Popping sound from amp
Dec 30, 2005, 06:15 PM
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Popping sound from amp
I need help. I just installed the Alpine 9855 deck into my Evo8 SSL using the correct wire harnesses from soundgate and metra. I'm 99.9% sure I've wired everything correctly. However, when I first turn on the accessories to turn the HU on, I hear this pretty loud pop from the speakers.
It simply sounds like the amp just got turned on, as it should be, and some "static" is being released to the speakers in a loud pop.
After that, everything sounds good; fade back to front, balance left to right, so I'm pretty sure the soundgate harness is fine.
I hooked up the blue wire from the soundgate harness with the accessories lead from the car, which is also connected the accesory lead from the metra harness. So it's basically 3 wires coming together. Everything is capped/crimpped. Although, the remaining wires that I didn't need (ie speaker wires) are bundled up with zip ties and wrapped with clear duct tape (didnt have any electrical tape).
I doubt anything from those wires would cause it, since the signal going to the speakers is coming exclusively from the amp.
Now, I don't have pics or details on the wiring...so I was hoping I'd find someone who has a similar "problem", if in fact, this is a problem. The stock infinity HU didn't exibit this behavior..but also, note that the 9855 is putting out 4v from the preamps.
Thanks!
~Jayson
It simply sounds like the amp just got turned on, as it should be, and some "static" is being released to the speakers in a loud pop.
After that, everything sounds good; fade back to front, balance left to right, so I'm pretty sure the soundgate harness is fine.
I hooked up the blue wire from the soundgate harness with the accessories lead from the car, which is also connected the accesory lead from the metra harness. So it's basically 3 wires coming together. Everything is capped/crimpped. Although, the remaining wires that I didn't need (ie speaker wires) are bundled up with zip ties and wrapped with clear duct tape (didnt have any electrical tape).
I doubt anything from those wires would cause it, since the signal going to the speakers is coming exclusively from the amp.
Now, I don't have pics or details on the wiring...so I was hoping I'd find someone who has a similar "problem", if in fact, this is a problem. The stock infinity HU didn't exibit this behavior..but also, note that the 9855 is putting out 4v from the preamps.
Thanks!
~Jayson
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Dec 31, 2005, 09:21 AM
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i upgraded because i wanted a deck that can play mp3's, and eventually when i get an ipod, one that is ready to interface with it. im not good at judging how "good" something sounds...but the sound from my new alpine is noticeably (and incredibly) better.
anywhoo, i went and checked the wiring again and now it's leading me to believe it may be the deck itself. please bear with me as i try to explain why i think so...and please tell me if im smoking crack or not.
- first off, i don't even need to ground it with the supplied ground lead. i was mucking around with it and didn't have it grounded and it still turned on and played. it's actually grounded through the antenna (it looks like the antenna connector splits into two wires, presumambly one is the ground)...which also makes sense because the stock infinity HU didn't have any ground wires. regardless, i tried several grounding "scenarios":
a) i did several spots to ground from, using the ground lead (with and without the antenna connected)
b) i tried not using the ground lead at all, and just double checked the antenna..yielded the same results
- i looked at all the wires, unravelled them and made sure there were no shorts
- i also know, the "pop", doesn't come from the amp turning on because if i turn the deck off, before turning the accessory off, then turn it back on, it doesn't pop until i actually hit source to turn the deck back on
- also, if the HU isn't actively sending a signal through the preamps (ie, face is off, or turned off), and I turn the engine on, the "noise" from the engine can be heard through speakers, like interference...even when the rpm idle speed changes, the sound changes with it. then i turn the HU on, then it pops, then the sound is completely clean. i can mute it and there's no interference noise at all.
- i also tried disconnecting the rca preamps, and there's no pop at all. if i disconnect just one set (ie front preamps, or the rear preamps), i hear some interference.
i mean, doesn't it sound like (no pun intended) that the deck is just sending some noise (and pops) when it's not actively sending a signal to the amp..so when i first turn the accessory on, and the deck is still in it's "off" state thats when the pop comes out, and then after half a second or whatever, it finally returns to the state it was at (ie playing an mp3).
anywhoo, i went and checked the wiring again and now it's leading me to believe it may be the deck itself. please bear with me as i try to explain why i think so...and please tell me if im smoking crack or not.
