A sampler is a very open-ended tool for creating and making music, practically all hip-hop is sampler-based music. Basically, there are two types of samples: loops and "one shots". One shots could be sounds like sound effects or flourishes. Loops are rhythmic samples that are meant to be played continuously (looped) in time with the song. Drum loops are common of course, but any musical phrase can be looped...drums, keys, guitars, vocals, whatever... A lot of possibilities to fill out the sound of your band.
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