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alt whine that I dont think was there before, with amps off even!

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  • alt whine that I dont think was there before, with amps off even!

    Its kind of annoying too, im 95% sure when I put the system in I had 0 alt whine, 2.5% sure it was very minor and 2.5% sure it was there. But it seems to me that its new because even with the amps off (remoted by m2atx) when I crank my car I can hear it whine as it cranks up. Seems to really only make noise below 3000rpm too. I checked all connections and they are all good, could it be some other source of interference?

    I have a line driver coming from DURWOOD which hopefully shows up soon, that has different selectors to possibly reduce ground loops noise, where do I start?

    (note) this seems to have happened after one of my 5.25" excursions blew on me, and it also seems more dominant on the driver side of the car (ie if I sit in the pass side its not as loud as it is in the driver sear)

    Maybe I missed a connection coming loose or something somewhere, but would that even cause alt whine? Its clearly rpm related

    edit: and before you even mention the stick: http://www.mp3car.com/vbulletin/showthread.php?t=79248 im there still reading through it, Id like some suggestions tho

    edit2: also, my motherboard doesnt have any grounds connected to it (from the screw holes) are they a common 12V ground? Could I add a string of wire to the mobo to the chassis of my car with my m2atx?

  • #2
    It whines when the amplifiers are not on at all? That might be something with your car. Maybe a bad bearing in your altenator or the belt is slipping. You shouldn't have any alternator whine through you speakers if the amp is off. Otherwise check to make sure none of you speaker wires are touching ground. That is all I can recommend.
    System always under construction


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    • #3
      still no luck, and the gf had to take the car all day. Wont be able to figure it out till tomorrow >_<

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      • #4
        When you get it back, try running it without the RCAs plugged into the amp. If it still does it then its associated with the amp or speakers. Also if the Soundcard is PCI and if its tweaked a little it can cause engine whine.
        System always under construction


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        • #5
          rca's unplugged still noise, amps off, still noise.... WHAT THE HELL. I havent disconnected + yet

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          • #6
            damn I am clueless. Maybe you need an engine tuneup. Spark plugs, new wires. I am just throwing that out there. Unless you check each speaker wire with a multimeter to ground and see if one wire is touching ground in your car I really don't know.

            Here is another troubleshooting guide.

            https://myeporia.eporia.com/resource...ote%201002.pdf
            System always under construction


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            • #7
              Engine is ok, but why would that cause noise from the speakers? I have a tweeter mounted up by the windshield and I put my ear to it, it is distinctly coming from speaker. Even if it were a slipping belt, that wouldnt do speaker noise...


              bad amp?

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              • #8
                Let understand this, you get alternator whine with the amplifiers receiving no remote turn on?

                IF this is the case it is either speaker wire grounding (chaffed cable) or inductance.

                Disconnect your speakers wires from the speakers (at the drivers).

                Still got noise?

                This is a *&^$$ of a problem. Basically your drivers are picking up RF through the driver coil. Options?
                1\Move the drivers (possible but not feasible)
                2\Shield the driver. The name of this metal that is used in computer cases to shield drivers is MuMetal. Don't bother trying to buy thi$$$$$$$$$. Salvage a reduntant section from an old computer. This is the best option, other choice is to aluminium foil and ground it around the driver coils.
                3\Try exchanging drivers, last resort, some are less susceptible than others.

                No noise

                Great
                Are you using passive crossovers?
                If so these can pick up noise through their coils.

                Reconnect the speaker wires, and disconnect the speaker wires from the amplifier side of the passive crossovers.
                Noise?

                This ones easier to deal with.
                1\ move the (offending) passive crossover. 1 or 2" is usually enough, simply extend the wires for movement and rinse and repeat.

                No noise

                If the noise is coming from all speakers it is most likely the amplifiers.
                Are your amplifier cases grounded?
                This can help amplifier case to shield RF.

                Last one is unusual and possibly only feasible with the amplifier running.
                Empty RCA input is acting as an antenna.
                Mute all empty RCA inputs as "good standard practise"
                Hopefully you know how to make mute plugs.

