DIN
Stands for German Industrial Standard and describes a standard dash slot for a head unit or a multi-pin connector used in instead of a RCA connector

DSP
Digital Sound (Signal) Processor - essentially a graphic equaliser with presets, which allows the user to programme particular tonal presets

Hertz
The measurement of frequency, usually written as Hz or kHz (kilohertz)

MDF
Medium Density Fibreboard - used for building bass enclosures and the like

RCA jacks
The coaxial connectors used to link components

SPL
Sound Pressure Level - the amount of volume produced in decibels

Staging
The direction that the listener believes the sound is coming from