Some drum controllers have sounds built into them, others are just triggering devices which need to be hooked to a synthesizer or tone module. Drum Machine A smallish box with buttons on the front which correspond to drum and percussion sounds stored in it's computer memory. Drum machines have small sequencers in them which allow you to record musical patterns into it's memory. A memory storage device now common to all computers. Your hard drive is like the file cabinet next to your desk - you can store a lot of information there, but when you want to work on a project, you have to pull it out of your file cabinet and put it on top of your desk.
Some synthesizers have small hardware sequencers built in.
Hardware sequencers have the advantage of being more portable. Strip Common box which plugs into an AC outlet and provides 4-6 extension outlets. Also called a power strip. Also called a junction strip. An acronym which stands for Musical Instrument Digital Interface.