I am really wondering how the artist of this track made such a clear "trumpet" drop.
Could someone please explain how this could be reproduced with Sylenth1, Spire or any other Synthesizer.
Since this is a sample, it will be difficult to re-create with any synthesizer. To me it sounds like a baritone saxophone playing high notes. You can look for free sax samples and load them into a sampling program, or find a sax VST. As for how to make it "clear", start with a good sample and apply the common production techniques (EQ, slight sidechain compression, etc).