- first off, i don't even need to ground it with the supplied ground lead. i was mucking around with it and didn't have it grounded and it still turned on and played. it's actually grounded through the antenna (it looks like the antenna connector splits into two wires, presumambly one is the ground)...which also makes sense because the stock infinity HU didn't have any ground wires. regardless, i tried several grounding "scenarios":
a) i did several spots to ground from, using the ground lead (with and without the antenna connected)
b) i tried not using the ground lead at all, and just double checked the antenna..yielded the same results
- i looked at all the wires, unravelled them and made sure there were no shorts
- i also know, the "pop", doesn't come from the amp turning on because if i turn the deck off, before turning the accessory off, then turn it back on, it doesn't pop until i actually hit source to turn the deck back on
- also, if the HU isn't actively sending a signal through the preamps (ie, face is off, or turned off), and I turn the engine on, the "noise" from the engine can be heard through speakers, like interference...even when the rpm idle speed changes, the sound changes with it. then i turn the HU on, then it pops, then the sound is completely clean. i can mute it and there's no interference noise at all.
- i also tried disconnecting the rca preamps, and there's no pop at all. if i disconnect just one set (ie front preamps, or the rear preamps), i hear some interference.
i mean, doesn't it sound like (no pun intended) that the deck is just sending some noise (and pops) when it's not actively sending a signal to the amp..so when i first turn the accessory on, and the deck is still in it's "off" state thats when the pop comes out, and then after half a second or whatever, it finally returns to the state it was at (ie playing an mp3).
Dec 31, 2005, 09:38 AM
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Try upgrading the ground on your alternator. Also, do you have the gain on the amp turned all the way up? Since the sound changes with engine rpm I'd say it's "alternator whine". That's usually a grounding issue.
Dec 31, 2005, 09:41 AM
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Try a different set of RCA cables before you go to the head unit. A quality set. A cheap cable could cause your popping noise, not likely but doesnt hurt to try. What type of head unit are you running, and is your head unit grounded to the chasis of the car or using the antenna only as well???
The Ten Commandments
I. The best cure is prevention. I can't overemphasize this point. If you've ever spent an entire weekend tearing an installation apart in order to eliminate some noise, you know what I mean. Take the time to sketch the system out before you begin the install. This graphic representation of the installation will help you to avoid introducing ground loops and will serve as a road map for eliminating noise if it is present.
II. Don't introduce ground loops. Ground loops are created whenever an audio ground is established at more than one location. Theoretically, the only place the audio ground should be connected to the chassis ground is at the source unit. In my experience, I've found that in systems that have noise problems, a ground loop is the culprit nine times out of ten.
III. Never run signal wires alongside power cables. This is especially true in installations where high powered amplifiers are used. Large amplifiers are capable of drawing large currents. These currents vary with the musical demand of the program material as does the electromagnetic field surrounding the power cable. The more current that flows through the wire, the bigger this field becomes. If audio cables are located in close proximity to this fluctuating electromagnetic field, noise could be induced into the system.
IV. Always use 100% shielded audio cable. This will insure maximum protection against induced noises by power cables and other sources of electromagnetic interference. Good audio cables are not cheap. If you prefer to make your own cables, I would recommend using a wire with a foil shield surrounded by a drain wire.
V. Never use the ground wire in the vehicle's OEM radio harness. This wire usually makes a very poor ground due to it's length, small wire gauge, close proximity to other power wires, and unknown termination point. Instead, ground the source unit directly to the chassis or firewall.
VI. Make sure the amplifiers have a good audio ground reference. In order for the amps to function properly, the audio ground must be referenced to chassis ground at the source unit. If it is not, the amplifier could oscillate. To check for a good ground reference, take a volt-ohm meter (VOM) and measure the resistance between the chassis of the radio and the shield of the RCA line level outputs of the radio. This reading should indicate a direct short. If this is not the case, grounding the shield of the RCA line level outputs to the chassis of the radio will probably be necessary.
VII. Keep amplifier power ground wires as short as possible. The longer a wire, the more resistance it has. When a current flows through a resistance, a voltage drop is produced. Because of this, the ground reference at the amplifier's circuit board is no longer the same as that at the chassis of the vehicle. This ground potential differential can lead to noise and improper operation of the amp.
