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Location:
brisbane
Registered:
September 2005
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 stereo clipping+screech as turned off+background noises+HELP PLZ
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Thu, 10 November 2005 10:56
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hey guys
i got dilemmas with my stereo
ok ill tell all i can, basically i got 2 12" subs feeding off one amp, and 2 6" and 2 6"*9" running off the other.
pioneer p5750 headdeck
now my issue is that i recently got the car back from the auto electricians and put it back together (i had stripped tryna find why aircon wasnt workin properly, anyways, got it back and they had made probs worse so took it back again, and they have fixed those probs, they sed it was earthing and dodgy 20 odd yr old contacts and such things.
the stereo wasnt used when the issues were apparant(speeling?) and after gettin it all back together put a new cd i had burnt on and had it about half volume (pretty loud) with no engine running and midway thru this song it just starts clipping continually can hear nothin else just tickticktick, so im like ahhhh launch my self at head deck and turn down then off, switch it back on, seems to be gone, but if i listen closely theres the same clipping quieter in the background, and a high pitched hum.
when u turn it off, (i do this by button not by key coz acc has hardwired itself since i piggybacked it for alarm) it goes quiet and u hear the fan on one of the amps still runnin and as it shuts down u get this massive rip/screech/zipper doing up very loudly/something that dont sound healthy happening.
i havnt turned it up very far yet, but it seems as if it distorting a little bit aswell
can anyone suggest any reasons for this?
sorry bout the long post but im crappin me self, this stereo is my pride and joy and shes not a happy gal 
thanx guys
~andrew~
[Updated on: Fri, 11 November 2005 07:24]
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Location:
eastern suburbs, melbourne
Registered:
March 2005
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Re: stereo clipping and screech as turned off
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Thu, 10 November 2005 22:12
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try another cd. i have found that somtimes burnt cds make some wierd noises. try an original cd.
as for "u get this massive rip/screech/zipper doing up very loudly/something that dont sound healthy happening" if its just for a fraction of a second then dont worry about it.
mine does the same thing. its just switching of.
if it goes for a second or more thne you prob have a problem.
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Location:
Brisbane
Registered:
July 2005
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Re: stereo clipping and screech as turned off
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Thu, 10 November 2005 23:06
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...ok number one most likely cause is low voltage.
Especially since you say your accessories is hardwired. This jus means that it is possible something could be draining your battery all the time and making it shittier than it already is. How shitty is it???
Best way to test if this is the cause;
Turn unit off & drive round with some revs for a while. Shouldn be a prob for most of us...
Turn engine off. Test battery with multi meter for voltage. Should be round 13V
Turn stereo on with engine off. Crank it a little. If am right, music wont have those noises initially but you will watch the voltage drop in front of your eyes on the multimeter, and by the time you hit about 12.5V with a decent current draw (vol) you will start to get clipping and all sorts of scary noises.
Never run a powerful stereo with engine off and a stocko electrical system to support it.
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Location:
brisbane
Registered:
September 2005
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Re: stereo clipping and screech as turned off
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Thu, 10 November 2005 23:53
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yeah i tried the radio and it made it no better
low voltage, that may well be my problem, its a big battery thats been abused, i used to have to charge it every morning to start until i charged it for about 2 days straight, now shes seems alright but does suffer a bit
i think the alarm system constantly drains it, and anyone know if the led clock on the dash in the 82 corolla is meant to stay on? i didnt think it was but i may be wrong.
anywho back on topic, i still get that weird ass noise as i turn it off even with the car on, but it was at idle and im thnkin the battery may be fairly low as she hasnt been run for a week or so except to the auto electricians and back.
thanx mate, i may put the charger on it this arvo and see if she still does it
thanx
~andrew~
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Location:
Brisbane
Registered:
July 2005
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Re: stereo clipping and screech as turned off
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Fri, 11 November 2005 00:04
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Do you have a multimeter?
If you do take a few voltage readings; eng on/off stereo on/off revs high/low, and combinations thereof. Then post em here.
