Testing Polarity

[harley 0]

Hi, treid a search and been trawling through the forum but no luck so far!

 

Basically the previous owner has uprgraded the speakers in my car, they seem quite decent too with JL 6x9s in the back and some pioneer coaxials up front. Also a pioneer head unit. It looks like he has also had a sub intalled which he has taken out before he sold it.

 

However, the 6x9s can handle absolutely no bass whatsoever and the fronts aren't doing much better! I'm not after mega volume or silly bass but at the moment I can barely put any power through without atleast one of the speakers crackling.

 

I've been told I need to test the polarity on all the speakers because if one is wrong then that would throw the whole system out. Is this true?

 

So should be getting my hands on a mate's multimeter tomorrow but I am like a caveman when it comes to electronics so if anybody has any advice or a guide on how to do this it would be very appreciated!

 

Thanks in advance, Harley

Edited January 30, 2010 by harley

[Craig89 0]

Incorrect polarity basically means that they are wired incorrectly and the wires are going to the wrong terminals on the speakers but im no real expert with sound systems so i couldnt really advise you where to start, other than to pull the head unit and speakers out and just to check to see if there are any wires loose or if the wiring is messy?

 

Good luck

[lagonda 42]

Pretty certain that speakers aren't polarity-dependent, although accept speaker wiring is generally coded...assumed this was just to keep people happy that thought polarity mattered.

 

More likely, I would have thought, that diaphragms have torn (like they have in the original speakers in my CTi) due to too much power for too long. That would certainly cause your symptoms.

[Wes 86 1 Cars]

of course speakers are polarity sensitive. if one is the wrong way round it will sound like the bass is cancelled out. you can determin this by fading left to right, if the sound gets bassier when only one speaker is on then the polarity is wrong on one of them. its just a simple case of looking at the wires behind the head unit and speaker. the negative wires from the head unit have a black line on them. fronts are grey and white and rears are purple and green. hope that helps.

[harley 0]

you can determin this by fading left to right, if the sound gets bassier when only one speaker is on then the polarity is wrong on one of them.

 

yeah that is another of the symptoms! I'll have a go at it tomorrow and let you know how i get on.

 

Thanks for the help

[DrSarty 90 1 Cars]

Yes polarity is important. Incorrect polarity reduces bass performance, and - if you're that way inclined - messes up the sound stage.

 

For example a person's voice sounds totally different if out of phase. Out of phase means the speaker is moving in when it should be moving out, and vice versa.

 

Speakers wired in phase, have the positive output from the amplifier going to the positive input terminal/tab of the speaker. This is why speaker wires (the pairs) have one wire marked. Whether you choose the marked wire as positive or negative is up to you, as long as polarity is the same at both ends.

 

Different manufacturers, for example Sony v Pioneer have chosen marked (striped) wires differently, so one had striped wire meaning negative; the other has it as positive. I'm sure you can figure it out; it's not complicated.

 

Anyway: to answer the original question, an actual simple, physical test for testing the polarity of a speaker itself is to use a 1.5v battery (yes, just a normal torch type battery) with two wires attached, one to each +ve and -ve terminal.

 

(This test is done if it's not obviously marked which speaker terminal is which. When marked, +ve speaker terminals are either marked with a plus sign, or with a red blob of paint, which often means the -ve terminal isn't marked at all. There's no need to do this test if the speaker is marked; you only need to wire them with the correct polarity.)

 

Attach the -ve battery wire to a speaker terminal firmly (so you can let go and they stay attached), and then just touch the other wire to the other (+ve) speaker terminal.

 

If the speaker cone moves outwards (away from the magnet at the rear), then you have matched +ve battery terminal to +ve speaker terminal.

 

If it move inwards, then you have it wired in reverse (i.e. +ve battery terminal to -ve speaker terminal), aka out of phase.

 

Mark the positive terminal clearly for future reference.

 

Edited January 31, 2010 by DrSarty

[lagonda 42]

oooo errrr learn something new every day!

[harley 0]

So I think I got everything connected up the right way now, the speakers are sounding a lot better!

 

There's still a lot of rattling and crackling but I'm going to hazard a guess that it's just my 205 being a 205!

 

Sound deadening is now on the Christmas list!

[DrSarty 90 1 Cars]

So I think I got everything connected up the right way now, the speakers are sounding a lot better!

 

There's still a lot of rattling and crackling but I'm going to hazard a guess that it's just my 205 being a 205!

 

Sound deadening is now on the Christmas list!

 

That's good and bad.

 

There should be no rattling and crackling. You most likely have the volume turned up too loud - which might make you laugh or say 'pfft' - but it's the amplifier in the head unit that's most likely distorting and not the speakers. This is a common misconception.

 

Check the condition of all of the speakers, as a split cone will sound crud.

 

You don't have something right; whether that's the way it's installed, the condition of the items or your expectations of what it can produce.

[harley 0]

I do have a 1cm crack in one of the 6X9s which will obviously be affecting things slightly, but none of the rattles seem to come from that speaker!?

 

Also, some of the screws holding the speakers into the door cards just keep on turning and don't tighten up so I reckon that could be another cause of a slight vibration when volume increases a bit!

 

There isn't really any distortion in the quality when the volume is up. I never have it too loud anyway, but scabbed a better head unit off a mate and there is definitely an improvement.

 

What I was getting at though is that I think the speakers and doing there job now, I'm just getting the same problem I used to have with my saxo where the french interior panels like to dance along to the music! I can live with that though.

[DrSarty 90 1 Cars]

Installation IS the key. Screw everything down/in properly.

 

You will enjoy everything much more then.

[gowmonster 2]

Installation IS the key. Screw everything down/in properly.

 

You will enjoy everything much more then.

 

are the speaker cables unsheilded? did you say an amp was involved? do the cables run along side an amp cable? if so it could be interference.

[harley 0]

No amp involved so not interference.

 

If the screws are turning and not tightening up completely, how should I go about sorting this?

 

Is it good enough to just buy some slightly thicker screws?

[2-Pugs 57]

Attach the -ve battery wire to a speaker terminal firmly (so you can let go and they stay attached), and then just touch the other wire to the other (+ve) speaker terminal.

 

If the speaker cone moves outwards (away from the magnet at the rear), then you have matched +ve battery terminal to +ve speaker terminal.

 

If it move inwards, then you have it wired in reverse (i.e. +ve battery terminal to -ve speaker terminal), aka out of phase.

 

Mark the positive terminal clearly for future reference.

 

 

Thats a very handy tip. I will remember that one for the future, will no doubt come in handy

 

No amp involved so not interference.

 

If the screws are turning and not tightening up completely, how should I go about sorting this?

 

Is it good enough to just buy some slightly thicker screws?

 

Yes you could use some slightly larger screws to tighten it all up. You could also try also using some of that foam tape stuff or similiar underneath the various bits of trim to dampen down any vibrations.

 

I would check your speaker wires, particularly to the rear speakers. Make sure you have used decent quality wire, that your joins are good, and that the speaker wire doesn't go alongside or close to any power wires which could cause interference.

 

The other thing worth checking is that you have a decent earth to your headunit as a crappy connecion can result in electrical noise.

[Cameron 16]

You could rivet them in if you're feeling lazy, and don't need them out in a hurry.

 

Good info there Dr Sarty!