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Discussion Starter · #1 ·
I asked question a few weeks ago, and companies I was directed to either dont do this or will only build a passive that is not bi-amp able.

I have a set of MB Quart Q xovers that I want to use. I have a set of JBL 504Gti that I am want to biamp with quart xovers. I was looking at the points and the JBL likes a xover point around 4 to 4.5 K and the passive xover is crossing over around 2.5. Does anyone know a person or place that I can send my passives to have the xover point raised. I love the slopes (Selectable 18 or 24) and the Bi-amp ability but I just need to change the xover point up. I have to have a passive that I can bi-amp for this install.

I am using a eclipse 8445 with 3 outputs. One will go to sub, the bandpass output will go to a JL 300/2 driving a set of mid bass. The final output will go to a JL 300/4 using all 4 channels to drive the mids and tweets of the JBL 504set.
 

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For just a 12db/oct crossover you'd have to swap out a cap and a coil, for 18db or 24db the components involved may double or triple. There's no easy "one thing to change and it's now a different crossover point".
To do it properly you'll also want to change the midrange's lowpass point, so there's less gap between its current 2.5k lowpass and the tweeter's new 4k or 4.5k highpass.
I'd recommend either building networks your own from scratch, or finding some crossovers that will work for you in their stock configuration.

Better yet, use an electronic crossover and go active- you'll have more control, less amplifier output soaked up in passive components, and it might even be cheaper in the long run. You're using 4 channels to run 4 speakers, you're already halfway there.
 

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Discussion Starter · #3 ·
I want to use the xovers and time alignment in the head unit. Since the JBL 504 is a coax I dont have to worry about seperate time alignment for the mid and the tweeter. If I have to go the route of getting a passive network made, who can do this? Basically, I need it to be bi-amp capable and minimum of 18db slopes around 4 to 4.5k. I also have seen some passive xovers that people made that were bigger than some of my amps. I want to keep them a reasonable size.
 

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Why are you biamping them? Are they in the front or rear? My first instinct would be to tell you to biamp them and use the crossovers built into that deck to do an active crossover system.

Evan
 

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Discussion Starter · #5 ·
They are in the front, no rears. My deck wont do 4 way active, I have to use one passive for my system or find a way to go 4 way active. Passive is cheaper and easier. Basically output one is high pass sent to my 4 channel running the tweet and mid in my kickpanel. Output two is a bandpass to a 2 channel running midbass in doors. Output 3 is lowpass going to my sub. The only way to go 4 way active is do go with a processor which I dont want to do. I dont have to worry about time alignment in the front or highpass because the set is coax. So where can I get my passive fixed/changed or get one built?
 

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A company called XTC used to custom make passives in any configuration, with any crossover points, slopes, and speaker impedances. I don't know if they're still around, I think they're the same company that makes the foam speaker baffles since their logo looked the same.

I used to have some 3-way ones from them that were specifically made for certain speakers that I had at the time, that was a long time ago though. It looks like now they make individual networks for each driver.

A quick Google search pulled them up:
http://www.vertekxtc.com/
Click on "passive crossover filter networks", then click on high pass, low pass, or bandpass to see the options.
 

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Oh okay, I understand what you are doing. Just wanted to make sure you weren't overlooking an easy solution.

Best of luck finding/building an appropriate crossover.
 
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