I have done this, where you double the tempo before...and it can definitely sound good. For example mixing hip-hop (90-100 bpm) and drum and bass (180-200 bpm) I used to do it a bunch. And it sounded good.

HOWEVER, 144-180, matching every fourth beat as the original poster said, would not work. The phrases would conflict. It might sound good if one of the tracks was either just beginning or just ending and was solely a kick beat and nothing else, but even then it'd be really weird. Maybe it wouldn't be too bad if you mixed very quickly and didn't leave both playing for long...but still.

I would definitely try it and see for yourself, but as I said originally - this will sound really strange.

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-Jon
www.DJjoncaserta.com - - mixes and whatnot (melodic progressive house and trance)