Seriously though, what kind of subs are you running? Are they in a sealed or ported enclosure?

I am running a pair of Diamond Audio dual voice coil 2-ohm speakers, connected in series for a 4-ohm load. They are in a common, sealed enclosure that is built into the sidewall of the rear of the station wagon (see attached picture). The volume of the box was as close as we could get to optimum, given the constraints of working with the shape of the car. It is probably about 20% larger than absolute optimum.

as you get into the higher frequencies, don't you start to get some serious directionality going on?

Some -- but not a lot. Remember, those subwoofers are about eight feet behind me, and low frequency sound isn't all that directional. I use the term low frequency somewhat loosely here -- 900 Hz isn't all that low. But when you consider that the front stage is sometimes producing sound at twenty times that frequency, that may put it into perspective a bit better. Perhaps another contributing factor is that the subwoofers are not pointed towards the front of the car -- they are pointed sideways across the back of the car, and reflect off the windows a few times before arriving at the listening position. This would tend to further degrade directionality. I lose more imaging, I think, from the two 6.5" speakers back in the roof than I do from the subwoofers.

Perhaps the most persuasive argument I can make is purely anecdotal: I had to stop telling the IASCA judges how I was crossing over my subs, otherwise they scored me on what they thought they should be hearing, instead of what was actually there. When I kept them ignorant, my scores were quite respectable. Another anecdotal example: This will sound like I am bragging, but remember, I am a medium sized fish in a very small pond here in Alaska. Just about everybody who has listened to my system says it is the best they have ever heard, and not a single person has ever thought it sounded better with the subwoofers crossed over at a low frequency. About 80% of the people who hear it will use the words "clear" or "clean", completely unprompted, sometime in the first 20 seconds. Now, keep in mind that a system that is really outstanding in Alaska would probably be considered good but not all that special somewhere like Los Angeles. I wouldn't win any prizes competing there -- but I wouldn't be embarassed, either.

tanstaafl.