For hardcore techno, your emphasis would pretty much be on the kick drum. So, with some EQ on the other tracks, you might be able to get away with just compressing the kick. Generally, for hardcore, I'm just compressing the kick drums. Just don't overdo it or you'll get a loud and flat sound. As for getting a fat and deep synth voice, that may not necesarilly be related to compression at all. That could be achieved with EQ and the stereo width.