Re: HDC4s or HDDs
If you're gonna get 2, I'd go with a D1 to start, and run it at 2-ohms, that'd be plenty of power. Then get a second D1 for full 1 ohm power. Unless you have a really killer electrical setup to run a AQ3500 at .5.... If you are getting two, I'd pick the Tantric HD. The pair will be perfect on the AQ3500 at 1 ohm. And the one would be perfect at 2 ohms until you get the second.
If you're only gonna do 1 woofer, I'd go with the Tantric HDD. I still think it'd be best to go with a D1. Wire it at 2-ohms for daily, and .5 ohm for burps if you're competing. I don't think you'll notice much of a difference between 1 and 2 ohms daily, especially considering less voltage drop at 2 ohms.
2009 Hyundai Elantra - Budget Sound in Progress
HU- Kenwood eXcelon KDC-X994
Fronts- Crescendo MP6 mids, Vifa Ring Radiator tweets on Arc KS300.4
Subs- Single SA-10 on Mmats 2000.1 @ 1ohm
Misc- 1/0 CCA from AT, Big 3 in Stinger HPM, and AT 60 mil deadener
Bought from: Inferno333, select127, treesive, Kangaroux, DonH
Sold to: coolest user, Psychodrama, MidgetClown, mr.tigger, av83