VIII. Don't connect all of your amplifier ground wires under one bolt. Contrary to belief, this is not required if the rest of the system is installed properly. If you do connect more than one power ground wire under a single bolt, you run the risk of amplifier ground modulation. This is caused by the current demands of, for example a woofer amp, modulating the power ground wire of a tweeter amp. This results in a squeaking noise that can be heard over the tweeters whenever bass notes hit.
IX. Make sure all levels are set correctly. Level setting is a critical part of the installation process. If done properly, maximum system signal to noise ratio can be obtained. Keep in mind that you want to drive the audio cables that feed the amps in the rear of the car as hard as possible. To do this, reduce the gain of the amplifiers to minimum. Turn up the volume on the source unit to 80% of maximum. Now adjust the input sensitivity of the amplifiers upward until the maximum intended loudness is obtained.
X. Noise filters can only reduce noise, not eliminate it. A noise filter is just that, a filter. And like any other filter (crossover network, etc.), it works by modification, not elimination. Some installers rely on filters heavily. In some instances a filter may prove necessary, but I believe that if the system is installed properly, a filter is usually not required.
Turn On/Off Thump
Turn on thump can vary from a slight pop to a mind shattering, teeth rattling BOOM! This thump is caused by the audio circuitry stabilizing when power is applied. Most amplifiers and source units have muting circuitry that lasts a couple of seconds to allow these fluctuations to subside before passing a signal. However, if the amplifier un-mutes before the source unit or any other accessory, you better watch out. Here are some things to try if you have turn on thump.
Verify that the amp has a good audio ground reference. (See rule 6 of the Ten Commandments of noise free installation.)
Don't install the system so the amplifiers can be switched on when the source unit is turned off.
If you still have thump, add a turn on delay module in line with the remote turn on wire to the amp.
The Ten Commandments
I. The best cure is prevention. I can't overemphasize this point. If you've ever spent an entire weekend tearing an installation apart in order to eliminate some noise, you know what I mean. Take the time to sketch the system out before you begin the install. This graphic representation of the installation will help you to avoid introducing ground loops and will serve as a road map for eliminating noise if it is present.
II. Don't introduce ground loops. Ground loops are created whenever an audio ground is established at more than one location. Theoretically, the only place the audio ground should be connected to the chassis ground is at the source unit. In my experience, I've found that in systems that have noise problems, a ground loop is the culprit nine times out of ten.
III. Never run signal wires alongside power cables. This is especially true in installations where high powered amplifiers are used. Large amplifiers are capable of drawing large currents. These currents vary with the musical demand of the program material as does the electromagnetic field surrounding the power cable. The more current that flows through the wire, the bigger this field becomes. If audio cables are located in close proximity to this fluctuating electromagnetic field, noise could be induced into the system.
IV. Always use 100% shielded audio cable. This will insure maximum protection against induced noises by power cables and other sources of electromagnetic interference. Good audio cables are not cheap. If you prefer to make your own cables, I would recommend using a wire with a foil shield surrounded by a drain wire.
V. Never use the ground wire in the vehicle's OEM radio harness. This wire usually makes a very poor ground due to it's length, small wire gauge, close proximity to other power wires, and unknown termination point. Instead, ground the source unit directly to the chassis or firewall.
VI. Make sure the amplifiers have a good audio ground reference. In order for the amps to function properly, the audio ground must be referenced to chassis ground at the source unit. If it is not, the amplifier could oscillate. To check for a good ground reference, take a volt-ohm meter (VOM) and measure the resistance between the chassis of the radio and the shield of the RCA line level outputs of the radio. This reading should indicate a direct short. If this is not the case, grounding the shield of the RCA line level outputs to the chassis of the radio will probably be necessary.
VII. Keep amplifier power ground wires as short as possible. The longer a wire, the more resistance it has. When a current flows through a resistance, a voltage drop is produced. Because of this, the ground reference at the amplifier's circuit board is no longer the same as that at the chassis of the vehicle. This ground potential differential can lead to noise and improper operation of the amp.
VIII. Don't connect all of your amplifier ground wires under one bolt. Contrary to belief, this is not required if the rest of the system is installed properly. If you do connect more than one power ground wire under a single bolt, you run the risk of amplifier ground modulation. This is caused by the current demands of, for example a woofer amp, modulating the power ground wire of a tweeter amp. This results in a squeaking noise that can be heard over the tweeters whenever bass notes hit.
