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Discussion Starter · #1 ·
Hello everyone,
I’m getting a bit frustrated with my front tweeters crackling on bass notes at higher volumes. Hopefully someone can help me figure this out! Here we go..
I have a 2016 Jeep Wrangler with the stock 430 HU. I installed alpine SPS-610c 6.5 components in the rear and MTX Terminator65 components in the front. Both have inline crossovers. The speakers are being powered by a Pioneer GM-D1004 4 channel amp that powers 50 Watts RMS per channel. I used a LOC(PAC AOEM-CHR3) to tap into the factory speaker wiring to connect to the amp via RCAs. I have the output speaker wiring from the amp going back into the factoring wiring behind the HU. The amp does not have a gain knob, but the LOC does for each channel. I have to gain set low, and when I turn up the volume, I hear what sounds like distortion or crackling on just the front tweeters. The rear sounds fine, and at medium to low volumes the entire system sounds great. I’ve since replaced the MTX tweeters with Alpine SPS-110TW tweeters but it didn’t improve anything. I’ve checked all wiring and it looks fine. If I turn the gain down really low it goes away, but then my system lacks any bass. Any ideas how to get rid of this crackling? I also activated the high pass filter and it didn’t do anything. Help!!
 

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Only two reasons

1) distortion. Could be over driving them, clipping

2) xover is too low.

How much power do you have for the tweeters?
You mentioned that turning the gain down removed bass. Are all the speakers on one amplifier?

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Sometimes the bass amp speaker outputs can "crosstalk" with the high amp inputs. If your bass amp outputs are near your high amp input cables, this might be the issue.
 

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Discussion Starter · #4 ·
Only two reasons

1) distortion. Could be over driving them, clipping

2) xover is too low.

How much power do you have for the tweeters?
You mentioned that turning the gain down removed bass. Are all the speakers on one amplifier?

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Ok, Thanks. Each channel is getting 50 RMS. So I guess the tweeter is getting 22.5 and the woofer is also getting 22.5? And yes- all speakers are connected to the same 4 channel amp.
 

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Ok, Thanks. Each channel is getting 50 RMS. So I guess the tweeter is getting 22.5 and the woofer is also getting 22.5? And yes- all speakers are connected to the same 4 channel amp.
That's not How it works. Each speaker gets 50 watts if you have a passive xover on it.
What freq is the tweeter set to?

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Discussion Starter · #6 ·
That's not How it works. Each speaker gets 50 watts if you have a passive xover on it.
What freq is the tweeter set to?

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Ok. The tweeters have the built in crossover. I can’t adjust it. According to Alline the in-line crossover “provides a 12 dB/Octave slope”
 

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OP: You said "each set of speakers has an inline crossover", that would be called a passive crossover. I'm not picking on you, just clarifying for others.
You also said you ran your amplifier output back into the factory wiring, you should NEVER EVER TRUST THE FACTORY WIRING. Run your own speaker wire, it's not that hard or expensive. They do downright stupid crap in the factory wiring harness.
I doubt anyone could positively determine what your problem is without dedicated speaker wire, but here's my two guesses:
1) There's something downright stupid in your factory speaker wiring.
2) You're clipping the amp, turn it down.
I lean toward #1. 50 watts rms should get pretty loud before any craziness blasts its way through a passive crossover to the tweeter.

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Discussion Starter · #9 ·
OP: You said "each set of speakers has an inline crossover", that would be called a passive crossover. I'm not picking on you, just clarifying for others.
You also said you ran your amplifier output back into the factory wiring, you should NEVER EVER TRUST THE FACTORY WIRING. Run your own speaker wire, it's not that hard or expensive. They do downright stupid crap in the factory wiring harness.
I doubt anyone could positively determine what your problem is without dedicated speaker wire, but here's my two guesses:
1) There's something downright stupid in your factory speaker wiring.
2) You're clipping the amp, turn it down.
I lean toward #1. 50 watts rms should get pretty loud before any craziness blasts its way through a passive crossover to the tweeter.

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Thanks for clarifying the crossover verbiage- I’m still learning. I’m going to wire one set of components directly from the amp tomorrow. We will see if that does the trick. Thanks for the suggestion!
 

