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Discussion Starter #1
Hey everybody. I just wanted to seeksome of your expert advice. So I’m having an issue in my system in my grand Cherokee currently. I’m running a 4 channel and a mono amp though a dsp feeing active components up front and I have different sub setups in auditioning all the time.

So here is what I’m currently having an issue with. I have a sub set up that I can run at four ohms, I set up that I can run at three ohms (w7) and a setup I can run at 4 ohms. The issue only ever happens when I run the subwoofer amp at two ohm. It’s a kicker 40kx1200. Only on certain songs it happens even when it’s 2 ohms. Most are fine. When bass hits hard and bass knob on dsp ( audio control dm608) is cranked up the front speakers sort of make a snap crackle sound. When I turn the knob down no issue. They’re not blown as I crank it down asap. And they sound beautiful still. They’re morel tempo ultra comps off a
Jl rd400 75x4 amp soon to be an Arc ks300.4. So the quick answer is don’t run it at 2 ohm in sub. But I wanna get best benefit from it. I thought is it a voltage thing? And then I said no... headlights don’t dim nor does dash etc. Jeep has 180 amp alt. Gotta be something else. Then today I realized that I think I still have four gauge wire run for power and ground to a distribution block that’s all hidden away in my rear quarter panel and feeds the amplifiers which are also hidden away. I initially had the four gauge run when I was only upgrading with a small subwoofer at the time and never upgraded the power wire as I started building things out. My install buddy never brought it up.

Sorry for that novel but that brings me back to why I’m here ttoday... Jeep has a voltmeter built in to display. Just recently realized this! Ive only ever looked at it with music blaring while I drive. Alway 13.7 was the minimum it dropped to. Usually at 14.4 or 14.3. BUUUUUUUT I was parked today and looked at it it was dropping at full volume to 12.9 Maybe touched a little lower.

With a 1200w sub Anp and 300-400 4ch I need to run zero gauge right? Or can I just run a second 4 gauge to each amp? Or do I need to do this and a big 3? Just a big 3? Still no headlight dim in park even now, but I’m. It sure what best steps to do to eradicate the issue and enjoy all the songs I like not just most of them.

I understand audio hear well just not the electrical part of it. I greatly value all the advice I get here! Thanks in advance.
 

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After a quick read, the wiring isn’t the problem, it sounds like you’re clipping the snot out of the signal. You said you have the bass knob cranked. That’s a good hint that you’re clipping the signal and getting gobs of distortion. While being parked your alternator isn’t doing much (or nothing if the engine is off), that’s why the voltage dropped lower. It was still higher than the battery voltage, so that’s not a problem.
 

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Discussion Starter #3
Ok so the dsp bass connected to the sub output and controlling the sub amp level can cause the front speakers to clip? Hmmm, even though they’re connected to an amp that the remote doesn’t effect? Excuse my ignorance. I didn’t think that was possible.
 

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Discussion Starter #4
After a quick read, the wiring isn’t the problem, it sounds like you’re clipping the snot out of the signal. You said you have the bass knob cranked. That’s a good hint that you’re clipping the signal and getting gobs of distortion. While being parked your alternator isn’t doing much (or nothing if the engine is off), that’s why the voltage dropped lower. It was still higher than the battery voltage, so that’s not a problem.
Meant to reply to your message and not add to thread. Sorry.

Ok so the dsp bass connected to the sub output and controlling the sub amp level can cause the front speakers to clip? Hmmm, even though they’re connected to an amp that the remote doesn’t effect? Excuse my ignorance. I didn’t think that was possible
 

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The noise is what has me curious. No, clipping the sub amp won’t affect the front speakers, but voltage drop shouldn’t cause the fronts to crackle. Turn off the sub completely and play music at a level that typically causes the issue, does the problem remain?
 

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Discussion Starter #6
The noise is what has me curious. No, clipping the sub amp won’t affect the front speakers, but voltage drop shouldn’t cause the fronts to crackle. Turn off the sub completely and play music at a level that typically causes the issue, does the problem remain?
This is exactly why I’m perplexed. When I turn the bass knob down when it’s doing it while leaving main volume up, the speakers immediately stop doing it. Makes no sense. Another thought I had is.... I have my factory head unit and we had to fool it into recognizing the load coming from the factory amplifier to the DSP, and my guy installed some resistors in the lines. I was wondering if maybe the resistors might not be the right impedance And could it be that? I ordered some load sending adapters audiocontrol makes for the Jeep to see if that helps as well. Waiting on delivery.
 

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it could be wiring issue. You need to be looking at the voltage at the amps not at the front of your car. If the single 4 awg wire is too small to handle the current, it's causing a voltage drop at the load. The source only drops in voltage by how much current is being demanded of it. It isn't dropping very low because your electrical is able to handle the load put on it, but your single 4awg wire can't handle the current and so anything after it see's a greater voltage drop. An amp receiving a low voltage could exhibit issues.
 