IX. Make sure all levels are set correctly. Level setting is a critical part of the installation process. If done properly, maximum system signal to noise ratio can be obtained. Keep in mind that you want to drive the audio cables that feed the amps in the rear of the car as hard as possible. To do this, reduce the gain of the amplifiers to minimum. Turn up the volume on the source unit to 80% of maximum. Now adjust the input sensitivity of the amplifiers upward until the maximum intended loudness is obtained.
X. Noise filters can only reduce noise, not eliminate it. A noise filter is just that, a filter. And like any other filter (crossover network, etc.), it works by modification, not elimination. Some installers rely on filters heavily. In some instances a filter may prove necessary, but I believe that if the system is installed properly, a filter is usually not required.
Turn On/Off Thump
Turn on thump can vary from a slight pop to a mind shattering, teeth rattling BOOM! This thump is caused by the audio circuitry stabilizing when power is applied. Most amplifiers and source units have muting circuitry that lasts a couple of seconds to allow these fluctuations to subside before passing a signal. However, if the amplifier un-mutes before the source unit or any other accessory, you better watch out. Here are some things to try if you have turn on thump.
Verify that the amp has a good audio ground reference. (See rule 6 of the Ten Commandments of noise free installation.)
Don't install the system so the amplifiers can be switched on when the source unit is turned off.
If you still have thump, add a turn on delay module in line with the remote turn on wire to the amp.
Last edited by BADEVO; Dec 31, 2005 at 09:50 AM.
Dec 31, 2005, 10:02 AM
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Dec 31, 2005, 10:15 AM
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thanks for the replies guys...glad i can come here and get some good feedback.
im not sure how much gain is set on the amp...ill have to check on that...if there's even a way to set it on this particular amp (it's an infinity amp, came stock with SSL package, which is under the seat).
so yes, i think you're right...about it being alternator whine. didn't really know that term existed, but i think that's what best describes the sound...but let me reiterate, that the alternator whine is only audible when the deck is off...otherwise, when it's playing music, there's no whine at all. can you explain what you mean by upgrading the ground on the alternator?
the rca cables that im using are the ones made by soundgate. they were $25, so i don't think those are cheap (http://www.soundgate.com/index.php?r...&usereferrer=1. i picked this cable because i wanted to keep the stock wiring that runs from the (stock) infinity amp under the seat to the dash and not have to cut the wires.
my HU is the Alpine CDA-9855 (bought new from bargainunlimited.com). On round one (initial install), it was grounded through the antenna and the ground lead, on one of the screws that holds the deck in place. On round two (today), I tried grounding the ground lead on different parts of the car, but still the same results. I finally just removed the ground lead, insulated it with tape, and just have it grounded through the antenna. I hear no difference from the different ground scenarios I've tried.
I would have to agree that the "pop" that i hear is probably best described as a "thump", as you pointed out. I would have to say it's a medium thump...where if someone got in my car, they wouldn't be rattled by it, however, would prompt them to saying "wtf was that?" so you're saying a thump is something that's to be expected and most amps account for it by doing some "startup" muting? So what does that mean for me, exactly? i never heard any thumps from my stock HU.
so bottom line for me right now, is that no matter how i ground it, it still thumps. the alternator whine is only audible when the unit is turned off but not when it's playing music.
ThunderOZRacer, can you please not jack my thread. k thx.
im not sure how much gain is set on the amp...ill have to check on that...if there's even a way to set it on this particular amp (it's an infinity amp, came stock with SSL package, which is under the seat).
so yes, i think you're right...about it being alternator whine. didn't really know that term existed, but i think that's what best describes the sound...but let me reiterate, that the alternator whine is only audible when the deck is off...otherwise, when it's playing music, there's no whine at all. can you explain what you mean by upgrading the ground on the alternator?
the rca cables that im using are the ones made by soundgate. they were $25, so i don't think those are cheap (http://www.soundgate.com/index.php?r...&usereferrer=1. i picked this cable because i wanted to keep the stock wiring that runs from the (stock) infinity amp under the seat to the dash and not have to cut the wires.
my HU is the Alpine CDA-9855 (bought new from bargainunlimited.com). On round one (initial install), it was grounded through the antenna and the ground lead, on one of the screws that holds the deck in place. On round two (today), I tried grounding the ground lead on different parts of the car, but still the same results. I finally just removed the ground lead, insulated it with tape, and just have it grounded through the antenna. I hear no difference from the different ground scenarios I've tried.
