Analog output of sound card is connector pass signal in analog ("as into nature") form to amplifier or active speakers (speakers with built-in amplifier).
The beginning of articles about sound cards here...
1. Line output is sound card out with signals standard level (250 mV).
Usually sound card has two mono line outputs (used as stereo) or one stereo.
For playback 5.1 and 7.1 records some cards have 6 to 8 ouputs (include LFE/subwoofer output).
2. Monitor output is linear output for:
- headphones (in recording workflow) or
- studio monitors (for music production) or
- stage monitors (for live concerts).
At concert line outputs of audio card are connected to loudspeakers directed to listeners. It is desirable to have additional monitor outputs to output the sound to stage monitors: musicians are well heard that they play. More right use external mixer with monitor outputs.
You can use monitor outputs in home recording studio (without external hardware mixer).
3. INSERT (output and input simultaneoustly) is a point of connection to external hardware audio devices (reverb, vocal and guitar processors, etc.).
Insert is a union:
- output (from card) to external processing unit (signal before processing)
- input (to card) from the unit (already processed signal).
stereo (two mono) INSERT connectors (1 mono processor to each mono channel)
Connecting audio processor to sound card
For each channel we use 1 stereo jack connector.
Stereo jack is connector for INSERT input/output
Usually USB, FireWire-sound cards, sound cards, or PCI with external modules has connection points INSERT.
Through this point the sound:
- coming (from INSERT output) to an external processing unit,
- passes through the unit
- back (to INSERT input) to sound card.
Read what is digital input, digital output here...