| Originally posted by jeremer@Jul 26 2005, 08:08 PM |
Very nice set up! How big is your ski hatch? I don't think my ski hatch is that big. Is your Rockford sub free air sub? and how do you mount it? Do you have any more pictures of the installation and detail wiring?
The Ski hatch in the E30 is the same as the E46. As SpOrky said though, that specific sub is not designed for free air, it did work OK though. The 15 is a lot, lot better. Whe choosing a sub for free air you need to look at the Theil Small Parameters. In particular the VAS rating. VAS is the Volume of Air Space required to produce the lowest resonant frequency (also known as Free Air Resonance, or Fs) to it's ideal effect. Look for a sub with a very high VAS, 150-300 liters is ideal for this application. Using a sub like the Rockford 10 in a small box is a good compromise. But it basically uses harmonics to fool you into thinking that the bass is deeper than it is. Regardless of the sub, the bigger the box, the lower the resonant frequency. My 15 pushes out 20hz with ease.
With regard to blowing the sub, it is unlikely, espectially with the 15. As the sub feeds directly into the cabin, once the volume starts to rise your hair starts to move, you can feel the bass in you chest, well everywhere actually. The sound pressure becomes too much for your ears to take and you have to turn it down.
Wiring is simple. The amp signal is fed from a tap into the rear speakers. The battery is in the trunk, and a feed comes from the head unit (which is stock by the way).
A bigger picture is attached so you can see it better