| ADC | Analogue-to-digital converter. Converts analogue audio into digital audio. |
| Buffer size | The number of audio samples held for processing before the audio is passed on. Lower values reduce latency but increase processing demand. |
| DAC | Digital-to-analogue converter. Converts digital audio into analogue audio for outputs. |
| DAW | Digital Audio Workstation: software used to record, edit and mix audio. |
| dB | Decibel, a unit used to express a level or level difference. |
| dBFS | Decibels relative to digital full scale. 0 dBFS is the maximum digital level. |
| dBu | An analogue audio-level unit referenced to 0.775 V RMS. |
| DI | Direct/instrument input. On iD4 MKII this is the front-panel JFET instrument input. |
| JFET | Junction Field Effect Transistor. The type of input stage used for the iD4 MKII instrument input. |
| Latency | The delay introduced while audio is converted, buffered or processed. |
| Loopback | Routing audio from iD4 MKII/computer playback back into a recording or streaming application. |
| Monitor Mix | The hardware control used to blend iD4 MKII's direct input signals with DAW playback. |
| Phantom power | DC power supplied through an XLR microphone connection when required by the connected microphone. |
| ScrollControl | iD4 MKII mode that allows the main encoder to act as a virtual scroll wheel for compatible software controls. |
| TRS | Tip-ring-sleeve connector. Used for balanced line connections or stereo headphone connections depending on the socket. |
| USB | Universal Serial Bus. iD4 MKII uses USB for power and audio communication with the host device. |
| XLR | A three-pin connector commonly used for balanced microphone connections. |