If you dont, knick the battery out of a late model car you will undoubtedly have access to somewhere handy. Like your neighbours garage. Test it with that.
Late model cars have generally better gear coz the elecs in cars hasnt got any less or simpler as the years tick by...
If you are even slightly suspicious that your battery spends it spare time sitting round with your car and chatting about the good ol early eighties, its way too fuckin old. 
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Location:
eastern suburbs, melbourne
Registered:
March 2005
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Re: stereo clipping and screech as turned off
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Fri, 11 November 2005 00:08
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the led clock on the ae82 dose not stay on.
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Location:
Brisbane
Registered:
July 2005
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Re: stereo clipping and screech as turned off
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Fri, 11 November 2005 00:15
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| Quote: |
the led clock on the ae82 dose not stay on.
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Unless your accesories has permanent power...
This will be a big prob when combined with a killa stez that will probably be the downfall of many a battery or alternator until you get it fixed.
There is no reason why installing an alarm should mean you put permanent power to your accesories circuit.
Did your auto elecky do this? If so get a new one. After you get a refund/rework on the present job.
If you did it, tell me what you did so we can fix... I think you will still need a new battery but at least you will get a good life out of a new one if all else is in good nic.
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Location:
brisbane
Registered:
September 2005
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Re: stereo clipping and screech as turned off
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Fri, 11 November 2005 00:30
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yeah got a multimetre, ill head out there bout 3.30 after my exams, ill let u know wat i get.
the battery isnt that old off memory its 2.5 yrs, i picked it up from the wreckers for $20 when my car only had dreams of being a rust heap paddy basher.
yeah the led has been stayin on ever since i put my alarm system in...ever since i piggy backed the acc line i had taken for my radio. so i duno wat caused it, one day im thinkin ill take it all apart and run 2 seperate acc's but i duno if that will help.
wat can u suggest?
thanx
~andrew~
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Location:
wollongong NSW
Registered:
August 2003
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Re: stereo clipping and screech as turned off
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Fri, 11 November 2005 03:14
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| love ke70 wrote on Fri, 11 November 2005 11:30 |
the battery isnt that old off memory its 2.5 yrs, i picked it up from the wreckers for $20 when my car only had dreams of being a rust heap paddy basher.
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youve had it for 2.5 years? well time for a new one IMO
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Location:
eastern suburbs, melbourne
Registered:
March 2005
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Re: stereo clipping and screech as turned off
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Fri, 11 November 2005 04:15
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if your electrics are good and you dont draw alot of curent with engine off, a battery should last a while longer then that.
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Location:
brisbane
Registered:
September 2005
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Location:
brisbane
Registered:
September 2005
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Re: stereo clipping and screech as turned off
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Fri, 11 November 2005 07:22
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ok well im now thinking its something rong with the headdeck as battery seemed fine didnt (nod)
umm the more engine noise when running i got no idea with unless the electricians rooted my electronic noise filter thingy :S
anywho, i got gain set right, bit low if anythin, and checked all connections and earths on the amps and nothing better
now the thing im finding atm is that if u have volume on zero u get this clicking in the background, thru all 6 speakers, so im guessing that its pickin up on somethin or somethin is buggered
wat can yas tell me?
im thinking head deck
as the noises come thru all 6 speakers which are from 2 seperate amps so im thinkin its not gonna be a single amp. hmm i got no idea
plz help
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Location:
brisbane
Registered:
September 2005
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Re: stereo clipping and screech as turned off
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Sat, 12 November 2005 00:34
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come on guys this thing is killin me, i need some help please
i know u sound gurus are out there, i know one of u even installs car audio, i just cant find u, but i will hehe
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Location:
Kita-Ku, Sapporo, Japan
Registered:
January 2003
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Re: stereo clipping and screech as turned off
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Sat, 12 November 2005 02:00
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| love ke70 wrote on Fri, 11 November 2005 16:18 |
Stereo on / Stereo off
engine off just keeps falling below 12/ 12.2
idle stereo 13.2 / 13.4
~3000 rpm 13.2 / 13.4
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KE70 has bosch alternator with 14.3V regulator.
