to connect my headphone which has just one 3.5mm jack, I can connect to either read speaker(black) or Subwoofer (orange) ?

[LPChip]

@ThrowableException no, you can connect it, but it will sound off if the green is also connected. Also, keep in mind that the lineout is not amplified while a headphone jack is, so it is going to sound soft regardless.