GR86 Rear Speakers

[Road_trip]

I've previously fitted the Focal kit to the front and was very happy with the improvement over standard, but that was always going to be a first step upgrade.
An amplifier, rear speakers and / or a sub was the longer term plan. With this car an unobtrusive build that could be put back to standard, not modifying factory wiring or drilling holes, was also important. The front Focal kit fitted that plan well.

Having seen pictures of the tiny standard rear speakers on our 6 speaker cars, they were something I would never choose to have and in my opinion need upgrading before adding an amp.
The high pass filter on the rear channel in the head unit also means I'm probably going to tap the front channels to amplify the rears and get a full range signal, when I get round to it.
Either way, the rear speakers needed an upgrade. Sound deadening was also part of the plan.
Rear, standard, seats and trim removed:

Any upgrade to the rear would involve fitting larger speakers, 4" being my preference as others have done it already.
There was no point fitting high end speakers in the rear, a mid price range would be better, considering the 'custom fit' Focals used in the front.
High sensitivity of 90+ db/w and the ability to handle 50w RMS.
Pioneer TS-A1081F was what I settled on, RRP around £80, but discounted to £48.


Initial impressions on build quality are OK, not amazing, pressed steel baskets, they seem alright.
But hey, they cost less than £50, I'm comparing them to Focal ES and PC speakers with cast aluminium baskets costing 3 to 6 times that!
I'm sure they'll be fine for a budget build in the 86.

Details on fitting to follow...

 

[sim61]

Whilst you are there, are you putting any sound deadening material on the wheel arch and rear wing? On the inside that is!

 

[Road_trip]

Whilst you are there, are you putting any sound deadening material on the wheel arch and rear wing? On the inside that is!

Yes, I didn't want to have to strip it out again.
I used Dodomat materials, 2 packs (1.8m2) Deaden Pro, 2mm thk butyl with black finish, 2 rolls (2.0 m2) of 8mm acoustic liner and a 'speaker enhancer kit' to seal it.
This did the rear arches, front doors, and under the rear seats.

Panels got approx 40% cover of deadening, then the rear wing (inside) was covered in liner.
The rear arch, sill and up the pillar were covered in acoustic felt material, in a U section, that wrapped up on the inner and outer panels.
Trim panels were deadened locally with small patches, then covered in liner.
Unfortunately I didn't take many pictures of the insulation, there's some good threads on here and the net that detail it.
This is one of the door trims, there's liner under the factory insulation too, where it was possible.
The door closes with a proper dead thud now.

 

[sim61]

Looks great!

 

[leosayer]

Seeing that photo of the rear speakers makes me want to rip them out along with with the frames they sit on.

They seem to do nothing for the sound quality or volume either before or after I installed the Focals in the front.

 

[ZN8]

Did you do anything with the speaker bracket? it looks comically flimsy, the speaker is basically hovering.

 

[Conscript]

I'm sure I saw a post on Facebook where someone had made some wooden brackets to allow for larger speakers, but I can't find it now.

 

[Road_trip]

Apparently there are 2 types of standard rear speaker brackets used in the GR86.
2.5" as used in all 6 speaker cars. This is all UK, EU, and base spec US.
3" as used in the 8 speaker Premium set up. The same bracket is used in the old GT86 set up.
I've seen pictures of both types modified for larger speakers, but none looked satisfactory to me, and there is no way 4" will fit in the 2.5" brackets I have.

I've also seen brackets cut from plastic sheet material to house 4" speakers. While they looked better, they also replicated the skinny arms of the factory brackets and used only the 2 original screws to fix them. Not ideal.

The plan was to make new brackets from plastic sheet, with additional fixings and filled in between the arms for strength:

The plastic used was 8mm thick HD-PE material. Conveniently available in a chopping board sized piece at various retail outlets.
It's dead easy to cut with a hole saw, jigsaw and drill holes.

