If your not doing coaxials your always best to place the mid on top of the tweeter, you should also space the tweeter back so that the voice coil of the mid lines up with the voice coil of the tweeter.

The tweeter's placement is always more critcial then the mids, most mids have better off axis responce then tweeters. I would start with the tweeters and play with the angles till you have the image and stage you are looking for.

 

As the guy from ING would say "I couldn't have said it better myself".

Especially aligning the voice coils to eliminate/minimize pathlenght diffs....

 

I am confused by this. A good crossover
would make up for the different acoustical centers.
From what I gather, aligning acoustical isnt nessecary. But i dont know if that applies to a car since most installs will have the speakers mounted in strange ways.

[ January 28, 2004, 10:19 PM: Message edited by: Seahag ]

 

Can you explain what you mean ?

 

Crap! me explaine something.
I read an artical about crossover design, they compared 1st 2nd 4th order crossovers.
all topologies were compared with
acoustical centers aligned, flush mounted, and driver behind (just for arguments sake)

The one that sumed flat over the xover point was higher order slopes and flush mointed drivers --> meaning offset.

I am not saying I agree or disagree, I am just confused.

Phase is a funny thing.


Interesting reading ..


http://www.geocities.com/kreskovs/TimeAligned2.html

http://www.sound.westhost.com/ptd.htm

dry reading warning

[ January 28, 2004, 10:39 PM: Message edited by: Seahag ]

 

Utilizing higher order filters allows x-over points closer together for each respective driver, and takes so of the guesswork out of it, or at least easier.

For Example, if you were utilizing 12 dB/Octave slopes your midrange lowpass might be at 2500Hz and your tweeter highpass might be at 3500 Hz, a significant underlap. As the slopes are more gradual you would endeavour to have the summed output at for example between 2500 and 3500 Hz to be flat with the rest of the response curve. You will end up playing around quite a bit to see which frequencies sum up flattest.

Now if you were utilizing 24 dB/Octave slopes you might x-over the mid low pass at 2800 Hz and the tweet at 3000-3200 Hz, a much smaller gap, and hopefully a lot less monkeying around as you don't have to rely so much on what the summed output will end up as. Instead you assign a frequency set to a driver and cut it off sharply, then have the othet driver pick up from there. Less overlap, less variables, less problems, less tuning time (hopefully).

 

Here are a few things also to add about kicks. If you have a fairly large dash overhang and/or a big center console you may have issues of not being able to get the sound “out” from under the dash in the lower mid-range and mid bass. There may also be some cancellations just totally messing up things. There’s a few things that can help out. One thing that some people do is build under dash mats. But now the trick is to stuff the “inside” of your dash with an absorbing material and make a permeable “soft material” grill to go under the dash. This will better absorb the lower frequency stuff that may be bouncing around. The other thing is to get a set of tweeters in the A-pillars or even do what I did and put both the tweeter and the mid up in the A-pillars. I put a small mid up there and then run an 8” midbass in the doors. So far it’s working nicely. I was having huge sound issues with kick panels in my truck. I don’t even want to talk about how many sets of kick panels I built and how much material ended up in the trash. The environmentalists would go nutz to hear how much fiberglass I contributed to the local dump.

Tweeters are very directional. Basically with tweeters, you are playing with angles. Distances are not so critical as in the midbass frequencies where PLD’s are very important. The mid range driver/midbass driver is the most critical to setup properly and also the hardest one to do, especially in the lower frequency ranges that it covers. It’s a combination of angles and distances and is not always and easy thing to figure out. Many higher end system designers will spend days building many sets of kicks trying to find the magical ones that work. Or you can get part of the way there and then process the crap out of the signals to fix them !!! Many wanna-be purists are against this but I’ve yet to hear many cars that achieve this goal. But’s their’s tons of people yappin’ about processing and how you’re from the dark side of the force if you use it.

 

Point source speakers do have significant cons. Sometimes you want to angle the mid-woofer and the tweeter differently to get your desired sound.

Aside from the slope differences between passive x-overs, most coaxials/point source speakers only have 6db/oct crossovers, that usually places the tweeter and the midwoofer out of phase.

I guess patience is the name of the game when it comes to kicks. Good luck! [img]graemlins/thumb.gif[/img]

 

Tom, your post reads like a carsound.com bible....Lol!!

 

Tom, I'll be taking a 1/2" drill bit, and punching 600 holes in the bottom of my dash. Then I'm going to stuff 345 MAXI pads inside of the dash cavity, that should help "abosorb" stuff. And I'll even keep a few extra in the glove box!


Ghetto Adam