Sound system

Submitted: Monday, Dec 25, 2017 at 00:41
ThreadID: 136017 Views:1849 Replies:8 FollowUps:3
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Hi, I am having some trouble replacing some speakers in my 80 series ,
Does anyone know what it means if ur rear speakers were working but then just cut out, but the front speakers and CD player and lights are all working?
Ps I mite have arched out a wire when hooking it up
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Reply By: Mick O - Monday, Dec 25, 2017 at 11:08

Monday, Dec 25, 2017 at 11:08
If they work intermittently then I'd say it's probably a wiring issue including connection to the rear of the stereo unit or to the speakers. You may need to retrace the wiring and check it. You could have also blown the speakers. Have you run a multimeter over the speaker wires to see if they will conduct current? If they do, it may be an issue at the speaker end.

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trip would doubtless be attended with much hardship.''
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Reply By: Micheal T - Monday, Dec 25, 2017 at 23:00

Monday, Dec 25, 2017 at 23:00
They just cut out , and no power in the wire straight from the head deck
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Reply By: Allan B (Sunshine Coast) - Tuesday, Dec 26, 2017 at 12:34

Tuesday, Dec 26, 2017 at 12:34
Hi Micheal,

Tell us a bit more about "mite have arched out a wire when hooking it up".
Provided that the radio was turned off while you were connecting the speakers it is unlikely that you caused any harm. If the front speakers are still working the head unit is probably still OK.

Were the rear speakers playing music before they cut out? Did they cut out together?

Are the speakers suitable for car-radio use? Are they specified as "4 Ohm" impedance?

Was the rear speaker wiring existing or did you run new wiring?


It is just possible that you have inadvertently changed the radio's settings to mute or reduce the volume settings of the rear speakers while leaving the front speakers at full volume. To check this you would need to go into the radio's settings and look for "Balance" or similar. There will be options for Left/Right and Front/Rear settings. Refer to the User Manual if you have it or search online for it.
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Allan

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Follow Up By: Shaker - Tuesday, Dec 26, 2017 at 13:32

Tuesday, Dec 26, 2017 at 13:32
I am pretty sure that front to rear balance is ‘fade’, I wasn going to suggest that but it seemed a bit too basic, although we have overlooked the obvious at times!

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Reply By: Micheal T - Wednesday, Dec 27, 2017 at 15:30

Wednesday, Dec 27, 2017 at 15:30
Radio was on , rear door speakers were working , taped into right hand rear door speaker wires to add a new speaker in the back, and I think the wire arched on the tailgate as I grab it to hook it up
AnswerID: 615720

Reply By: Micheal T - Wednesday, Dec 27, 2017 at 15:43

Wednesday, Dec 27, 2017 at 15:43
Speakers are 4 ohm
AnswerID: 615721

Reply By: Allan B (Sunshine Coast) - Wednesday, Dec 27, 2017 at 16:23

Wednesday, Dec 27, 2017 at 16:23
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If the speakers were "on" i.e.operating, whilst you were wiring up, and you "arced" it, then there is a good chance that you blew-up one of the output transistors. Although the effect of that would have been immediate. If so it will be a technician repair job.

Also, connecting an additional 4 Ohm speaker in parallel with an existing 4 Ohm speaker produces a 2 Ohm load on the radio output stage which the radio may not like very much! Probably same result as above!

Cheers
Allan

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Reply By: Bob Y. - Qld - Wednesday, Dec 27, 2017 at 18:14

Wednesday, Dec 27, 2017 at 18:14
Slip down to JB Hifi, Michael, before 1/01/18, as they are having a 30% off sale on some pretty impressive head units. I'd say you might need one...........and turn the unit off next time before working on it, eh!

Bob

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Can't remember most of it.

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Follow Up By: Allan B (Sunshine Coast) - Wednesday, Dec 27, 2017 at 19:27

Wednesday, Dec 27, 2017 at 19:27
.
Good idea Bob. And thanks for putting the warning more directly than I did!

And one more bit of un-needed advice Micheal....... don't try to connect additional speakers to a radio that is not designed for it or you may be back at JB HiFi for a second time. lol
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Allan

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Reply By: Micheal T - Friday, Dec 29, 2017 at 13:51

Friday, Dec 29, 2017 at 13:51
Ok thanks guys , haha yeah I won't be risking that again.
What's the best way to add another speaker with out adding extra load to the new head unit?
AnswerID: 615771

Follow Up By: Allan B (Sunshine Coast) - Friday, Dec 29, 2017 at 15:14

Friday, Dec 29, 2017 at 15:14
.
Hi Michael, OK, a short course in Ohms Law, or at least, speaker connection.

Radios, like many things, are rated to support specific loads and if exceeded may cause problems. Typically, car radios are designed to have 4 Ohm speakers (there are exceptions). 4 Ohms is the 'impedance' (similar to electrical resistance) of the speaker winding. The lower the impedance number, the more load it will consume so if you connect two 4 Ohm speakers in parallel it will become a 2 Ohm load trying to draw twice the original power and that may be too much for the radio output stage.

You could use two 8 Ohm speakers in parallel which becomes a 4 Ohm load which would be safe but will now only deliver one half of the former power (loudness) from each of the speakers. Similarly, you could wire two 4 Ohm speakers in series but again will now get half the former power from each speaker.

Of course, you can probably simply turn the volume up to compensate for the impedance change, but in your case where I understand that you are only adding a speaker to one channel, doing the above arrangement would produce a L/R channel imbalance. Trying to use the balance control to compensate would unbalance your front speakers.

Soooo, here is what you may wish to try................
Let's assume you want the additional speaker on the Right channel. Take the existing Left 4 Ohm speaker and wire it in series with the existing Right 4 Ohm speaker, creating an 8 Ohm load. Use a new 8 Ohm speaker for the Left channel. You now have an 8 Ohm load on each channel but you will have to turn the volume up to compensate and that upsets your front/rear balance although you may be able to adjust the radio Setup to rebalance front/rear.

The other (and better) way is to add two new 4 Ohm speakers placing them in series with the existing Right and Left 4 Ohm speakers. Each channel is now 8 Ohms so there will still be the front/rear balance issue.

The front/rear balance thing may not bother you too much if a lower volume at the rear is acceptable.

Now a note about connection. Speakers are 'polarity' conscious. Not quite in the same sense as batteries but they do need to be connected correctly or you will have 'phase imbalance'. This will cause poor output and strange acoustic effects for the listener.
Speaker cones 'push out' and 'retract' alternately to create sound and it is important that they do so in unison. Each speaker's terminals are marked with a positive and negative sign.
If connecting speakers in parallel join the positives on each speaker together and the same for negatives.
If connecting speakers in series, remove the original wire from the negative of the first speaker, join the negative terminal of the first speaker to the positive of the second speaker, then wire the negative of the second speaker to the wire you removed from the first speaker. If you need, sing out and I'll put up a diagram.

Now, after all that, there is the really correct way to do it but it requires installing a small secondary amplifier for the additional speakers and I figure you don't want to go there!
Cheers
Allan

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