The first test fit revealed they were a bit more flexible than expected. A dig around the garage found some aluminium section to stiffen them, fastened to the back with self tapping screws and notched for clearance. None of the spare connectors in the Focal kit fitted the rear harness plugs, so the originals were cut off the old speakers and soldered to the Pioneer fly leads. A bit of acoustic foam was added to the back for good measure.
The magnets were also very close to the flange of the body pillar, not touching though a few mm clear. So a patch of foam was stuck on the pillar too.

Foam rings were made from the Dodo kit and stuck to the front of the made up bracket.
The factory fitted white deadening material on the trim panels (as on the front door picture above) was carefully cut to enlarge the holes and allow the foam rings to seal directly on the inside of the trim panel.

Brackets, speakers and made up leads, ready to fit.

A final test fit before removing them to fit the sound deadening.
The top is fixed with 2 M6 bolts. The original plastic insert was removed from the screw hole on the body, the other bolt goes through the hook/locator hole. No drilling required. A 8mm spacer was used behind the bracket, cut from the same plastic material. Nyloc nuts and large washers used on the inside.
The bottom fixing uses the original screw, into the insert in the pillar. I would have preferred to use a bolt here too, but there is no access to the back to fit nuts.
The bracket was counterbored to half depth to give the short screw enough engagement. A flat blade wood drill was perfect for counterboring the plastic.

For the final fixing after sound deadening, the connectors were wrapped in foam and zip tied to the pillar at the electrical ground point.
Refit trim panels and rear seats, job done.

 

[Road_trip]

First impressions, Yay! I can hear some good sound from the back. The whole car now seems filled.
What is apparent though is the total lack of bass in the rear, due to the filter in the headunit. As said at the top, I've a plan to do something about that.
The sound deadening has also done wonders, it all seems more solid and tight.

Settings now used,
trebble, -2 to tame the Focals.
mid, 0
bass, +3 to make up for there lack of lows from the rear.
All other effects OFF, fader and balance 0

If it had sounded this good from new I wouldn't have changed anything. Yes, it's not perfect, nothing ever is, and when you start modifying cars where do you stop?
I'll be living with it for a while before deciding what to do next.
The Pioneers are are a good fit in the system, certainly not as shrill as the Focal tweeters can be. If only there was a simple way to give them a full signal.
On their own they aren't the answer to the car's audio problems, fixing the front speakers was the biggest issue.

Total spend so far £320.
Front Speakers £150, Rear Speakers and home made brackets £50, Sound deadening (partial) £120

Tips,
1) Kevin Vo's YouTube video on rear seat delete tells you all you need on rear seat and trim panel removal.
2) While you've got the front door panels off, tighten all the screws on the inside of the trim to reduce rattles.
3) When sound deadening the door panels, pay particular attention to the cup holder area. The cup holder is a separate piece, I put foam in the joint gaps and deadener over the joins where it touched the main panel, to stop vibration.
4) The white factory sound deadener can be welded or stuck to the trim panel with a hot soldering iron, if it becomes detached or torn.

 

[Road_trip]

After a few weeks getting used to the rear speakers, the limitations of the system as it is are showing. That is, 1) the lack of bass from the rear and 2) some music sources don't sound great, compressed, over processed and not natural.
I've tried a few things that some might find of interest.

It's well known and fairly obvious that the signal to the rear has the bass filtered out, but no definitive proof of at what frequency. How much is missing? How much could be added back into the rear speakers?
I played test tones via the aux input, with the equaliser all set to 0, first with the fader set fully to the Front, playing through the Focal IS-TOY-165 speakers.
I was amazed to be able to faintly hear the test tone as low as 40Hz, by 60Hz the level had increased and at 80Hz it was at a good level that seemed constant after that.
So the front channels are getting a full range signal and the Focals are able to play down to 80Hz or a bit lower.

