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Discussion Starter · #1 ·
I'm going to install some components with crossovers in my 2015 ST3. I tried reading through the speaker only testimonial thread, and the 2014+ upgrade warning thread. I've also checked the wiring diagrams for the sony amp. I can't find a solid answer, can someone point out a few things for me? I only have a LC2i and amp for a sub, looking to replace speakers connecting to the factory amp only. I've also disconnected the front center speaker.

1.The front door speakers have independent wires for the mids and the tweeters. it's safe to disconnect the factory tweeters and leave the those wires alone, using the mid's wires to give power to the new speaker's crossovers which will give then split to the new woofer and tweeter.
2. the rear door speakers have one set of wires which I use with the new speakers (crossover to new tweeters and woofers)

Am I right here?
 

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What you will likely find is that the tweeters are already crossed over with only high frequencies going to them (since they have their own line provided from the amplifier) and the woofers will have a bandpass crossover (crossing the high frequencies and very low frequencies out). If you are going to install new components with the factory amplifier supplying the audio, you will need to forego the crossovers that came with the speakers and use the tweeter wires to supply the tweets and the woofer wires to supply the woofers with audio.
 

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I'm going to install some components with crossovers in my 2015 ST3. I tried reading through the speaker only testimonial thread, and the 2014+ upgrade warning thread. I've also checked the wiring diagrams for the sony amp. I can't find a solid answer, can someone point out a few things for me? I only have a LC2i and amp for a sub, looking to replace speakers connecting to the factory amp only. I've also disconnected the front center speaker.

1.The front door speakers have independent wires for the mids and the tweeters. it's safe to disconnect the factory tweeters and leave the those wires alone, using the mid's wires to give power to the new speaker's crossovers which will give then split to the new woofer and tweeter.
2. the rear door speakers have one set of wires which I use with the new speakers (crossover to new tweeters and woofers)

Am I right here?
1.The front door speakers have independent wires for the mids and the tweeters. it's safe to disconnect the factory tweeters and leave the those wires alone, using the mid's wires to give power to the new speaker's crossovers which will give then split to the new woofer and tweeter. That is exactly what I did. I used the door woofers as inputs to the crossover since they are full range and left the stock tweeters unplugged.

2. the rear door speakers have one set of wires which I use with the new speakers (crossover to new tweeters and woofers) Same on this, I used the door woofer wiring as crossover inputs

One thing to keep in mind is that if you leave both tweeters up front unplugged and unplug the center channel, you may want to add resistors to those outputs on the amp. Nothing might happen, but with three speakers disconnected it is better to be safe than sorry.
 

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Discussion Starter · #4 ·
ok cool, so I can do either pretty much, but I should make sure there's still load on the tweeter channel. Chances are I'm going to use the woofer signal and use the components crossovers. I might just get some 4ohm resistors on amazon and go that route. Is the front woofer signal full frequency? I know both front and rear woofers have some cheap looking filter built in, so hopefully that's the case.
 

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ok cool, so I can do either pretty much, but I should make sure there's still load on the tweeter channel. Chances are I'm going to use the woofer signal and use the components crossovers. I might just get some 4ohm resistors on amazon and go that route. Is the front woofer signal full frequency? I know both front and rear woofers have some cheap looking filter built in, so hopefully that's the case.
All of these questions are answered above. BTW, I went with 10ohm/10watt resistors.

http://www.focusst.org/forum/focus-st-electronics/94305-my-anticipated-st3-audio-upgrade-3.html
 

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1.The front door speakers have independent wires for the mids and the tweeters. it's safe to disconnect the factory tweeters and leave the those wires alone, using the mid's wires to give power to the new speaker's crossovers which will give then split to the new woofer and tweeter. That is exactly what I did. I used the door woofers as inputs to the crossover since they are full range and left the stock tweeters unplugged.

2. the rear door speakers have one set of wires which I use with the new speakers (crossover to new tweeters and woofers) Same on this, I used the door woofer wiring as crossover inputs

One thing to keep in mind is that if you leave both tweeters up front unplugged and unplug the center channel, you may want to add resistors to those outputs on the amp. Nothing might happen, but with three speakers disconnected it is better to be safe than sorry.
It is good to know that the woofer output is full range. I found an RTA photo of the woofer output after I saw your reply: Untitled.png
 

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All of these questions are answered above. BTW, I went with 10ohm/10watt resistors.
honestly, I'd do this anytime I would add load resistors instead of using 4 ohm resistors, not only will it cause the amp to have to work less hard and run a little bit cooler, higher ohm resistors will have less current flowing through them and therefor wont create as much heat, and the cooler you run things, the longer they tend to last.

when I have to add resistors to OEM outputs on factory radios that have signal sensing outputs and shut down the outputs when a speaker is not detected like Chrysler's radio, I always try to use something like 16 ohm resistors, then I dont have to worry about the resistors overheating and having to add a heatsink to them as well.
 

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