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For those that want to accomplish good imaging in a car, here is a relatively simple method brought to you courtesy of Image Dynamics:

"I learned this from one of the top installers in the world, a good buddy of mine.

1) Put your front seats where you intend to either drive the car or where you will have them if you plan to compete, this is very very important. I am talking about fore and aft, height, seat back tilt angle. If not competing then where you will drive the car at and the passenger side the same.
If you are competing in car audio comps, then all the way back and low but even with the passenger side for height, lean the seats back a bit but not real far to make them uncomfortable.

2) Sit in your seat as you would driving or listening as per above, make sure you are correctly placed, if you tend to drive leaning way forward like some do, you should adjust how you sit, better for your posture anyway, lol, lean back in the seat :)

3) Have somebody you trust to do this correctly, critically important. Roll the windows up, have them look very very carefully at where the entrance to your eardrum is on your window side ear, left ear, mark it on the window or on the pillar with a small spot of tape.

4) Move to the other front seat and do the same except of course on the right ear this time.

5) Ok to get out of the car now Measure 5" forward and 1.5" down from the spot marked for your ear entrance points on each side of the car, should be two marks on the car now, one for your ears and one forward and down as above.

6) Build some temp baffles for the speakers or the ones you will use, what I do. Have the tweeters mounted very low and to the door side of the baffle, the woofers go furthest forward and low as well.

7) Aim the woofers(midbasses) exactly at the forward and down spot on the glass you marked.
This is the sweet spot, instead of fighting the glass reflections you are using them to your advantage. The right speaker will reflect off the left glass into your left ear and help equalize the sound you hear from both speakers, seems odd but it works, exceptionally well. I beat a prior world champ twice in two months, two seperate installs in my truck and two totally seperate comp installs in his truck and a customers truck using these methods of alignment.

8)Take a kitchen towel and put it behind the baffels can cover the back of the speakers, then do some serious listening tests to see if you need to align them differently but this should be pretty darn accurate.

9) Be very carefull when glassing the kicks as the glass can pull them out of alignment when drying as tends to shrink so mount the baffles very well before glassing.

10) Wire the midbass on the passenger out of phase with the drivers side midbass, you may lose some midbass output but the sub can help make up for that quite well when tuned properly, better yet to have some midbasses in the doors. Try all the phasing setups you can, sometimes the drivers side is best, sometimes but not often, both in phase works


For those not building kicks here is a simple install plan that works quite well, has been used alot in competion cars.

1) use the door locations for the midbasses, both in phase.
2) tweeters in the A pillars firing directly at each other, as wide apart as possible, both at the same exact height and about 2" above the highest point on the dash. Wire both tweeters out of phase(pos and neg wires reversed but this may have to be reconsideded depending on the midbass wiring, take your timem and try them all! Make sure to try many different aim points as well.
3) Use a dash mat, fugly but they work.

In fact, a dash mat will improve just about any install ever done, including kick panels, have one in my truck, been there for years"

im gonna have to try that on my mazda or my mustang when i get a few hours of time to mess around. sounds like it will work great. whats the reason for wireing the mid out of phase?

sinister audio wrote:im gonna have to try that on my mazda or my mustang when i get a few hours of time to mess around. sounds like it will work great. whats the reason for wireing the mid out of phase?

Can potentially help get your imaging right. Basically messing with acoustic phase to try to offset the pathlength differences you have in a car.

Hmm...

This is an intersting strategy, but for my own personal tastes, it's a bit too "general rule of thumb" to me - there's a LOT more going on in a car, than would yield this "one winning formula".

Jonathan wrote:Can potentially help get your imaging right. Basically messing with acoustic phase to try to offset the pathlength differences you have in a car.

Issues like these are what are REALLY being dealt with.

I could think of one very simple thing that would blow that first post right out of the water - the center console.
It's that simple.

Take two cars - one with no center console to speak of, and one with a big, tall center console - maybe a Subaru B9 Tribeca, for example?

Set them both up using this "rule of thumb".

I guarantee you, they won't sound the same.

In fact, I'd be surprised if you would be satisfied with both vehicles, much less having them represent an "ideal".

Oh- also, wiring out of phase can cause as many issues (typically more) as it might help - it's not just a tweaky-geek sort of thing either - but the problem is you have one speaker playing a broad range of frequencies, all of them having different wavelengths - but playing to your ear along a pathlength of an unchanging distance.

Wiring out of phase can result in those longer-wavelength signals simply cancelling each other out - progressively more so, as wavelengths get longer- Eventually you get to a point where the wavelengths are so much longer than your pathlengths to your ear, that you actually do get pure cancellation - what sound remnants you are left with can be artifacts of reflections and other non-direct sound!

It's something that's fun to play with, to see where it helps, and learn where it hurts - but I personally wouldn't ever feel comfortable advising someone as a "rule of thumb" for an improvement - it's one thing to play with it, but that suggestion for playing needs to come along with a big disclaimer - something along the lines of "you may kill your midbass - something you might not even be happy enough with now - or create other phasing gremlins, in fact you are more likely to go back to "in phase" in the end"

I did an article on absolute (as received as your ears) sound, focusing primarily on absolute phase:
http://www.betteraudio.com/geolemon/phasing/phasing.htm

[quote="geolemon"]Hmm...
This is an intersting strategy, but for my own personal tastes, it's a bit too "general rule of thumb" to me - there's a LOT more going on in a car, than would yield this "one winning formula". ]

Yeah, the good ol' center consoles are a PITA. Non-symmetric, curvy, oddball shaped dashes are too.

The tutorial is more a starting point than anything, if you put some plumbers strap on the baffle and work on focusing you can improve it. I think it's also important to note that Image Dynamics is most successful (and competes most) in classes that require 2 seat judging, and this tutorial is catered more to that. After all, most of them are horn cars. If you're only going for one seat, you can get good results just with time/phase alignment.