Sound System: crossover or bass blockers

[Mors]

Hey everyone, I’m currently stock piling all of my accessories and am starting now with my audio setup. I haven’t done anything with car audio in about 25 years so I'm hoping the guru’s of this forum can help me with a few novice questions.

2023 Maverick XLT - NON B&O
—-Ordered Sept 2022
—-Build week provided is 3/30. Crossing my fingers I will get it in a few months!

Audio Setup
6.5”’s JL Audio C2-650 Component speakers
4” JL Audio C2-400x rear speakers
Kicker 47Key200.4 DSP amp
PlugnPlayKits.com wiring harness

Dealing with the front 6.5” and tweeter speakers. Are both of these scenario’s ok to do and/or which one is better and why?

1. Replace each speaker with the original wiring. I would only use the 72-5602 and 72-5600 harnesses to connect them to the original wiring. (I wouldn’t the JL crossover). Instead of the JL crossover, I would use something like the crutchfield bass blockers for the tweeters.
   1. Also, are the bass blockers needed in this scenario using the 200.4 amp?
   2. Is a blocker needed for the 6.5”s?
2. Replace 6.5”s and tweeters with both hooked up to the JL crossover.

Question 3: where can or does the kicker 47Key200.4 get its power from? The pictures look like it gets it from the dash wiring while using the plugnplay harness kit. I’m not seeing the power wire coming out of the harness.

Thanks for any advice!

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[Darnon]

If you're having the Kicker Key running all the speakers instead of just Bi-Amping the front you will want to have some sort of frequency protection for the tweeters. The stock ones have high-pass (bass blocker) caps integrated onto the back of them while the JLs likely assume they're being attached to the crossover. So ideally you should use the crossover as it will also provide a low-pass filter so the woofers aren't trying to play above their range. I'm not sure how accessible the point is where the non-B&O front wiring splits.

Theoretically could break out the low-/high- parts of the crossover to attach closer to their component elements if one wanted to be fancy.

If you aren't going to have a separate subwoofer then you probably don't want bass blockers for the 6.5"s, and the Key has a built in high-pass option if you really need to cut out some low bass.

 

[colinl]

If you're having the Kicker Key running all the speakers instead of just Bi-Amping the front you will want to have some sort of frequency protection for the tweeters. The stock ones have high-pass (bass blocker) caps integrated onto the back of them while the JLs likely assume they're being attached to the crossover. So ideally you should use the crossover as it will also provide a low-pass filter so the woofers aren't trying to play above their range. I'm not sure how accessible the point is where the non-B&O front wiring splits.

Theoretically could break out the low-/high- parts of the crossover to attach closer to their component elements if one wanted to be fancy.

If you aren't going to have a separate subwoofer then you probably don't want bass blockers for the 6.5"s, and the Key has a built in high-pass option if you really need to cut out some low bass.

agree with the upper part.

the part I bolded really depends on what kind of music a person listens to, and especially, how loud.

an amplified 6.5 midrange without a high pass filter will definitely overextend and be trashed in short order if you were to play hip-hop very loud. like, anything more than low volume. I've done it. repeatedly, I'm ashamed to say.

the 60hz filter on a kicker key is a good match because it has a steep 24db/octave crossover. if you use a bass blocker with only 6db/oct then you have to filter higher or you'll probably blow up the midrange at moderate to high volume when something with very low bass is played.

The Key set to 60hz with a 24db/oct slope means that 30hz is -24db, that's easy enough. but to have that same protection with a 6db/oct slope it has to be set at 240hz. (60x2, 120x2.) you will lose a LOT of midbass performance with a 6db/oct filter at 240hz. I've intentionally done it with 4" speakers or shallow-mount 5.25. I have 150hz and 300hz bass blockers that are only 6db/oct. I briefly had a 150hz bass blocker on a 6.5 and it sucked compared to using 80hz on the Key, and then selecting 60hz was even better.

the other reason to use an amp instead of a bass blocker is efficiency. the amp is still pushing the voltage and it's getting filtered by a bass blocker, that's a lot less efficient than a dsp or amp filtering it before it gets amplified.

 

[colinl]

Just noticed one of your questions remained unanswered.

It appears that the custom harness pictured has the Key's integrated 20A fuse. I circled it. I can't see the ground but it's in there too, I'm sure.

I haven't used that harness but I have to say I personally would prefer not to power it like that. Just because it doesn't blow the ACIM fuse doesn't mean it's a good idea. Besides the load on the ACIM wiring, I also don't like connecting the ground back into the harness. The total length of the ground is still reasonably short, but any kind of shared ground can be a source of noise or ground fault.

If you're going to add a powered sub or another amp with a sub enclosure, I would take the time to install a proper power wire to the battery, use a distribution block, and then ground each amp to bare metal (use sandpaper or steel wool to remove paint from the chassis) as short of a run as you can manage.

The power wire and fuse for the Key 200.4 are puny, so I understand why someone would do this, but that doesn't mean it's a best practice.

 

[Juanderosa]

I'll answer this question. Go with #2.

Bass blockers usually are to keep the bass out of the midrange/midbass speakers. They are not designed to keep the bass out of the tweeters. That's what the JL Audio crossover that it came with is designed to do. Plus, it's a much steeper slope (so it keeps out more of the frequencies more quickly to protect the tweeter from blowing up). And you can go quickly from sound coming out of the tweeter to tweeter blowing up making no sound. The fix to that is a new tweeter(s). Plus time to pull them, ship them, etc.

Here is a picture of some random JL Audio crossover, so you can see that it's got more components.

Plus having the midrange in the door play some of the tweeter frequencies isn't ideal either (it won't hurt it, but you don't want the same frequencies coming from the door and dash at the same time). So the crossover JL provides is optimized for the mids to do mids stuff and the tweeters to do tweeters stuff. And to keep it from coming back as "defective".

Dealing with the front 6.5” and tweeter speakers. Are both of these scenario’s ok to do and/or which one is better and why?

1. Replace each speaker with the original wiring. I would only use the 72-5602 and 72-5600 harnesses to connect them to the original wiring. (I wouldn’t the JL crossover). Instead of the JL crossover, I would use something like the crutchfield bass blockers for the tweeters.
   1. Also, are the bass blockers needed in this scenario using the 200.4 amp?
   2. Is a blocker needed for the 6.5”s?
2. Replace 6.5”s and tweeters with both hooked up to the JL crossover.

Thanks for any advice!

 

[Mors]

Thank you all!

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