DAZ 4

I have just removed the (front) door panels and am fitting new (JBL) speakers. I have cut the wires leaving the connection plug intact on the door (I hope that makes sense). The question I need answering is :

What colour wires are positive and negative, I've looked at the old speakers and can't see a + or - sign on them (the new ones have).



[This message has been edited by DAZ 4 (edited 14 November 2000).]

chiark

Daz,

Sorry for not knowing the answer, but if you find out could you let me know so that I could update the FAQ?

You may be able to find the standard for + and - somewhere on the web given that the Subaru speaker connector is a standard used by most Japanese cars, apparently. Someone somewhere will have it on their website.

Cheers,

Nick.

harryh

Have you tried using a multimeter to determine which is which?

DAZ 4

Chiark,

I did a search and the colours were different to the ones I was talking about. Excellent website by the way, used it to take the door panels off (quickly).

I found that the component tweeters (JBL) fitted nicely behind the blank tweeter panels by using foam insulation strips Also 6 1/2" JBL's fit into the enclosures, but the plastic spacer could not be used I had to make some MDF ones. Be careful if you need to use longer screws, if they protrude too far the window catches on the way down (not a pleasant sound !!)

Harryh,

I was aware that you could do that but didn't know how

In the end I connected what sounded right (there didn't seem to be much difference).

[This message has been edited by DAZ 4 (edited 15 November 2000).]

Scooby Doc

Hey Daz 4

As a matter of interst, what was the website?

Martin

DAZ 4

Scooby Doc

harryh

Daz, I think (I'm sure somebody will correct me if I'm wrong ) that it only matters that you connect both speakers the same way round and not one each way round (if that makes any sense)

mattski

you could always put them in, if it sounds
cr*p (i.e. no bass) they are probably wired
up incorrectly...not that I have done that of course

oh, Harry... you are wrong cos they will
be out of phase i.e. pushing when the should
be pulling etc

harryh

Thanks Mattski, suppose I must've been lucky to get all the speakers I've ever plugged in the right way round then.

DAZ 4

mattski / harryh

I tried them both ways round and couldn't notice a difference !! Perhaps because they are component speakers ??

I think your right about the push / pull thing though.

chiark

The push/pull dowsn't matter as long as both speakers are pushing/pulling at the same time, respectively. Even if you get them out of phase, in some cars this sounds better, though I haven't really experimented with the scoob. My astra had the mids out of phase as that sounded better for no explainable reason...

An amplifier provides a true AC signal, and speakers move both "in" and "out" from their at rest position, meaning you can't damage 'em. The most common way of damaging a speaker is by playing a small amplifier too loud, sending it into clipping (ie producing dc for a certain amount of time). There's no way a speaker can reproduce DC, so it just heats up the voicecoil, leading to *pop*...

DAZ 4

The expert has spoken

chiark

I was about to say "definitely no expert, just an interested geek", but then saw the grin . Just to clear it, I'm certainly not trying to position myself as an expert

Richard Gledhill

Normally if you connect them up out of phase, the bass vanishes - test by fading slowly from left to both to right, on a bassy track.

Also, if you look back at your original speaker, you may find that one of the spade terminals is larger - this is normally negative, though I can't remember for sure Also, if one of the wires is black or has a black stripe on it, that normally means negative too.

Good luck!
R

Adam M

Hello,

Right.

At the point b4 the passives, it does not matter if they are the wrong way round so long as they both are. Equally it is possible that it will sound better with one out of phase. Best thig to do is see what sounds best. It is a common thing to have off axis omponent speakers (separate tweeters and mids). Some people will intentionally knock one mid out of phase as it shifts the sound stage.

The sound generated by both speakers creates and interference field related to the acoustics of the car and the signal being put out by the speakers. This consists of maxima and minima in the intensity of the sound (volume). Anything you do to move the sound field may mean that you have moved from sitting in a maximum to sitting in a minimum, hence it will get quieter.


This is a very simplified model of what is happening as obviously the speakers are emitting plenty of frequencies. Each frequency will have its own intereference field, thye most audible being the bass.

Ignoring the complexity, wiring one mid out of phase is equivalent to moving your head to a different positing. So getting it wrong isn't an issue. It is entirely dependent on you position and the car itself.

Trial and error my friends is the best way.


May the force be with you

Adam M

.Hello,

Right.

At the point b4 the passives, it does not matter if they are the wrong way round.It is possible that it will sound better with one out of phase. Best thing to do is see what sounds best. It is a common thing to have off axis component speakers (separate tweeters and mids)with one mid knocked out of phase as it shifts the sound stage.

The sound generated by both speakers creates and interference field related to the acoustics of the car and the signal being put out by the speakers. This consists of maxima and minima in the intensity of the sound (volume). Anything you do to move the sound field may mean that you have moved from sitting in a maximum to sitting in a minimum, hence it will get quieter.


This is a very simplified model of what is happening as obviously the speakers are emitting plenty of frequencies. Each frequency will have its own intereference field, the most audible being the bass.

