IE....i set my HU sub setting to 125 hz and under....i set the amp to 80 hz and under....what will the subs hit....which source do they "listen" to...I'm guessing the amp but please correct me
Well they sort of work with each other. The HU will send out the signal with freqs below 125Hz, then the amp will take this then again filter it to leave the freqs below 80Hz.
If they were set the other way around, with the HU at 80 and the amp at 125, then the HU will filter all freqs above 80Hz, and the amp will have nothing left to filter since all freqs it has recieved are already below its own cut off freq.
The head unit takes priority over the amplifier.Whatever signal you feed the amp the amp can only play that signal.You can of course fine tune it through the amplifier.
Only thing you need to worry about is what slope you'll end up seeing if they're different on the HU & the amp.
IMO its always easier to use the HU (since it's a simple adjustment anytime you want...I sure as hell am going to avoid taking my rear seat out to change the xover freq.)