your alternator is fuked and your "wrecker" battery is likely fucked also.
fix your alternator and spend a hundred bucks on a decent heavy duty battery and stop fucking around 
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Location:
Kita-Ku, Sapporo, Japan
Registered:
January 2003
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Re: stereo clipping and screech as turned off
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Sat, 12 November 2005 02:01
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| love ke70 wrote on Fri, 11 November 2005 18:22 |
now the thing im finding atm is that if u have volume on zero u get this clicking in the background, thru all 6 speakers, so im guessing that its pickin up on somethin or somethin is buggered
wat can yas tell me?
im thinking head deck
as the noises come thru all 6 speakers which are from 2 seperate amps so im thinkin its not gonna be a single amp. hmm i got no idea
plz help
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and whats the one thing that connects all thes amps and speakers? power 
alternator and battery.
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Location:
brisbane
Registered:
September 2005
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Re: stereo clipping and screech as turned off
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Sat, 12 November 2005 02:05
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so ur sayin all my problems should go away if i put a 'better' battery in? coz im gettin those noises with engine off, and a shit load more noises thru stereo with engine running, so if my alternator is rooted does that explain all this?
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I supported Toymods
Location:
Frankston, Victoria
Registered:
April 2004
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Re: stereo clipping and screech as turned off
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Sat, 12 November 2005 05:14
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Number one, wire your alarm off a seperate wire from the battery and disconnect it from ACC power, if both of those are joining, then you are constantly powering your ACC which is bad, and if unfused, can lead to fires...
Number two, your stereo system is having the same problem as mine has had all along in my KE70. The original stock KE70 stereo power wire was designed to power a shitty little radio unit... Barely enough to spin a CD on todays headunits. I am still yet to do it, but you should wire a direct 12Gauge wire from the battery to a relay, and use any wire from ACC (your old stereo power wire will be fine), to trigger it. Therefore giving your headunit the power it needs to spin the cd, light up its display, and put out 50W per channel.
I was so confused about that problem for so long, originally I thought it had to do with the wiring in my front speakers, because when I faded it to the back ones, the ticking/crackling/white noise would dissapear, then I realized that when I faded the headunit to the back speakers only, it would only be using half the power... Hence finding out the problem...
The reason it comes out through all your speakers (including amplified ones), is that your headunit is the thing making the noise due to being underpowered.
Kev.
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Location:
brisbane
Registered:
September 2005
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Re: stereo clipping and screech as turned off
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Sat, 12 November 2005 07:40
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ok i went and had a think today, and i figured that if it is voltage, its not gonna be there when i put the battery charger on it (i commonly do this when using stereo for a while without engine running) and i turn it on, gettin bout 13.8 volts across the battery, switch stereo on, what have we got, a shit load of mains noise 
phrostbyte i mite come talk to u some more
thanx for the help
~andrew~
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Location:
Penrith
Registered:
February 2005
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Re: stereo clipping+screech as turned off+background noises+HELP PLZ
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Mon, 14 November 2005 09:34
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mate, Try putting a wire onto the metal parts that are exposed on the RCA inputs of your amp then earth it to a seperate earth. Do this with the power off and do it for both amps. Just try holding it there or tapeing it to start with. It takes about 2 minutes to do and i almost garantee that it will fix your problem.
Cheers,
Kurt.