I would have to agree that the "pop" that i hear is probably best described as a "thump", as you pointed out. I would have to say it's a medium thump...where if someone got in my car, they wouldn't be rattled by it, however, would prompt them to saying "wtf was that?" so you're saying a thump is something that's to be expected and most amps account for it by doing some "startup" muting? So what does that mean for me, exactly? i never heard any thumps from my stock HU.
so bottom line for me right now, is that no matter how i ground it, it still thumps. the alternator whine is only audible when the unit is turned off but not when it's playing music.
ThunderOZRacer, can you please not jack my thread. k thx.
Dec 31, 2005, 04:00 PM
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I didn't realize you were using the stock amp. Now it makes perfect sence. That happens alot with aftermarket heads and factory amps. Does that hu have high (speaker) level outputs? Not many aftermarket ones do. Now I'm thinkin' you probably need a better high to low level adaptor.
You said you can only hear the whine when the radio is off. How about if it's on but turned all the wat down? Not with the mute button pushed but the volume all the way down.
For up grading the ground on the alternator I meant just upgrading to a larger cable. That usually helps some.
You said you can only hear the whine when the radio is off. How about if it's on but turned all the wat down? Not with the mute button pushed but the volume all the way down.
For up grading the ground on the alternator I meant just upgrading to a larger cable. That usually helps some.
Dec 31, 2005, 05:06 PM
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yeah, the preamps are pushing 4v.
the whine is only ever audible when the deck is off. muted or zero'ed volume doesn't whine at all...not even a little hint of it.
im coming to believe that i have two different issues at hand.
1) the thump is just your "normal" thump because of the amp turning on before the preamps are energized. best bet for me is probably just buy or make a turn-on delay for it.
2) then there's the whine. i think the whine is probably from the fact that the cables on the soundgate adapter aren't well shielded. i mean, im looking at them, and they're pretty damn skinny. i might explore rewiring from the amp to the hu with better cables, as you've suggested.
but the thing im surprised about is that there's gotta be someone out there, with the SSL package, upgraded their HU (preferrably similar to mine with the high voltage preouts), using the same harnesses, etc...i would just like to hear if they've experienced the same problem(s) or if mine are isolated...grr...
i think that's where i stand.
happy new year's everyone!
"Stay in school."
- Mr. T
EDIT:
oh yeah, come to think of it, the accessory wire is running right along with the signal wires, since they're all bundled into this "neat" (sarcasm) cable with round connectors. so if the accessory signal is dirty, and coupled with the fact that the wires for the signals aren't well shielded, then that noise will most likely contaminate the signal, will it not? and then since maybe the preamp is so high, voltage wise, the signal is less likely to get contaminated when there is a signal. does that make sense?
the whine is only ever audible when the deck is off. muted or zero'ed volume doesn't whine at all...not even a little hint of it.
im coming to believe that i have two different issues at hand.
1) the thump is just your "normal" thump because of the amp turning on before the preamps are energized. best bet for me is probably just buy or make a turn-on delay for it.
2) then there's the whine. i think the whine is probably from the fact that the cables on the soundgate adapter aren't well shielded. i mean, im looking at them, and they're pretty damn skinny. i might explore rewiring from the amp to the hu with better cables, as you've suggested.
but the thing im surprised about is that there's gotta be someone out there, with the SSL package, upgraded their HU (preferrably similar to mine with the high voltage preouts), using the same harnesses, etc...i would just like to hear if they've experienced the same problem(s) or if mine are isolated...grr...
i think that's where i stand.
happy new year's everyone!
"Stay in school."
- Mr. T
EDIT:
oh yeah, come to think of it, the accessory wire is running right along with the signal wires, since they're all bundled into this "neat" (sarcasm) cable with round connectors. so if the accessory signal is dirty, and coupled with the fact that the wires for the signals aren't well shielded, then that noise will most likely contaminate the signal, will it not? and then since maybe the preamp is so high, voltage wise, the signal is less likely to get contaminated when there is a signal. does that make sense?
Last edited by JGo; Dec 31, 2005 at 05:13 PM.