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OP: You said "each set of speakers has an inline crossover", that would be called a passive crossover. I'm not picking on you, just clarifying for others.
You also said you ran your amplifier output back into the factory wiring, you should NEVER EVER TRUST THE FACTORY WIRING. Run your own speaker wire, it's not that hard or expensive. They do downright stupid crap in the factory wiring harness.
I doubt anyone could positively determine what your problem is without dedicated speaker wire, but here's my two guesses:
1) There's something downright stupid in your factory speaker wiring.
2) You're clipping the amp, turn it down.
I lean toward #1. 50 watts rms should get pretty loud before any craziness blasts its way through a passive crossover to the tweeter.

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As long as the factory speaker wires are 18g (they are in my Grand Cherokee and I tapped into them for the JL Fix82 I had and now just tapped in for rearfill without issue) he should be fine. I realize they do some crazy stuff with wiring bundles from the factory but it's highly unlikely it's the op's problem. He can run 50rms of music (NOT FULL DUTY) all day every day through them even in a tight bundle without issue. My guess is the inline passive crossovers aren't providing enough protection at higher volume OR the amp is clipping.
 

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As long as the factory speaker wires are 18g (they are in my Grand Cherokee and I tapped into them without issue) he should be fine. I realize they do some crazy stuff with wiring bundles from the factory but it's highly unlikely it's the op's problem. He can run 50rms of music (NOT FULL DUTY) all day every day through them even in a tight bundle without issue. My guess is the inline passive crossovers aren't providing enough protection at higher volume OR the amp is clipping.
The craziness in factory wiring that I speak of is not the closeness of wires in the bundle, it's the things that they think are okay to run through the same conductor, different colors on each end of the same wire, etc.
The bundling and size of the conductor is certainly not an issue, but I guarantee there is something really stupid going on in there. My question is "Is that the problem, or is it something else?".
I have traced enough factory wires to determine that cars should not work correctly with the wiring in them, but they do.

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I agree, and can personally attest to tapping into factory wiring being totally fine, but in a case like the OP's where he's troubleshooting a possibly difficult issue, I'd want to run all my own quality 16 gauge OFC to each driver in the system.

This way, all possible speaker wire issues are taken out of the equation as a possible cause of the problem. So it's a diagnostic step as well as a quality upgrade. And as has been stated, it isn't as difficult as you think, it just takes time to pop some panels off, maybe remove the seats (usually just 4 bolts and a few connectors), then fish some wire under the carpet/sill plates/etc.

If after new wire is ran, the issue persists, my guess would be that whatever is the root cause will be easier to identify and repair/replace as finding a wiring issue, especially one that's potentially part of a factory harness/connector bundle can be very challenging, even for an experienced technician.

But I must confess, I'm OCD about wiring and often go too far ensuring everything is quality material, routed correctly, wrap wiring in loom, heat shrink, etc., so my advice is colored by my own compulsiveness.

Just my .02.
 

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Ok, Thanks. Each channel is getting 50 RMS. So I guess the tweeter is getting 22.5 and the woofer is also getting 22.5? And yes- all speakers are connected to the same 4 channel amp.
The input to the passive sees 0-50W depending on the volume.
The woofer gets the lion's share, and the tweeter typically on,y needs ~15% for typical music.

In reality the amp is supplying a voltage, and the woofer freqs gobble up the majority.
Then the tweeter signal ride on top of the woofer's low frequency and that is when clipping happens.
 

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It's clipping or an inadequate/malfunctioning crossover network on the tweeters.

You said this happens on just the MTX set correct? You replaced the MTX tweeters with the Alpine tweeters and the same thing happened? Did it happen right away when you swapped the tweets or did it take some time for them to start distorting? I can't find much info on the MTX set, but from what I can gather they have a simple passive inline with the tweeter and nothing on the mid. If that's the case it might not provide an appropriate slope/frequency to adequately protect them at higher volumes or on particularly dynamic peaks. It might be that there was a batch of bad capacitors (which provide a high pass filter) that have failed due to heat or something.

If the crossovers are to blame it's entirely possible that both sets of tweeters are now blown, especially if you noticed things were fine at first and progressively got worse with only a little bit of volume making them distort.

So you still have the complete set of Alpines in the back or did you use the tweeters from the Alpines in the front? You didn't say if you bought a new set or just swapped them over. You might try swapping the passive filters and tweeters from the Alpines to the front and see if the problem resolves. If so you know it's bad passive crossovers on the MTX. If you don't have any tweeters left that you know for sure are still good you'll need to buy some new ones. It might require a bit of swapping things around the narrow down what is good and what is bad.