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Location:
brisbane
Registered:
September 2005
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Re: stereo clipping+screech as turned off+background noises+HELP PLZ
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Mon, 14 November 2005 09:42
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hmm how does this help? not tryna be a smart arse but am interested
well anyways update in progress i tried a mates deck and it was fine, and i tried my deck in mates car and is rooted, ive taken it in to be repaired and they reckon that its the rca tracks in the headdeck have been blown
they say it can happen if they get touched by a cable thats not insulated or if ur earths arnt strong enough, and i was having general earthing issues b4 this so it may well be
they gonna open her up tomorrow and ill hvae it back by wednesday, hopefully good as new
~andrew~
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I supported Toymods
Location:
Frankston, Victoria
Registered:
April 2004
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Re: stereo clipping+screech as turned off+background noises+HELP PLZ
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Mon, 14 November 2005 10:02
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| Kurt.R wrote on Mon, 14 November 2005 20:34 |
mate, Try putting a wire onto the metal parts that are exposed on the RCA inputs of your amp then earth it to a seperate earth. Do this with the power off and do it for both amps. Just try holding it there or tapeing it to start with. It takes about 2 minutes to do and i almost garantee that it will fix your problem.
Cheers,
Kurt.
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He actually has a point... If the amp isn't grounding the signal properly, it could be sending feedback back to the headunit.. I only noticed the problem in my car after I hooked up my amp...
Kev.
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Location:
brisbane
Registered:
September 2005
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Re: stereo clipping+screech as turned off+background noises+HELP PLZ
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Mon, 14 November 2005 10:33
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yeah i know
thats wat they say could have blown my rca tracks, if ur amp is struggling to earth it will go anywhere to find it, send a signal back up ur rca and BANG there goes ur headdeack rca tracks
i think the auto electricians mite touched somethin
but wat can i prove..
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Location:
Brisbane
Registered:
July 2005
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Re: stereo clipping+screech as turned off+background noises+HELP PLZ
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Tue, 15 November 2005 07:27
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| Phrostbyte wrote on Mon, 14 November 2005 21:02 |
| Kurt.R wrote on Mon, 14 November 2005 20:34 |
mate, Try putting a wire onto the metal parts that are exposed on the RCA inputs of your amp then earth it to a seperate earth. Do this with the power off and do it for both amps. Just try holding it there or tapeing it to start with. It takes about 2 minutes to do and i almost garantee that it will fix your problem.
Cheers,
Kurt.
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He actually has a point... If the amp isn't grounding the signal properly, it could be sending feedback back to the headunit.. I only noticed the problem in my car after I hooked up my amp...
Kev.
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As KE points out in the next post after this. Grounding an RCA cable EVER is a big bad idea.
Source unit will earth at point of least resistance. If you are having these kinda probs then there is a strong possibility of bad earths which is the WORST possible time to earth an RCA as it could very well fry ur unit.
I am not sure what you mean by the amp grounding the signal??? The circuitry for sound should NEVER be mixed with circuitry for power.
You could run all your speakers by earthing the negative lead behind the head unit and running one positive wire to the speaker, with the negative terminal of the speaker connected to your common earth (chassis) This would be an example of the dumbest noisiest system ever built.
KE - the head unit RCA earth is what i was gonna say as i was reading thru catchin up on this thread. However, phrostbyte's point about the factory power wire to the head is valid and is probably the cause of the head unit earthing through the RCA's. Fix that. You also MUST adress the alarm wiring - did you say with engine & stereo off, voltage keeps dropping? - if that is happening as you watch, then it will be a BIG cause of all this. And you MUST replace that battery as soon as you can. Your alternator is only suspect at this point in my view.
KE - check you PM's
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Location:
brisbane
Registered:
September 2005
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Re: stereo clipping+screech as turned off+background noises+HELP PLZ
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Tue, 15 November 2005 07:48
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ok...
this is gettin over my head lol
mic* when u say source unit wat are u meaning?
im thinkin this could have happened when the earth from my battery to chassis wasnt good enough, but i could be wrong, and im guessin the amps in search of an earth sent it up the rca's and kaput goes the head unit.
the earth on my head deck is slightly larger than the power input, which is rather piss weak, im thinkin about upgrading that.
the alarm system is all sorted now that ive disconnected the acc wire, coz i had used a piggy back connector and used the single acc wire for both, took the alarm one of, and it all works how its meant to, the led clock even turned off for the first time in 6 months!!! lol
no i said that with stereo on, ignition off voltage kept dropping, not surprising lol
why must i replace my battery?
