Car audio problems.

_HighVoltage_

Captain Volvo
Joined
Aug 5, 2006
Messages
9,964
Car(s)
1998 Volvo S70 T5M
My Volvo originally has the premium sound system at the time, which had 8 speakers. Unfortunately, 4 of them are no longer working.

I want to put two new speakers on the rear deck. Here is the problem though: Volvo connected the 4 rear speakers parallel (2x2). The stock head unit, and my aftermarket unit have output impedance of 4 oHm. To make the speakers work properly, they put in 8 oHm speakers, which connected in parallel give a total impedence of 4 Ohm.
From what I've seen on the market, most speakers are either 4 oHm or even 2 Ohm. I'm afraid that if I put a set of these I will blow my amp. Am I right?
Because each of the new speakers will be connected to one of the old. So an 8 Ohm speaker will be in pair with a 4 oHm or even less...

Does anybody know a pair of 8 oHm speakers?
If not...just in general which brand would you recommend? (Something cheap yet not crap) I'm currently looking at Alpine, because my head unit is Alpine.
 
I would suggest going to the12volt.com and asking them.
 
AFAIK you should be alright, especially with an aftermarket HU. However, I haven't played with many odd-impedence systems, so YMMV. Personally, I'd just spend the extra hour and fix the wiring (and of course replace the other set as well)
 
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Sounds like they put in house speakers instead of car speakers.
 
Well, it's built by Swedes...enough said.
I just opened the speakers on a VW Passat and they are 3ohm. It's an odd number, but still...much better than 8.

I really don't want to mess with the wiring. I just hope that a pair of 3.6oHm speakers will work fine and won't blow the amp.

By the way, the situation is exactly the same up front - 2 working, 2 not working.
 
Before you start buying speakers, check to see if there is any power getting to the wiring for those speakers. You can use any speaker that is working without problems. Or check to see if the speaker is good, you can do this with a volt/ohm meter or a 9 volt battery will make it jump. But I am willing to bet that you have a wiring problem behind your radio.
 
Careful with the ohms. If you put a too low ohm load on an amplifier, it may become terribly hot in best case and die and burn in worst case. If Volvo designed it for 4 ohm load max, you shouldn't go lower than that. What size (diameter) of drivers are you looking into putting into the car? I might be able to provide help.

As for 3 ohm speakers from VW: manufacturers tend to go for low ohm figures because of the natural 12V limitation in cars. They make sure the amp can cope with that however, so one should not connect speakers with a lower impedance (= lower ohm figure).
 
Before you start buying speakers, check to see if there is any power getting to the wiring for those speakers. You can use any speaker that is working without problems. Or check to see if the speaker is good, you can do this with a volt/ohm meter or a 9 volt battery will make it jump. But I am willing to bet that you have a wiring problem behind your radio.
Wires are good. Connected a working speaker on each wire and it works at each one.

Careful with the ohms. If you put a too low ohm load on an amplifier, it may become terribly hot in best case and die and burn in worst case. If Volvo designed it for 4 ohm load max, you shouldn't go lower than that. What size (diameter) of drivers are you looking into putting into the car? I might be able to provide help.

I'm not using the stock radio. I have a Alpine aftermarket unit (4 Ohm again). Do you have any idea how low is too low?

(I don't know what you mean by "drivers"...what is that?)
 
Really dude, just go into the doors and convert from parallel to series wiring. It'll take all of like 5 minutes once you get the door apart. A 12ohm equivalent (the existing 8ohm + the new 4ohm) should be well within the design parameters of any aftermarket head unit. (16 is usually a good rule of thumb). It won't sound brilliant (unless you also swap the door speakers to 4ohm) but it'll work.
 
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This is what I plan to install:
A pair of Alpine 6x9 inch speakers
5/8" poly dome tweeter and 1" silk dome midrange
power range: 2-85 watts RMS (260 watts peak power)
Impedance: 3.6 Ohm


I would like to convert the wiring, but I have no idea how to do that...it's been way too long since I studied electricty circuits in high school.
 
