Help needed with "In Car" Measurements

[dawaro]

I need to pick the brains of the group a little and see what you all would think would be the best approach at designing a passive system for car audio use. I have a friend that is in the process of building a show car out of a 90's model Mustang. While the primary focus is going to be around the engine performance he still wants to have a nice stereo system in it.

We have looked at a lot of offerings from various manufacturers for the upper end and I have yet to find something that looks like it is worth the money. Some of the component sets we have looked at are in excess of $600. To me that is outrageous. My thought was to actually take in car measurements and build our own passive xovers. I cant see how we cannot exceed the performance of any of the standard component sets and their generic xovers. Which brings me to my question, what would be the best way to take the measurements? The speakers will all be mounted in the door panels. Due to clutch requirements and aftermarket computers the kick panels are out of the question. My thought was to place the mic at ear level in the center of the front seats and take the measurements from there. Does this sound like a good approach or is there a better way of doing it?

[Nat Ward]

I don't see why you'd want to put the time and effort into building a passive system when you can find a good number of headunits that will allow crossover/time alignment etc actively. That's what I'm doing right now using an Alpine 9833. Can't remember rules about posting links to other forums - do a internet search for do it yourself mobile audio - tons of good info over there. If you want some more info feel free to email me at njw108@hotmail.com.

[joecarrow]

I must say, I have to agree with Nat. I don't know a whole lot about car audio- this is a more home-audio oriented forum afterall- but I do know that some of the chief drawbacks of an inexpensive active crossover is a poor signal to noise ratio, some additional distortion to the pre-amplifier signal, and the need for multiple amplifiers.

The signal to noise ratio is less of a concern in a car because you already have so much road noise. Whether the noise floor is 60 or 120 db down, you're unlikely to hear the difference when you're hearing 50+ db of road and engine noise. This will also help mask the low level of distortion from the active crossover. Overall, these pre-made active crossover head units with amplifiers built in look ideal for high quality work in a car environment.

[Finleyville]

Some very good reading on DIYmobileaudio.com. In fact, you could lose years in researching that site. I know I have! And the best part is that most of it IS DIY. Good luck.