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I have a set of 3 way speakers that I intend to run semi active. the mid/tweeter are located close to each other so due to amp channel limitations I am going to run those passive and run the woofer (along with the sub of course) active.

Can I just use the 3 way passive crossover and not use the woofer output? not sure how impedance is managed. I am using a good amp so 2ohms is not an issue, the set is 4ohms.
 

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You could hook them up on a test bench and just measure the resistance at the crossover terminals without the midbass woofer connected. Provided the impedance is within tolerance of your amp you should be fine. There should be no adverse affects by omitting a driver.
 

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I have a set of 3 way speakers that I intend to run semi active. the mid/tweeter are located close to each other so due to amp channel limitations I am going to run those passive and run the woofer (along with the sub of course) active.

Can I just use the 3 way passive crossover and not use the woofer output? not sure how impedance is managed. I am using a good amp so 2ohms is not an issue, the set is 4ohms.
This will NOT present the amp with a 2ohm load -- the load will be closer to the 4ohms that the crossover set is rated for. That's how passive crossovers work -- as the signal reaches the top of the midrange's freq range, impedance increases. Meanwhile, as the signal freq continues to go higher, the impedance of the tweeter gradually decreases. So by trading off the increasing impedance of the mid vs. the decreasing impedance of the tweeter, the overall impedance seen by the amp will remain right in the 4ohm range.

And yes, it will be ok to run the passive crossovers w/o the woofer.
 

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This reminds me of a question that I been meaning to ask. I’m not sure if I worded the question the right way but I believe there’s enough there for somebody to understand my thought.

I drive a hatchback so the rear speakers factory locations are more or less almost right next to the shoulders of the front seats. I have a four channel amplifier and instead of doing 1 channel to each factory location, I was thinking of not using the the rear factory locations. Instead, I was thinking of doing 1 mid and 1 tweeter to each front door and using kick panels for the other 2 mids. I find the tweeters in this components set are very bright hence why I don’t wanna use all four. I have 2 sets of JBL GTO609C, (so 4 mids, 4 tweeters, 4 passive crossovers.) So as far as wiring I was thinking to do from channel 1 off amplifier to the drivers location to a passive crossover. From the passive crossover to the one tweeter and wire the 2 the two woofers as 1. How would that effect the speakers?
 

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I have a set of 3 way speakers that I intend to run semi active. the mid/tweeter are located close to each other so due to amp channel limitations I am going to run those passive and run the woofer (along with the sub of course) active.

Can I just use the 3 way passive crossover and not use the woofer output? not sure how impedance is managed. I am using a good amp so 2ohms is not an issue, the set is 4ohms.
Maybe drop a 4-ohm resistor across the woofer?

You would likely be wise to put a HPF ipbetween the Hu and the amp so that the woofer frequencies are removed. Harrison labs make an RCA unit.

The majority of the power is used for the woofer, and majority of the voltage excursion too, so removing that woofer range from the input will likely give more headroom.
 

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unless the crossover is meant for semi active I wouldnt do it,
tried this with a certain brands 3 way and was actually guided by there tech dept that yes all would be ok only to find that my amp hated the end result impedance and go into protection mode.

speak with a tech from the manufacturer and ask them is my best advice
 

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with passive x-over you need to connect all speakers to the X-o unit.... if it is
3-way crossover you should connect MB/M/TW
 

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I drive a hatchback so the rear speakers factory locations are more or less almost right next to the shoulders of the front seats. I have a four channel amplifier and instead of doing 1 channel to each factory location, I was thinking of not using the the rear factory locations. Instead, I was thinking of doing 1 mid and 1 tweeter to each front door and using kick panels for the other 2 mids. I find the tweeters in this components set are very bright hence why I don’t wanna use all four. I have 2 sets of JBL GTO609C, (so 4 mids, 4 tweeters, 4 passive crossovers.) So as far as wiring I was thinking to do from channel 1 off amplifier to the drivers location to a passive crossover. From the passive crossover to the one tweeter and wire the 2 the two woofers as 1. How would that effect the speakers?
Not using the rear speaker locations is a very good idea. Proper rear fill is very complicated even when using typical speaker location on the rear package shelf, and it will be even worse when the rear speakers are that close to the listener.

Running 2 woofers in each kick panel could provide some more upfront bass, but it will also make it more difficult to install and tune. 1st of all, DO NOT run both woofers off the same passive crossover! That will change the impedance that the woofer output of the crossover sees, and that in turn will change the crossover frequency. It could even fry the crossover, becuz it's expecting a 4ohm load and u would be running it at 2ohm.

The other approach would be to use the other set of passive crossovers to run just the woofer. But apparently, based on other replies to this post, using only 1 output from a passive crossover is bad. That doesn't make sense to me based on my understanding of how passive crossovers work, so I'm hoping some1 will enlighten me.
 

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with passive x-over you need to connect all speakers to the X-o unit.... if it is
3-way crossover you should connect MB/M/TW
He could connect the MB output to a resistor.
If the input was HPF'ed, then a lot of the MB power would be gone.
 
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