I have a sundown 1000D running a 12 inch sub wired to 1 ohm. It's all hooked up but the LP x-over seems to have little effect on the speaker frequency output. I can hear voices and it sounds full range no matter where I put the setting. I hooked the sub up to my comp amp and the LP worked fine. I would normally consider it a defective amp but I had the same problem with another arc amp I had and it seems too coincidental. I'm using an Alpine 9553 HU. I'm trying to think of anything else to try before I have to send it back. Any ideas?