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                • #9
                  ill look into this more, ill check to see if the amp is leaking power through the speakers, if I pull the + off, then the noise stops it has to be some sort of power issue, if its still there, ill disconnect the speaker wires at amp, and check, if not then uhh... I guess resolder the connections on the speaker, I can only hear it from the tweeters, mostly the left, I only have 1 component set hooked up. Passive crossovers as in an mbquart crossover yes, (pretty sure thats passive, no power going to it, just speakers wires in and out, crossed over internally)

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                  • #10
                    hah, know what it was? My 4awg wire going from battery in trunk to hood area was too close to my in-active crossover. This set is disconnected, and I also know why it wasnt there before too, its because when I disconneted the blown 5.25" woofer I must have moved the wires a little bit and the power wire was too close to the crossover. Thats it, move 4awg to go around it and problem solved, thanks guys

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                    • #11
                      Already finished typing this, before I saw you post...
                      Great news.

                      anyway this might be useful to others..

                      Inductance doesn't require a direct power source.

                      For example a transformer. These are magnetically coupled and not directly coupled.

                      For inductance to work it requires
                      1\something resembling alternating current (no DC transformers)
                      2\close proximity to the magnetic field (magnet field strength is inversely proportional to distance, rated as BL)
                      3\ Enough length of conductor to induct in the offending magnetic field. The greater the amount of wire in close proximity to the magnetic field the stronger the signal, and therefore why coils etc are likely candidates over a single run of wire.

                      Radio frequency (RF) requires
                      1\An antenna,that is, a conducting object, for example you holding onto a TV antenna.
                      2\Amplifier circuit. Basically Radio frequency is travelling right through you but you don't perceive it because you lack a suitable amplifying circuit.
                      3\ radio frequency emittance.

                      Your alternator (alternating current) can and does produce all of the above. In fact so do your electric motors, ECU's, switching power supplies ("D" class amps) and to some extent even A/B amps because of there pulse mode power supplies.

                      To receive this noise you need the above conditions, remove one of the legs of the triangle and it cannot give you noise.
                      Same as fire triangle..
                      1\ heat
                      2\ oxygen
                      3\ combustibles.

                      same a forum arguements..
                      1\ Controversial subject
                      2\ Closed minded
                      3\ Passion

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                      • #12
                        Good stuff. I have never run into this problem so I was drawing a blank.
                        System always under construction


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                        • #13
                          yeah thanks again for your help, I couldnt understand why with no rca and no speaker wire it was STILL making the sound, never though to check for power wires near crossovers. Ah well live and learn, sounds better

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                          • #14
                            Radiated noise my friends

                            Coils of wire near BIG AC ripple ='s noise. Alternators produce what kind of voltlage? AC of course (that's why their called alternators! Duh!!)

                            But there are diodes inside (BIG ones) and they rectify the AC to make DC. But if you have a dual trace scope and connect to the DC wire anywhere in the car you'll see a sort of stright line (DC) and then HUGE spikes of AC ripple. AC on the DC. Causes all types of problems. Can radiate for 10 to 20 feet sometimes. Think old corvettes here!

                            Good call, good fix! way to go.

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                            • #15
                              Originally posted by CarAudioGuru View Post
                              Coils of wire near BIG AC ripple ='s noise. Alternators produce what kind of voltlage? AC of course (that's why their called alternators! Duh!!)

                              But there are diodes inside (BIG ones) and they rectify the AC to make DC. But if you have a dual trace scope and connect to the DC wire anywhere in the car you'll see a sort of stright line (DC) and then HUGE spikes of AC ripple. AC on the DC. Causes all types of problems. Can radiate for 10 to 20 feet sometimes. Think old corvettes here!

                              Good call, good fix! way to go.
                              10 to 20feet? you mean itll travel that long (rippling) along the wire or it will make a "field" 10 to 20 feet away? The latter seems kind of ridiculous though.

                              What about inline DC capaciters? Would that reduce the ripple of AC? I do know what you are talking about but wouldnt it make sence for that DC signal to actually BE a DC signal and not alternation inbetween?

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