Rear speakers not working

[dave c]

Hi,


Looking for a bit of help. I've just fitted two rear speakers but theres no sound.


Tried all the HU balance stuff but nowt coming through.

My headunit was installed years ago by a company up north and the setup was always as follows:

Amped 6x9's in the boot,

Amped components w/tweeters in the front doors,

No rear,


It sounds fine but I had some speakers lying around so I thought i'd try them out. I assumed I would be able to power these rear speakers from the headunit using the orignal factory wiring but it seems not


Any suggestions?

 

[Riz]

The wiring must have broken or been messed about with. Check that the wiring is correct behind the head unit. If the wiring isn't there you will need to feed new cable through. If it is, there is probably a split somewhere.

 

[dave c]

I think its the way the amp / headunit is configured. As when the matey installed it it only had to power two front door speakers and a sub.

I then swapped to 6x9's in neat enclosures and now i've added speakers to the rear doors.

Anymore hints / tips / suggestions

Ta

 

[DC5RS]

take a 9V battery and test the wires if the speakers plays a tone.
If you know this method.

 

[JezW]

From your first post I'm guessing that you don't have the sub in the car anymore...so I'm guessing it's like this:

You've got a 4 channel amp, which has 2 bridgeable channels that can create a channel for a sub (sometimes called a 2/3/4 channel amp). Originally it was setup in a 3 channel configuration, so you had front components + sub. You then swapped the sub for two 6x9s, taking it back to the standard 4 channel setup.

Most likely is that the speaker cables are no longer plugged into the headunit (the amp is running from RCAs). This is the recommended route once you start amping speakers. I'm not sure if it's due to overloading your headunit from running both the headunit amp and RCAs in parallel or just the vast difference in sound quality/volume that you would get between most headunit amps and a dedicated amp, but this is the route that most people take - either amp all the speakers or run them all from the headunit.

When you think about it, if you had a dedicated amp running your front speakers and then run the rears off the headunit, you'll barely hear them. Headunit amps are peak 4x50w but generally output about 20w. Compare this to a midrange amp which is outputting maybe 60w to each channel...

If this is your situation, then these are your options:

1. Check online that it's okay to run your headunit amp and a dedicated amp in parallel...plug in your rears and hardly hear them
2. Buy a 2 channel amp for the 6x9s, run the front components and rear speakers from the 4 channel amp.
3. Buy a mono amp and plug your sub back in. Run the front components and rear speakers from the 4 channel amp. Ditch the 6x9s. Enjoy good sound from the front and rear and nice bass from the boot

You can tell I prefer option 3

There may be other options but those are the first to come to mind (put the spare speakers back in the cupboard you found them? lol)

How many sets of RCAs do you have going to your amp at the moment? If it's only one set and it's already using y leads then your options are limited..If there are two sets then you may currently be running your 6x9s from a sub output on your headunit. I'm not sure how much difference that would make, but the good news is that you probably have three RCA outputs on your headunit.

 

[dave c]

Awesome post Jez and 90% of your assumptions are correct - Thanks

I don't want the sub in the car anymore as it was too big and bulky in the boot and I also actually prefer the sound of amp'd 6x9's

I had thought they'd be quiet (er) running off just the HU but figured they might just add a little something to the setup as they are basically positioned right behind your head where i sit.

I'm gonna have another look tonight but i'm thinking the..."put them back inthe cupboard where i found them" option is the most likely

 

[JezW]

Anytime mate.

To be honest I haven't taken into account the position of the rear speakers in a DC5. The front seats are fairly low and rear speakers are fairly high...you may have a point there, but it could still be marginal if they're run off the headunit.

By the way I changed my mind about option 2...what you should do is get a nice 2 channel amp for your front speakers. The speakers there are pretty low down and the front is where you want the quality and volume... Then hook up the rear speakers and 6x9s to your 4 channel amp. All dependent on the number of available RCA outputs from your headunit though.

Depending on what your 4 channel amp is, something like http://www.caraudiodirect.co.uk/alpine-pmx-t320.html running in line with your other amp may be a huge step up. I'm sure there are cheaper alternatives, that was a very quick search and most Alpine products are good.

Another point though, and possibly most important (especially if you don't want to spend any money!) - Do you really hear those 6x9s well from the boot? You could plug the rear speakers into your amp instead of the 6x9s, or possible get some good speakers for the rear (assuming the ones you found are a bit iffy). Sound follows an "inverse square law", so if the 6x9s in the boot are twice as far from your ears as the rear speakers would be, they'll seem 4 times quieter..