help to figure out X-over points and gain

I have 4 pairs of speakers plus my subs that I need to manually X-over. Im using a symmetry to set the X-over points. Is there a FAQ on how to figure out at what freq points I should set the X-over to? Heres the manufacturer limits for each speaker.

FRONTS

MD130 (tweet) 2k - 30k

MD140/2 (mid) 700 - 6k

MD170 (Woofer) 35 -3500

REAR FILL

MD160 (rear fill) 400 - 4k  ..... This will run close to full range at low power. I may cap the highs off, sugestions???

SUBS

ID V.3 (Infinite baffle) I havent found their range yet but I figure they are the same as most all subs? Whats a good freq to run at?

Also I read that there may be a FAQ floating around on how to properly set gains. Im using a clarion HU with 4v (I think becasue its the old DRX9255) with a line driver to the symmety. The symmetry has adjustable output up to 10v. I think I read something about using a scope to set this. Does anyone have any tips/tricks on how to do this? Im guessing that the X-over points need to overlap a little to create a smooth transition?

Am I forgetting anything technical that I need to configure to properly set up my stereo?

My plans are Woofers in the doors (.8'^3 sealed) Mid and tweet in kickpannels (self contained so airspace is not a requirement), 6.5" mids (.5f'^3 sealed) as rear fill. I got those requirements straight from dynaudio. Subs are Infinite baffle (4 x 12").

So I install the speakers, wire the car up, set my gains (Help please), set my X-over points (help needed here too), and then Im set, the rest is cosmetic whic hI can handle. Is there anyhting Im not taking into consideration? Im planing on installing a High output alt also, but I can handle that.

SORRY for bouncing all over the place. This forum has taught me there is a lot more to installing than hooking up the wires tweaking the gains until im happy and setting the EQ to what I like. This will be my first install where every move and purchase was 100% pre-calculated.

I don't know of a FAQ (but that's a good idea) on adjusting electronic crossovers, but here's my suggestions for your setup (if it doesn't sound right you can adjust from these points):

Sub: low pass @ 80 Hz.  Woofer: if your symmetry is the model with dual bandpass outputs, use bandpass 2 set to 80 Hz and 800 Hz; if yours does not have dual bandpass outputs, use the lowpass at 800Hz.  Mid: bandpass between 800 Hz and 3.5 Khz.  Tweeter: highpass at 3.5 Khz.  Set your slopes to 12 db/octave to make things easier.

There is no need to "overlap" crossover points as the slopes will create a natural overlap.  Indeed, if you do overlap them you will create unnesessary peaks at the cross point.

How are you amplifying this setup?  Matching amplifier gains will be a trick with this many channels of amplification.  I suggest you do not need a line driver between your HU and the symmetry.  Set the symmerty output voltage no higher than the max input sensitivity of your amps.  If you really want to get a setup like this "right," a tool like a real time analyzer would come in really handy!  And be careful with how much power you throw at your sub in an IB mounting - do not exceed the RMS rating for free-air (about 250 watts I believe for ID.)

If you use the audible distortion method for setting gain I described in the thread referenced above, make sure you use 0db ref test tones in the center of the crossover band for each of your amplifiers.

Thanks DYon. I spent several hours last night reading up on X-overpoints and Gain settings. I do have the Symmetry with dual bandpass outputs. It has 2 HP, 2 BP, 2 Allpass, 1 LP, and 28 band 1/3 oct EQ. The reason for the line driver is becasue its built into the symmetry. They call it a balanced line input, so its supposed to be there, Im not jsut amplifing my headunits output.

So I need to do further research on the sensitivity of my amps gain inputs and I need to make sure I do not set the output of the symmety higher than the amps can handle. I think I am going to invest a few bucks into paying someone to RTA my car after I get it all installed and make it sound good at its baseline (NO EQ set). I think Im going to also look into buying some test CDs fr sound Q. I like the idea of usign IASCA SQ cd to set stage and sound field. I really hope I dont have to add more tweaters. I read that using soft dome tweets i nthe kicks can cause a rainbow effect that can olny be fixed by adding attnuated tweets in my A-pillars. I think my dynaudios should be alright, i had them in kicks before and they sounded great.

I am amplifing this setup with 4 amps.

4x75 , 2x120, 2x120, 1800x1. 

2x120 to the tweets, 2x75 mids, 2x 120 midbass woofer, 2x 75 Rear fill, 1800x1 to the 4 12"

Im debating on weither I should swap the mids and tweets. Give the tweets 75w or give the mids 75w the tweets can handle more RMS per their spec sheet., and I figure I want them to come throguh strong since they are soft dome. All amps are monitor 1 except the big one is HiFonis Colosus. This is a true Tri-amp front set up. I will have total active control of each speakers X-over and gains.

Yes, swap the power for the mids and tweets.  Midrange frequencies require 20% more power than tweeter frequencies.  (Do some research on "equal loudness curves.")  Also, the RMS rating on tweeters is WITH their recomended crossover, which attenuates 60-70% of the available power.  Tweeters "rated" for 100 watts RMS can usually only handle 30 or so watts in thier frequency band.  I think 1800 watts is too much for 4 ID V.3 woofers in free air.  That will place 450 watts on each woofer and in an IB mounting you can easily overdrive them.  Unless I'm wrong those woofers can only handle 250 watts RMS.  If you angle the mids and tweets upwards towards the center of the listening area you will get best results.  I love the sound of fabric dome tweeters, but mounting them in kick panels in a car can be problematic.  You will probably end up boosting from around 4.5Khz to about 7Khz with your EQ to compensate for the dead band caused from placement so low.  Adding addditional tweeters is not usually necessary unless you plan to compete in SQ comps.

Sounds like a good setup.  Lots of toys to tweak with.  Symmetry systems (is your's in a rack?) are great.

Thanks again for the great info. As far as the power rating for the ID 12"'s, I got the recomendation straight from the techs at ID. So if they blow Im going ot yell at them for some new subs. You said I need to add tweets only if I plan on competing, unfortunitly even if I put all the money in the world into my car it won't win a SQ competiton simply becasue its a convertible with a lout exhaust. Its just not a SQ competion car, but its my toy! Every desision Ive made has been discused with the manufacturers of both the amp and speaker so I should be set. I will place a few final phone calls to Dynaudio, ID, and arc audio before I turn it all on to make sure they agree with all the decisions that have been made. You said that fabric domes in kickpannels are problematic? Is there a better place to mount the tweet and mid? Im up for anything. Lastly no, my symmetry isnt the rack mount model, its the EPX2 with 28band EQ. (I wish I could find the DSP chip to add-on to it. Ive been searching ebay for weeks)

Best of luck and be sure to let us know how it turns out!

Tweeters placed below ear level need to "project" in order to create a proper soundstage.  Fabric domes tend to sound more neutral and have a wider dispersion.  Metal domes tend to be more focussed and sharp but have longer throw.  (Horn tweeters tend to have the longest throw.)  So they can be "problematic" in that much of the sound details can get lost in the footwells.  That's all I meant, and it's also what's meant by the "rainbow" effect: cascade filtering of the sound spectrum due to low placement and interaction with the vehicle's materials and geometry.   Fabric domes tend to sound best when closest to ear level... so even though it is nearly impossible, the best placement for the mid and tweet is up on the dash...

So the only other option would be to mount BOTH the mid and tweet next to each other in the dash. Since, like you said thats nearly imposible, Ill stick to kickpannels and adjust my EQ to compensate. Thanks for the advice is invaluable, have a great holiday!

P.S. jsut send me a bill for you time :)