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Discussion Starter #8
This is exactly why I’m perplexed. When I turn the bass knob down when it’s doing it while leaving main volume up, the speakers immediately stop doing it. Makes no sense. Another thought I had is.... I have my factory head unit and we had to fool it into recognizing the load coming from the factory amplifier to the DSP, and my guy installed some resistors in the lines. I was wondering if maybe the resistors might not be the right impedance And could it be that? I ordered some load sending adapters audiocontrol makes for the Jeep to see if that helps as well. Waiting on delivery.
That makes sense! I will upgrade the power wire since we will be putting the arc amp in anyway on Monday. Fingers crossed it helps make a difference.
 

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Discussion Starter #9
I should have also added that it has done it with my previous front speakers as well before I put the Morel in and with my previous amplifiers that were only temporarily installed. So it’s not the amplifiers or the speakers I would come to the conclusion. My installer is convinced it’s not the gains.
 

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I had a similar problem years ago where the midrange amp would cut out during heavy bass. I connected my voltmeter to the + and - terminals of the amp that powered the front speakers. The voltage was strong until I really cranked up the system. Then the voltage would sag, and as soon as it dropped below 11V, the amp would shut off. Then I took voltage measurements at the battery, and the voltage barely dropped when the bass hit. I checked the amp ground and it was good, so I upgraded the power wire and that solved the problem.
 

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Discussion Starter #12
I had a similar problem years ago where the midrange amp would cut out during heavy bass. I connected my voltmeter to the + and - terminals of the amp that powered the front speakers. The voltage was strong until I really cranked up the system. Then the voltage would sag, and as soon as it dropped below 11V, the amp would shut off. Then I took voltage measurements at the battery, and the voltage barely dropped when the bass hit. I checked the amp ground and it was good, so I upgraded the power wire and that solved the problem.
That’s exactly what I thought may be the issue. I can’t thank you all enough. I’ll report back in a week on this.
 

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Measure the voltage at the amp, like others have mentioned. If your power wire is restricting power to an amp, then your fuse should be blowing, as long as it's fused safely.
 

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Measure the voltage at the amp, like others have mentioned. If your power wire is restricting power to an amp, then your fuse should be blowing, as long as it's fused safely.
Not necessarily. We fuse for catastrophic failure (a short) which pulls 100s of amps instantly and can cause a wire to burn / melt and start a fire. He's pushing the limits of his wire and the resistance is rising, hence why he's getting a voltage drop at the amps, but he isn't pulling so many amps as to blow a correctly rated fuse for the wiring.
 

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Not necessarily. We fuse for catastrophic failure (a short) which pulls 100s of amps instantly and can cause a wire to burn / melt and start a fire. He's pushing the limits of his wire and the resistance is rising, hence why he's getting a voltage drop at the amps, but he isn't pulling so many amps as to blow a correctly rated fuse for the wiring.
A properly fused wire should never heat up to the point that it's causing that kind of voltage drop.
 

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Keep in mind just because you go over the rated amperage does not mean the fuse wire melts. I don't know what the formula is, but a fuse could cook for some time on a slightly over amperage situation.
 

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Keep in mind just because you go over the rated amperage does not mean the fuse wire melts. I don't know what the formula is, but a fuse could cook for some time on a slightly over amperage situation.
Sure, and they don't blow instantly, but any situation where the wire is causing enough resistance to result in a voltage drop that big is a bad situation and a fuse should be put in place with a rating that would cause it to blow before reaching this extreme.
 

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Discussion Starter #18
Sure, and they don't blow instantly, but any situation where the wire is causing enough resistance to result in a voltage drop that big is a bad situation and a fuse should be put in place with a rating that would cause it to blow before reaching this extreme.
I’m pretty sure it’s 100 amp fuse in power line. It’s ofc copper 4gauge. Just ordered a second ofc 4 gauge kit to run as well that has 150a fuse.
 

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The noise is what has me curious. No, clipping the sub amp won’t affect the front speakers, but voltage drop shouldn’t cause the fronts to crackle. Turn off the sub completely and play music at a level that typically causes the issue, does the problem remain?
Does this sound like exactly the same problem that DavidRam gave up on?


I should have also added that it has done it with my previous front speakers as well before I put the Morel in and with my previous amplifiers that were only temporarily installed. So it’s not the amplifiers or the speakers I would come to the conclusion. My installer is convinced it’s not the gains.
I would almost bet the gains on the amps are OK, but the DSP gain is too high... mostly because you say in a different place that turning bass down causes the noise to abate.

You have a bunch of finger crossing solutions. You could get lucky, but I think you will probably need an O-scope or some other way to really work out what is happening.

Just changing power wire etc, without measuring or understanding if they are the problem seems like a potential waste of time and money.


If you leave the bass cranked up and disconnect the fuse for the bass amp, then does it still make the noise on the tweeters?
 
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