Ignoring the complexity, wiring one mid out of phase is equivalent to moving your head to a different position. So getting it wrong isn't an issue. It is entirely dependent on your position in the car.

Trial and error my friends is the best way.


May the force be with you .

[This message has been edited by Adam M (edited 17 November 2000).]

ptholt

You mean to say you are putting in decent speakers only to ruin the sound by using factory fit cable........

surely thats not a good idea?

NAF

Guys,
Would I be correct in saying that the red wire is the negative as its the common colour wire on both channels....?????

Or could I be completly wrong as usual

Niall

Richard Gledhill

Sounds highly likely! Another way is to pull out the head unit, and look in the wiring loom coming out of the back. Should be able to find pin-outs for ISO connectors on the net somewhere.

Adam M - basically true, but it's a little more complex than that. If you were a pin-head then that would be spot on. The trouble is there's about 8" between our ears, and the human ears are very sensitive to things being in/out of phase - that's how we detect whether things are in front or behind us etc. Having the speakers wired out of phase can make the sound wider but can also induce headaches and sound uncomfortable (I think someone on another thread had this problem and it's only just occurred to me why!).

If you have a tame car hi-fi dealer, get them to swap the connections on one of the speakers on the display and see what it sounds like.... horrible to my mind

Richard

mattski

anti-flame device on...

the phase does matter, the signal from the
source ultimately dictates what 'way' the
speaker is supposed to be driven and if
they are wired up the wrong way round then
it *does* make a difference.

I had a mate who worked at a very high end
recording studio (including big name artists) and it definately does make a difference. They make sure everything is in phase as a matter of course so if them guys do it we only go and naff up all of their hard work if we get stuff out of phase.

so there :OP

ScoobyDoo555

Hey Mattski,
Who was your mate? Which studio did he work at?

mattski

he swore me to secrecy, although.......
he did music for the film the Lost Boys, Cold Cuts last album etc etc... music
kinda runs in the family, my dad is the
drummer for Banco De Gaia and does lots
of studio/live stuff. I dabled in sound
engineering for a few years too...

check out Banco, tis pretty good
if you like dancey/trancey stuff

chiark

Mattski: I stand corrected. Cheers! My ears wouldn't be good enough to hear this, I'm sure, but I'll give it a try at home tonight. Problem is I can't perform a double blind test so it'll be psychological more than anything else...

Richard: I've heard the same speakers, in phase and out of phase on a blind test and preferred the mids being out of phase. This was in a Volvo 480, admittedly, with CD Technologies high end speakers. We checked all the way back to the amp that the phasing was actually as we thought, and it was...

Strange but true.

DAZ 4

Chiark/Mattski/Richard/Others !!,

After fitting the Kenwood (6080)head unit and JBL (GTO 65-0c) component speakers, there seems to be a lack of base at the front. Could this be due to the fact that the head unit is not powerful to power the component speakers ? Or could the spacers that I made up from MDF have anything to do with it ?

Any thoughts would be greatly appreciated.

chiark

Or it could be that they're out of phase as this is the classic way of telling that something is wrong. Adjust your balance to all one side and then move it to centre: does the bass get louder or quieter? If quieter, you're out of phase.

Your head unit should be powerful enough to give decent-ish bass reproduction. Are you comparing to the standard head unit and speakers and finding less? If so, something is wrong.

Are your MDF baffles providing a seal between the front of the speakers and the back?

DAZ 4

Chiark,

They seem to be less bassy at the front than the back now (although a lot clearer in the treble). I will check the MDF "rings", I Know on the plastic original ones they had a rubber mastic on them.

Richard Gledhill

Check the sealing as Chiark said - if the speakers aren't sealed, then the sound gets affected by the reflection coming back from the inside door panel, and cancels out some of the bass. Also, I think the original fit speakers have baffles on them to help prevent this, though I might be thinking of my old car. I've changed the ones in the Scoob twice now!

Richard

DAZ 4

Richard,

You are right the plastic ones I took out had a type of "shield" built in. I couldn't use these as the JBL's were too deep. I'll try and think of an alternative.

Adam M

I think you have missed the point somewhat. What I said above was an attempt to massively simplify something that is much more complicated. Oversimplifying was not my intention.

The point in plain english to try to get the thing in phase initially. If it doesnt sound quite right, or even if it does, try knocking a mid out of phase and listen to the difference. If better greta, if worse change it back. It is entirely subjective and dependent on your ears alone.

Comparisons with a studio are entirely out of place here as the sound environment of a car is as bad as listening through a pillow. Imaging in a studio is easy to achieve by comparison but in this situation fortunes are spent on every other aspect of the system.

My home hifi uses four runs of speaker cable each of identical length, the banana plugs are changed every three months to maintain contact intgerity. The cabling costs more than the amplifiers in my car system.

To put it bluntly forget what you learn from home audio, it is an entirely different ball game.

DAZ 4

q

[This message has been edited by DAZ 4 (edited 24 November 2000).]