Usually motherboards with on-board audio have three connectors on the motherboard: mic in, line in and speaker out. For motherboards with surround sound (4 channel, 6 channel or even 8 channel audio) more connectors are needed and these extra connectors are usually provided at an extra bracket that comes with the motherboard. Some manufacturers are putting these extra plugs on the motherboard instead of at an I/O bracket. This is done to help users.

click to enlarge
Figure 18: I/O Bracket containing extra audio connectors.

click to enlarge
Figure 19: Motherboard from EPoX where the manufacturer put all audio connectors directly on the motherboard, not required the bracket shown above.

Another audio option some motherboard models have is the SPDIF connector (digital audio). To learn more about this feature read our tutorial on the subject. As it happens with the standard analog connectors, SPDIF connectors can be available at an extra I/O bracket or can be available directly on the motherboard. The bracket shown on Figure 18 has SPDIF outputs (digital and coaxial). The motherboard on Figure 20 has already SPDIF connectors soldered to the board itself.

click to enlarge
Figure 20: Motherboard from EPoX with on-board SPDIF connectors (orange one and black squared with gray inside one).

The less brackets you have inside your computer, the better, because you will have better airflow inside your case, i.e. better cooling. That's why having all audio connectors soldered to the motherboard is interesting.