High level means your amps are putting out the signal for under 20hz....IMHO and IME all amps sound better when not driven to the lowest. I would recommend using low level inputs and dumping the lowest freq. off from your full range amps.
Some subs have a line level XOver...I had very good results with Passive Line Level Xover, say from 50hz up!
You will win a lot of detail and dynamics on the mids and higher freq.
IMHO that is the most important feature of a subwoofer, leaving the lowest Freq. to a speialized sytem (the sub) in order to allow your full range system to breath better on top!
Some subs have a line level XOver...I had very good results with Passive Line Level Xover, say from 50hz up!
You will win a lot of detail and dynamics on the mids and higher freq.
IMHO that is the most important feature of a subwoofer, leaving the lowest Freq. to a speialized sytem (the sub) in order to allow your full range system to breath better on top!