it still works good :S
thanx for the help
mic* i get the headunit back tomorrow sometime, and if i need a hand i will give u a bell, thanx for the offer 
regards andrew
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Location:
Penrith
Registered:
February 2005
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Re: stereo clipping+screech as turned off+background noises+HELP PLZ
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Tue, 15 November 2005 09:19
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Earthing the RCA inputs on the amp helps to cut out noise caused by having slightly different voltages between earths caused by the different insulating properties of the car chassie(spelling?) and different size earth wires. It also helps if you can earth everything to the same point.
Phil, the owner of 5 Car Audio Excellence stores suggested this to me and it works a treat. The outside of the RCA lead is simply a reference for the signal which travels down the center. It just so happens that this reference is 0V i.e. earth.
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Location:
1st street on the right
Registered:
November 2002
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Re: stereo clipping+screech as turned off+background noises+HELP PLZ
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Tue, 15 November 2005 12:22
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1. For fucks sake fix the fucking alarm.
2. For fucks sake fix the fucking power the the head.
3. Running elecs on a car uing a charger to suuport it i the gheyest thing I've yet heard on thi forum. And I've read ome of the Artist formerly known as Bubbles work. It's not designed for this.
4. Oh and get the head fixed too.
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Location:
brisbane
Registered:
September 2005
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Location:
Kellyville, Sydney
Registered:
June 2004
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Re: stereo clipping+screech as turned off+background noises+HELP PLZ
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Tue, 15 November 2005 12:48
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| mic* wrote on Tue, 15 November 2005 18:27 |
You could run all your speakers by earthing the negative lead behind the head unit and running one positive wire to the speaker, with the negative terminal of the speaker connected to your common earth (chassis) This would be an example of the dumbest noisiest system ever built.
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thats how my 162 was wired up when i bought it. fek it was bad.
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Location:
Brisbane
Registered:
July 2005
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Re: stereo clipping+screech as turned off+background noises+HELP PLZ
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Wed, 16 November 2005 03:00
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| Kurt.R wrote on Tue, 15 November 2005 20:19 |
Earthing the RCA inputs on the amp helps to cut out noise caused by having slightly different voltages between earths caused by the different insulating properties of the car chassie(spelling?) and different size earth wires. It also helps if you can earth everything to the same point.
Phil, the owner of 5 Car Audio Excellence stores suggested this to me and it works a treat. The outside of the RCA lead is simply a reference for the signal which travels down the center. It just so happens that this reference is 0V i.e. earth.
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Do you actually understand what you have written???
I must be honest and say i dont really. Can you explain it any better or are you just relaying what Phil told you?
Dont get me wrong, i am not picking on you or calling bullshit, i jus wana understand the physics basis for why this would have a positive impact. Beleive it or not its not the first time ive heard of this being done.
As you described, RCA's have an outer sheath or wire. Call this a reference if you like, 0V, ie earth, -whatever- but that is where i lose you.
By definition voltage is the electromotive potential difference between two points. In this case the inner & outer RCA wires.
My understanding is the "signal" travels as an AC (alternating current) waveform down the centre wire, the outer "reference" serves to complete the circuit with the alternating current. Hence when there is signal (from source unit) and an amp connected, then there is a closed circuit and a voltage - a potential difference between inner and outer wires which causes current flow.
To then introduce the DC current which is running through your chassis into the circuit by cross connection...
How is that gonna help???
i understand that there is no path of lesser resistance through your RCA's for the amp or any other electrical component to earth current through, so in a correctly wired system doing this RCA thing should do nothing??? In a system suffering from bad power supply or bad earths tho... the possibility of DC current being pulled through these circuits is greater and should be prevented.
