16 replies to this topic

[Marlin]

What does everyone think about this statement
"Shame your installer used twisted pair wire. This stuff is for ballance line transmission. If used like ordinary RCA lead then it acts like a bloody high-gain antenna picking up noise...."
in reference to RF Helix twisted pair RCAs.

[Big_B]

Slap the person, or tell them to slap themself, & then tell them to go back & do high school physics again.

Or, provided that there's no noise in your system, query them why there's no noise in your system if twisted pair cable makes such a good "antenna"

[Marlin]

LOL the person who told me this is on the street commodores forums apparently according to himself hes a self stlyed car audio guru/specialist installer, stupid git.

[nemesis]

wow, so that must be why the last 3 cars ive put them into all have zero noise but i can pickup military talkback

[Macca]

Re Direct him to the THOUSANDS of CAA threds reguarding RCA's

[Marlin]

LOL I did I told him to come on here and make those claims

[bob]

eEk. Just think of all the cat5 fitted to buildings and stuff for networking. They have huge antennas now!!

[Marlin]

If anyone feels like contining this arguement on the SC froums please feel free to do so it was quite entertaining.

[Maz]

What that guy said is 100% correct.

Proof to why twsited rca's are for Balanced outputs only

So yea everyone on here is wrong i guess

[ November 02, 2003, 23:43: Message edited by: Maz ]

[Shieldsy]

Very interesting read there maz.
interesting indeed

[Marlin]

Well there seems to be a bit of confusion to what is correct or not since shielded RCAs are supposed to be useless as well does this mean I should just buy 5 dollar Aerpro RCAs? Personally I think the person in question on the SC forums is very arrogant he sent me several PMs saying basically I'm a Fu*kwit for daring to disagree with him I have met several people like him who work in this industry who think their the ducks nuts and usually they are full of sh*t anyway I have been told by alot of people such as installers and SQ freaks that running power cables next to the ECU in a commodore will induce noise whats everyones thoughts on this I believe it to be true as I did this and had a horrific noise problem stragely enough it was only out the rear speakers.

[Marlin]

Quote

Originally posted by Maz:
What that guy said is 100% correct.

Proof to why twsited rca's are for Balanced outputs only

So yea everyone on here is wrong i guess    

Becareful about what you read on the net this is just his opinion I sure that someone else has a similiar article with "test results" as to why you should use twisted pair RCAs. What qualifcations does this person have to make these claims does he know how to use the test equipment or calibrate it properly also the use of high voltage neons to induce noise is meaningless for car audio since noise in a car is induced from large DC currents (eg. from the power cable) which I imagine would have completely different EMF properties to High voltage low current AC (any physicists here I'm a chemist) and the whole idea of this being some giant conspiracy on the cable manufactors part is just plain silly.

[EAspeed]

i can see hear that people have compared copper wired utp (unshielded twisted pair) cable (Cat5e for example) that are used for computer networks that has 4 pairs, if using full duplex mode on network then 2 are used for each way of transmition with the current being turned on and off, with the emf created by the pairs havin to directions it created a sort of shield around the cable, as it has to put up with 240v for ur household power. and in high quality rca cable used in car audio are made of a lot high quality products the signals that they transmit are of a constant current of varying voltages, and each wire carry similar but not always the same voltage, for this reason i believe that they are twisited but rca's also have a shielding round them that protect from noise, thats why in have noise areas of computer networks they use STP (shielded twisited pair). but its costs are **** loads more than UTP so thats why it is not used more often.

these are just my thought, so if i am wrong and there is most likey a high degree that i am please feel free to correct me.

ben

[PFX]

i've done a little physics, but it's pretty sketchy now..

the strength of an emf is directly proportional to the CURRENT carried, not the voltage. the strength also decreases inversely proportionally to distance, ie for every equal distance you move away, the power of the emf is reduced by 1/2

from my point of view, buying 'shielded' rca's is pointless. emf's are extemely difficult to eliminate, and no material can physically block the field, without the field being attracted to it (in the case of rca's, the shielding is on the cable conducting the audio signal, hence the emf is induced into the shielding AND the signal cable)

for further detail read:
http://www.magnetic-shield.com/faq/faq.html

i'm sure a lot of people will like to disagree, but it's a very controverisal topic (it's like saying mobile phones cause cancer [although it has been found that there is no direct link, and the cause is either non-existant or indirect])

anyway, i shall leave you to ponder

alex

[Marlin]

Anyone else got any thoughts