How to Make Chords Drops? (liquid/melodic dubstep)

Hi I was wandering if anyone knows how to make ‘chord drops’ for liquid dubstep style songs (I’m not sure what its actually called but it does sound like a chord) for example this drop that occurs @ 1:35 in this song : br
iframe width=“560” height=“315” src=“//www.youtube.com/embed/09wdQP1FFR0” frameborder=“0” allowfullscreen/iframebr
or this that occurs @ 3:15 in this song :br
iframe width=“560” height=“315” src=“//www.youtube.com/embed/lSooYPG-5Rg” frameborder=“0” allowfullscreen/iframebr
thank you in advance =D,br
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-Devon