Problem with Rainbow speakers and D class amp

[darek_u]

I have a problem that I cannot solve... I can't get both front speakers to play... So weird... Here are the details of my setup:

Front Rainbows DLX 4.7, rear Morel Ultra 5.2 Mk. II, amp is D class Focal 4.320. Signal for front speakers goes through factory wires bypassing fader and through HF. HF hijacks front speakers only during incoming call. Rear speakers are wired directly to amp. Amplifier is set up to clone signal from front channel input to all 4 channels output, in other words one pair of L+R signal is amplified and played through 4 speakers. When I connect everything and play music I can hear all but front left speaker. Rears always play fine. Now what I've done so far to troubleshoot:

First thought - something with the wires. I swapped out front L with R wires - music plays in L speaker, not in R. OK, so wires are fine
Second thought - I screwed up input/output settings in amp. I toggled all switches, set it up zillion times - no joy.
Third - well, I got bad amp straight out of the box. I sent it to Focal repair center under warranty. They called after few days and said that the amp is perfectly fine, no matter how hard they try to fail it... Anyway, they resoldered few joints etc. and sent it back to me.

I put it back in place, reconnected all wires and problem is still there...

Next I tried other signal source - Technics CD player. No difference, still L front channel has no sound.
Next I started to fiddle with wires. And here comes first surprise. If I disconnect ANY of the front speakers - both are mute. So if I disconnect L that doesn't play anyway - R stops to play. WTF? To force L to play I have to connect it to R output and L to R, otherwise it won't play. I really can't wrap my head around it...
I followed this path and instead of Rainbows connected OE speakers - they play fine... both channels... WTF?
To make it even more weird if Rainbows are connected directly to Becker radio they play fine, both L and R...
Does it sound familiar to anybody? I really run out of ideas...

 

[Blankets]

I have a 93 and front speakers are wired in series with the door speakers, this results in (off top of my head) a combined impedance load of 6 ohms.

maybe your amp has protection circuitry for uneven impedance load. Do you have a multimeter?

also I believe just one of the factory speakers was a duel voice coil , one for music one for phone.
Another thing you can use a 9 volt battery to test your speaker wire circuit. Just connect positive and negative to speaker wire circuit and you will hear an audible “pop sound”, this can be used to confirm polarity also.

UPDATE: In order to minimize confusion I have 1993 equiped with "Two piece radio with CD player" page 131/7 + page 133 of the ETM manual.
also my front door and front dash spk are wired together in parallel circuit.

 

[gsxr]

If the OE speakers are 6 ohms, the lower impedance of the Rainbows may be causing issues, especially if they are wired in parallel with any other drivers.

Do you have any other speakers wired in the same channel as the Rainbows? (I.e., door speakers?)

 

[darek_u]

Rainbows are 4 ohm, Morel are 4 ohms as well. Rears are wired in directly to ch. 3 & 4, fronts (Rainbows) are using factory wires... I don't remember now but isn't negative wire common for front speakers?
I have only 4 speakers, my car doesn't have active bass.

 

[Blankets]

Page 131/1 of ETM is this your factory radio setup? If so you should have a brown (-) and a black (-) if im reading it correct.

also I forgot to mention had to edit my post. Once you feel the wiring is correct for an individual speaker circuit connect a 9 volt battery
speaker (+) to Bat (+) , speaker (-) to Bat (-), this will create an audible pop sound and if the polarity is correct the cone of the speaker should move out/ forward.

 

[darek_u]

Page 131/1 of ETM is this your factory radio setup? If so you should have a brown (-) and a black (-) if im reading it correct.

I have Euro car with standard speaker setup - in this case BE1460 (2 parts radio) and 2 front, 2 rear speakers. No active bass or sound system. If you have a wiring diagram for this particular system - can you post it please?

 

[Blankets]

http://www.w124-zone.com/downloads/MB%20CD/W124/w124CD1/Program/ETM/ETM.pdf

Is this your radio setup?

Page 131/1?

 

[darek_u]

No, I have 2 piece radio but idea is similar - speakers connected to tuner/amplifier through fader. I think I found a reason... I read 4 ohm between - for L and + for R... It looks like I connected wires other way round I need to dig out the connector I made under the fader and check it out.

 

[darek_u]

Like suspected - wires connected other way round... Shame on me Everything works as designed now.