I can understand if installers aren't comfortable giving you technical advice. An enthusiast your age talking at the beginner level about six 18" subs and a Rockford T40001bd would cause me to worry a bit. They're probably mostly surprised because young installers don't know about us old hardcore dudes. But my concern is that you're considering an amplifier that if not installed correctly, has the potential of burning your car to the ground. Plus, you will need to upgrade your charging system, alternator and use some serious termination skills, according to what I interpret from the Rockford website. A pro installer would be more likely to walk into a biker bar wearing a ballet outfit than to lead you into destruction!
I can see some serious design conflicts just by looking at your product selections. For example, USD A-700 waveguides are midrange emitters, so you don't need more mids to go with them. The recommended crossover point is 800Hz, so your system should really look like two subs, two midbass drivers and two waveguides if you were looking at a sound quality competition system. With six subs, you will have nearly 1,600in2 of cone area driven by 4,000 watts, so you won't likely hear anything but bass. Also, the musical preferences you mention lead me to believe you won't be listening to high-quality audiophile software, so the waveguides are probably going to be the first things to blow. Another problem is trying to hit 155dB without the goal being competition. You can do it, but it won't sound good and would be a waste under any conditions other than competing.
In essence, you're mixing sound competition quality horns, subs worthy of a Montreal disco and an amplifier capable of arc welding. I'm also mentally trying to recall how many vehicles will accept four 18" subs and their required cabinets. Match this with some of my personal favorite head banger music and I don't really understand where you're trying to go with this design. Your best course of action would be to enlist the services of a trained installer who can help you design and execute your project. You will learn a lot from the process while having fun, and it will probably even cost you less in the long run!
Q: Hi. I live in New York and since it's been cold I'm unable to work on my car. Because of that, I started researching how to make my sound quality car better than my friend's so that I can beat him at next year's shows. Right now I have a pretty simple setup and after doing some research I came up with a couple of questions.
First of all, I'd like to know your stance on 3-way setups? I was thinking four 8" midbass drivers in the doors running below 200Hz so that it doesn't affect staging and pull the image down to their location. Midrange would be 4" speakers in the kick panels and of course tweeters either up on A-pillars or up on the doors.
My second question is which way do you think is better to mount midrange speakers: pointing at the ear of the driver or to the middle of the car? And, will I need to point my tweeters in the same direction as the midrange?Thank you very much,
Aleksandr Repnoy
Schenectady, NY
P.S. Car Audio and Electronics rrruuullleeesss!!!
A: First off, the philosophy for SPL is "more is better" and for sound quality is "less is better." My ideal SQ system would consist of a pair of 10" or 12" woofers and a pair of big, fat, syrupy soft-dome tweeters. That's all. In a way, it matches my 2-channel home audio system, which uses 2-way Magneplanars driven by a vacuum tube amplifier. By having less individual speaker elements, I'd have less phase problems and localization miscues, but let's talk reality: To get this to work in a car, I'd need to mount the woofers and tweeters in the front of the vehicle, and my biggest problem will be shoehorning 10" drivers into the footwells.
So, we got nowhere before the compromises started. I can downsize my woofers to 7" or 8" units, if I add a single or dual subwoofer in the back. That's not a problem, and I haven't deviated enough from simple to cause sonic discord.
My next concern is between the woofer and tweeter. First, they must both have good frequency characteristics at the crossover point so the handoff between the two isn't an abrupt difference in sonic character. Second, they must be mounted as close as possible together to prevent "frequency dependent shift." This happens when a singer reaches a high enough note that the work is now shifted from the woofer to the tweeter. If the tweeters are not near the woofers, I can expect to notice that the singer appears to be darting around on the stage - not good. For a crossover point of 800Hz, the maximum distance apart is about 4" from the center of the woofer to the center of the tweeter.
Take my example and see if you can make your design match the core idea. And if you travel up to the Toronto area, stop in at the school so I can see how it came out!