There's one more thing I can think of, and that's the front mids. When mids blow, you can get bad crackling sound as you describe from them, and you wouldn't be the first person to mistake that sound as coming from the tweeters instead. I know this probably isnt' the case, but it's something to double check.
 

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The input to the passive sees 0-50W depending on the volume.
The woofer gets the lion's share, and the tweeter typically on,y needs ~15% for typical music.

In reality the amp is supplying a voltage, and the woofer freqs gobble up the majority.
Then the tweeter signal ride on top of the woofer's low frequency and that is when clipping happens.
Unless they have the tweeter padded down. That is not how it works. They both get the same voltage, same wattage

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Discussion Starter · #16 ·
It's clipping or an inadequate/malfunctioning crossover network on the tweeters.

You said this happens on just the MTX set correct? You replaced the MTX tweeters with the Alpine tweeters and the same thing happened? Did it happen right away when you swapped the tweets or did it take some time for them to start distorting? I can't find much info on the MTX set, but from what I can gather they have a simple passive inline with the tweeter and nothing on the mid. If that's the case it might not provide an appropriate slope/frequency to adequately protect them at higher volumes or on particularly dynamic peaks. It might be that there was a batch of bad capacitors (which provide a high pass filter) that have failed due to heat or something.

If the crossovers are to blame it's entirely possible that both sets of tweeters are now blown, especially if you noticed things were fine at first and progressively got worse with only a little bit of volume making them distort.

So you still have the complete set of Alpines in the back or did you use the tweeters from the Alpines in the front? You didn't say if you bought a new set or just swapped them over. You might try swapping the passive filters and tweeters from the Alpines to the front and see if the problem resolves. If so you know it's bad passive crossovers on the MTX. If you don't have any tweeters left that you know for sure are still good you'll need to buy some new ones. It might require a bit of swapping things around the narrow down what is good and what is bad.

There's one more thing I can think of, and that's the front mids. When mids blow, you can get bad crackling sound as you describe from them, and you wouldn't be the first person to mistake that sound as coming from the tweeters instead. I know this probably isnt' the case, but it's something to double check.
The distortion was present from the start. I bought new alpine tweeters(did not move them from the back) to replace the MTX tweeters and right from the start I heard the same distortion/crackling on bass notes. It definitely the tweeters. When I disconnect them the noise goes away. I’m going to wire directly from the amp today and see if that solves anything. Thanks for your help
 

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I have traced enough factory wires to determine that cars should not work correctly with the wiring in them, but they do.

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I think it's more likely that you didn't do the best job in tracing the wires. You'll never convince me that the millions of cars on the road shouldn't work because the wiring is wrong, haha.

Factory wiring is almost always perfectly fine, and is in a lot of ways better than running your own wiring. The factory will do a better job running the wiring safely without getting damaged, whereas the average DIY installer won't have easy access to where the wire should be ran.

Also, there isn't really anything that a wire could be doing to cause distortion. OP, I can say with almost certainty that your OEM wires aren't the problem.
 

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Discussion Starter · #18 ·
One more thing- when I activate the amps high pass filter, it doesn’t completely solve the problem, but it gets noticeably better. Another thing I noticed is when I turn the volume knob up and down at loud volumes, it seems to cause the same clipping sound in the tweeter.
 

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One more thing- when I activate the amps high pass filter, it doesn’t completely solve the problem, but it gets noticeably better. Another thing I noticed is when I turn the volume knob up and down at loud volumes, it seems to cause the same clipping sound in the tweeter.
What freq does the HPF effect? Unless it is 5khz (which would cut the misbass off entirely) it wouldn't have any effect

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The amp does not have a gain knob
What? That's odd so I googled it. This is one of those small power bricks that are intend to hide under the dash. I am not sure exactly what Pioneer was trying to accomplish by leaving off the gain control.

Anyway, I have a ton of questions and a few suggestions.

1) Why are you using a line output converter? Apparently that amp can accept speaker-level inputs.

2) Is this your only amp in the system? Someone above commented that you may have cross-talk between the inputs/outputs of this amp and a bass amp.

3) Where is the amp mounted?

My hypothesis is that you have the gain on the line output converter to high and/or the passive crossovers have failed. You can verify that it is not the wiring by uninstalling the speakers (and the crossovers) and then hooking them up directly to the amp. If the problem goes away then the problem is between the speaker and the amp. I would also consider disconnecting the line output converter and using speaker-level inputs to see if that resolves the issue.
 
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