Is it preferred to hook up a single powered subwoofer by going directly from the 'sub out' on my mixer directly to the sub and straight from the Main outs on the mixer to the tops,or go straight from the Main Outs on mixer into the sub xlr IN, through the sub x-over(80/120) and then from sub OUT to the tops?. My mixer has a 1/4" sub out with small frequency dial (40-200hz),but not sure of the 'proper' way to hook up?! Thanks,Huck