I know they are good subs. My wife has a 18" bl in her car. I had 2 15 BL's in my CRX. I have been just hearing a lot of the hdc3 and I might want to try them. I know that they like a higher tuning. But I built the box already for the BL's @ 33 hz.
I am really stuck and what subs to run.. 2 Audioque HDC312 or 2 Fi BL. I have a 4.0 cubic box after displacement and port area Its tunned to 33hz. I will be powering them with a Sundown SAZ-3000D. I can't make up my mind what I want to run