Fitting Rear Speakers?

Chat about your facelift 9n3 Polo - Including the 9N3 Polo GTI!
Post Reply
Posts: 3
Joined: Tue Jun 14, 2022 11:05 am
Drives: 2007 Polo 1.4 16V 9N3 5dr
Location: UK

Fitting Rear Speakers?

Post by polovw1 »

HI there,

I'm thinking to fit some speakers into the rear doors of a '07 Polo 1.4 16V 5dr. It does not have any speakers in the rear but does have cut-outs for the mid-bass speakers. The car originally came with a RCD200MP3 unit but has been replaced with an Alpine CDE-193BT Single DIN stereo. I have also fitted an Alpine 8" Active Subwoofer in the boot. From the other posts I've seen people seem to discourage this idea but I want some balance of sound as people often sit in the back of the car. At the moment, all the treble comes from the front tweeters. In terms of wiring, am I right in assuming there is no prewiring for the rear speakers? Would I have to run new wires to the head unit? Also, I just want speakers to fill the sound so found some cheap Vibe Critical Link Coaxial Speakers (2 for £20). Add the speaker adapter brackets (which I assume I would need) and the total is £30. My only concern is as they have tweeters built-in would a treble inbalance be created as the front tweeters are pretty rubbish and the treble bands on the EQ are near max at the moment? Any suggestions/advice would be appreciated.

Posts: 1
Joined: Fri Jul 22, 2022 1:34 am
Drives: 9n3 2006 1.2 12V
Location: UK

Re: Fitting Rear Speakers?

Post by Sam78 »


I have a 3-door 2006 9n3, and have fitted rear speakers behind the door cards and an active underseat subwoofer. I don't regret it, even though I rarely have any backseat passengers (just as well with a 3 door!). But I know that auto audiophiles don’t tend to go for rear speakers, as you say. I find they help the sound to fill the car better, and you can always adjust a bit the rear fade to dial them down later. The trebles in the rear were not overly fierce from the coaxials in my setup, but i did find i needed to lower the treble EQ all over as my upgrades were more responsive, and also lower the bass (due to the subwoofer), so the EQ is fairly neutral now.

I chose to fit coaxial JBL speakers which have integral crossover, and I chose fairly low power ones (35-40W RMS) as a) I want to retain some of my hearing into my 50s, b) i wanted to keep the headunit and c) the subwoofer handled the lows so well that i don't have to ramp up the volume on the door speakers until it distorts. I matched these new JBL component speakers in the front doors and A-pillar tweeters, with the crossovers mounted within the doors.

To answer your question, yes I needed to route new speaker cables from the headunit (RCD200 in my case) to the rear speakers. Route them behind the dash each side and within the underdoor trim, and then you will need to go in to the door via the door coupling stations. When you wire the speakers ensure you know which is positive and negative - convention tends to have the wire with the white stripe as negative. Also put a bit of tape or other label on the wires to label left rear and right rear. At the head unit you need to buy 4 VAG female terminal contacts of the correct size (2.8mm), crimp or solder them onto your speaker wires and then insert these into your VAG speaker connector (with VAG connectors you usually need to release a pink contact-locking slide clip before removing or inserting contacts). The headunit connector harness holds several (up to 4) individual plugs, so extract the one holding the speaker connections from the harness in order to release the locking clip and insert contacts. Again, ensure you are clear which pin relates to which speaker connection (Rear Left +, Rear Left -, Rear Right +, Rear Right -). But I would always advise taking the headunit out before doing any of this work and inspecting your connector, the pinout ‘map’ and just double checking the male pins are definitely there too.. Then it's just plug in and play. I used VCDS (you need licensed version) to recode the headunit to a 2 front and 2 rear speaker setup but that didn't appear to be essential - it still worked before i did that, whether it made any internal fine tuning such a miniscule rear phase delay I’m not sure.

In my 3 door there were grilles fitted in the door cards but they weren't drilled out, and there was no bracket or anything behind the trim. I manufactured large thick MDF 3-point speaker brackets and mounted the speakers within the plastic adapter mounts, made foam baffles to extend from the speaker to the door card trim, used compressed rubber between all materials and on fixings etc. I also put plenty of soundproofing matting behind the speakers, and took the opportunity to put soundproofing over the entire rear section of the outer skin (not possible on the doors without taking them apart). It is possibly (but i'm not certain) easier to install speakers into the rear doors rather than behind the door cards on a 3-dr 9n3, because presumably on a 5 door you will at least have the circular holes already there in the metal door plate (as in all front doors), so you will just need plastic mounting baffles/adapters to mount onto the metal and bolt these in (test the fitting of speaker clearance with the window lowered, but always do the drilling with the window up out of the way). Professionals use ‘rivnuts’ (which require a specialised tool) but I just used screws into the metal with 5mm thick 1x1cm slices of hard rubber for the screw to bite into on the rear of the mounting plate for additional security (the rubber needs to be sufficiently thin and the screws short enough to avoid interference with the window mechanism). As for coaxials vs components, with a 5 door I think sometimes there are circular cutout guides for tweeters in the upper part of the door behind the fabric part, so you could install components and mount the crossovers within the doors, but you will only know this when you have removed the door trim.

Hope this helps
Post Reply