What are you using to trigger the compressor? I found from experience that its hard to get a good sidechain sound from linking it to your kick drum track because sometimes the sustain on the kick your using is too long in duration so the compressor attenuates the signal too long, the release is only...

Its just a normal crash with a long decay with the same crash sample but reversed just before it. End result is a smooth sweeping sound if you arrange the cross over point right