Really? When you said that your hd3 wasnt spectacular, was it off of that 1.5ft^3 box also? Nice that your giving it so much juice //content.invisioncic.com/y282845/emoticons/fro.gif.c695f1f814b01c4ad99fe7f8cccadd29.gifHD3 I have my single 12 in 1.5cubes tuned at 40hz and about 3500rms (4k+) on tap and it sounds amazing I will take a vid soon, but there are already plenty of you tube vids on hd3 woofers watch some of them. An last 36-40hz is where you want to stay on an hd3. My single 15 sounded good at 36hz with 3k if that helps any, and good luck with your purchase.