This applies to the Scarlett, Saffire, iTrack and Clarett Range
Direct monitoring allows you to listen to the input signal of the interface with near-zero latency.
It takes the input signal on the interface and sends it straight to the headphone and line outputs on the device. The signal is still sent to your DAW software allowing the input to be recorded at the same time.
If, when recording, you find there is latency or "delay" on the signal you are monitoring, you should switch on the direct monitoring on the interface and then mute the audio track that you are recording to. This allows you to hear your backing track, for example, from your recording software as well as your input signal at the same time, with near-zero latency.
See this article for details on how to use the Direct Monitor switch with Scarlett Solo, Scarlett 2i2 and iTrack Solo.
See this article for details on how to use the Direct Monitor dial with Scarlett 2i4.
For all other units please view the product user guide, available from the Downloads section of our website.