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Location:
Penrith
Registered:
February 2005
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Re: stereo clipping+screech as turned off+background noises+HELP PLZ
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Wed, 16 November 2005 09:14
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Yes I understand what I wrote, I studied electronics for years to become an Avionic technician (fix electronics on aircraft)
You are quite right with what you say about the signal from your deck being AC. What i'm talking about when i refer to the outer wire of an RCA connection being a 0V reference is this:
an AC signal looks like a sound wave, it go's up and down, + and -. This needs a reference other wise how will the amp know how high or low the signal is. I got the idea from Phil at CAE but he did not have to explain the reason behind it as I could tell straight away where he was coming from.
This can help fix problems in even the most technically perfect stereo install as there are other things to consider that may impact on the sound quality like a 'noisy alternator'.
any way i'm glad that your stereo is all fixed.
Cheers,
Kurt.
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Location:
brisbane
Registered:
September 2005
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Re: stereo clipping+screech as turned off+background noises+HELP PLZ
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Wed, 16 November 2005 09:33
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ok all this technical stuff may be handy when i get the headunit back
but at the moment its still not fixed because the dodgy bloody repairers didnt even to look at it in there 2 day turn around period, soo im hoping itll be back tomorrow and ill let everyone know how we go
cheers
~andrew~
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Location:
Brisbane
Registered:
July 2005
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Re: stereo clipping+screech as turned off+background noises+HELP PLZ
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Thu, 17 November 2005 01:22
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| Kurt.R wrote on Wed, 16 November 2005 20:14 |
Yes I understand what I wrote, I studied electronics for years to become an Avionic technician (fix electronics on aircraft)
You are quite right with what you say about the signal from your deck being AC. What i'm talking about when i refer to the outer wire of an RCA connection being a 0V reference is this:
an AC signal looks like a sound wave, it go's up and down, + and -. This needs a reference other wise how will the amp know how high or low the signal is. I got the idea from Phil at CAE but he did not have to explain the reason behind it as I could tell straight away where he was coming from.
This can help fix problems in even the most technically perfect stereo install as there are other things to consider that may impact on the sound quality like a 'noisy alternator'.
any way i'm glad that your stereo is all fixed.
Cheers,
Kurt.
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Ok, so i think what you are saying then is that the "reference" is the ground wire of the signal wire???
If so, then i agree, and thus my question remains. How does introducing noise, which is what you do when you connect anything to your chassis (which you amp is usually connected to), help???
What type of RCA's do you use? I think that may be where the answer lies. In a single core sheilded design, the outer sheath is the ground wire to the signal and any introduced current is noise that will be amplified. In a twin core sheilded design the outer sheath is sheilding which is connected to the ground wire at one point, but the ground and signal wires both run through the middle of the lead. Somehow this sheilds both wires from electromagnetic fields which would otherwise cause noise.
If you can explain more to me about RCA design then i think i mite understand you better, coz i dunno that much. If you have studied to be an Av-tech then you should be able to explain to me in electronics principles what earthing your RCA ground will do for you.
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Location:
Brisbane
Registered:
July 2005
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Re: stereo clipping+screech as turned off+background noises+HELP PLZ
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Thu, 17 November 2005 01:30
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| love ke70 wrote on Wed, 16 November 2005 20:33 |
ok all this technical stuff may be handy when i get the headunit back
but at the moment its still not fixed because the dodgy bloody repairers didnt even to look at it in there 2 day turn around period, soo im hoping itll be back tomorrow and ill let everyone know how we go
cheers
~andrew~
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Exceeding quoted time = kiss ass till you get your shit back then tell em to start chopping the bill or you wont pay anything.
If its a warranty job that sux. You can still have a hissy fit and threaten to call their supplier and tell what sort of an image they're giving the product.
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Location:
brisbane
Registered:
September 2005
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Re: stereo clipping+screech as turned off+background noises+HELP PLZ
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Thu, 17 November 2005 01:34
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yeah, im goin to pick it up soon, got a call from them earlier, they were apologetic coz they had a coupla 'sticky jobs' yesterday, wateva that means
lol
anyways she should be all up and goin b4 the formal tonight, shame i dont have my license
anyways thanx for the help
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