At the speakers in the door, you'll find that there's a pair of lines that connects to each of the + and - terminals and passes on to the deck speaker. Just reconfigure the wiring at the door speaker so a wire comes in to the + , and out the -, on to the deck speaker's +. From the deck speaker's -, you should go all the way back to the HU. Essentially, you want the loop to pass through both speakers, and back, instead of touching the middle speaker twice.

You have this (top half):
image34.gif

You want this (top half):
image33.gif
 
I'm not using the stock radio. I have a Alpine aftermarket unit (4 Ohm again). Do you have any idea how low is too low?
Well, the specifications say that a 4 ohm amp must be able to cope with an impedance down to 3.2 ohms. So your amp should be able to live with that.
At the speakers in the door, you'll find that there's a pair of lines that connects to each of the + and - terminals and passes on to the deck speaker. Just reconfigure the wiring at the door speaker so a wire comes in to the + , and out the -, on to the deck speaker's +. From the deck speaker's -, you should go all the way back to the HU. Essentially, you want the loop to pass through both speakers, and back, instead of touching the middle speaker twice.

You have this (top half):
image34.gif

You want this (top half):
image33.gif
This is the easiest solution. Go from parallel to serial, and your impedance (= the ohms) doubles instead of halves. You lose some SPL in comparison to parallel, but your amp will thank you. If the drivers will not be identical though, they will not sound as itended in this configuration (I apologise in advance: it will be a frequency-dependent potential-divider). Thus, this technically works, but is in no way optimal.
 
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Thanks for the help guys. But isn't too high impedance create too much distortion in the sound? If I make a series connection, I'll be looking at 12 Ohm per channel... (as opposed to 2.66 in parallel)

What I think I'll do is just get a nice pair of 4 Ohm speakers and simply disconnect the door speakers (they kinda suck anyways. Plus, the sound projection from the rear window should create a much better overall sound.
But the rear deck speakers will still work, if I disconnect the door speakers...right? (once again they are in parallel)
 
Thanks for the help guys. But isn't too high impedance create too much distortion in the sound? If I make a series connection, I'll be looking at 12 Ohm per channel... (as opposed to 2.66 in parallel)
No, high impedance doesn't create any distortion. It just limits the amps that can go through your speaker at a given voltage, so when your amp makes say 100W on a 4 Ohm speaker, it may only deliver 30W on a 12 ohm load. No danger involved, just inconvenience.
What I think I'll do is just get a nice pair of 4 Ohm speakers and simply disconnect the door speakers (they kinda suck anyways. Plus, the sound projection from the rear window should create a much better overall sound.
But the rear deck speakers will still work, if I disconnect the door speakers...right? (once again they are in parallel)
That'll work fine. And no, taking out the speakers in the doors will not cut your connection to the back, since they are parallel.
 
Ok, that's settled then. I'll just put two new speakers and disconnect the old ones for the moment. Maybe later I will do the series connection.

Now here comes the question of brand. Right now I'm in between Alpine, Pioneer and Kenwood. There is also a set of Sony Xplod for $20...so which one is best?
(I'm keeping things really cheap, because the car needs much more important stuff than speakers)
 
Doesn't really matter, since the cheap 6*9 stuff all is pretty bad. :p
 
Ok, that's settled then. I'll just put two new speakers and disconnect the old ones for the moment. Maybe later I will do the series connection.

Now here comes the question of brand. Right now I'm in between Alpine, Pioneer and Kenwood. There is also a set of Sony Xplod for $20...so which one is best?
(I'm keeping things really cheap, because the car needs much more important stuff than speakers)

Avoid the Xplod. The Walmart house brand speakers at that price point are better, and that's not saying much. The Alpines are probably the best of the lot in the budget segment.
 
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