Next try, same tones, same volume and settings but fader set all the way to Rear. Playing through the Pioneer TS-A1081F's.
The sound level started to reduce around 180Hz and is virtually gone at 125Hz, still a very low level around 100Hz.
These values seem to be consistent with a 150Hz High Pass Filter applied to the rear channels. I've seen 150Hz mentioned elsewhere and that appears to be correct.

Based on the above, using the Front signal to amp the rear could gain a useful improvement in the range between 80Hz and 180Hz.
I doubt the 4" Pioneers would do anything below that and suspect 100Hz is about the point they start to tail off.
That increase in range would help round out the system but I'm not expecting anything transformational.

Sources.
I have for years continued listening to CDs in the car for sound quality. I don't stream music or Bluetooth from a phone. DAB and MP3s on a stick have been accepted as a compromise for convenience but in the GR86 a better alternative was needed.
FLAC seems to be a commonly used digital format, also supported in my other vehicle, so I'm slowly converting CDs and putting them on a new stick. After initially selecting too high a sample rate, 768 kB/s works in both cars and gives a very good sound.
It’s not quite CD quality but almost, this format could finally get me out of having discs in the car!

AUX input.
I'd read on GR86.org that the AUX socket bypasses the DSP in the head unit, less processing giving a better result. Even to the extent that Vocal Image Control is bypassed and doesn't work. So I thought I'd give it a try.
First impression was it didn't sound much different. Vocal Image Control still shifted the sound around. The rear High Pass Filter was still active.
I couldn't tell if it bypassed anything at all, worth a quick try but I'm not going to go any further with that one as it would require another new storage format for me.
- Edit- I tried a different source though the AUX today, the socket is EQ'd differently. There's less bass than when playing through the USB, overall I preferred the USB.
That would kind of make sense, if the system has been tuned to make the best of it's own digital sources and internal amplifier.

 

[Vistalite]

An excellent and informative post Sir, thank you.

 

[Conscript]

Bit of a thread bump, appreciate you might not know OP, but seems the best place to ask....is the mounting position for the rear speakers the same as it was in the GT86? It looks very similar. Reason I ask is that there's a a guy selling a set of rear Focals on Facebook with a custom bracket to fit them into a GT. Thought it might be a nice plug and play upgrade.

 

[Road_trip]

Hi, yes, the mounting position is the same as the GT86.
The 'Premium' 3" speakers in the US spec GR use the exact same bracket as the GT86 and they are interchangeable between models.

There might possibly be an issue with clearance of the bracket to the trim panel. That depends on the shape of the custom bracket, and if the trim panel changed.
I do think that's highly unlikely to be an issue, just a remote possibility with custom made parts.

The other thing that might not make them a straight plug and play is the harness plugs.
I believe there are slightly different plugs in the GR for 3" Premium and 2.5" Non-Premium speakers.
I don't know which plug the GT86 uses, but it's easy to cut off the old one and reuse it, if needed. ( as I did above)

Hopefully they will go straight in, if not it will be a minor and easy fix.

 

[Conscript]

Hi, yes, the mounting position is the same as the GT86.
The 'Premium' 3" speakers in the US spec GR use the exact same bracket as the GT86 and they are interchangeable between models.

There might possibly be an issue with clearance of the bracket to the trim panel. That depends on the shape of the custom bracket, and if the trim panel changed.
I do think that's highly unlikely to be an issue, just a remote possibility with custom made parts.

The other thing that might not make them a straight plug and play is the harness plugs.
I believe there are slightly different plugs in the GR for 3" Premium and 2.5" Non-Premium speakers.
I don't know which plug the GT86 uses, but it's easy to cut off the old one and reuse it, if needed. ( as I did above)

Hopefully they will go straight in, if not it will be a minor and easy fix.

The guy in question did state he replaced the connectors to fit the GT, so hopefully they'll plug straight in to the GR. Cheers for that info, I may take a punt on them, then use the Puzu to tune them.

 

[Conscript]

I contacted the guy and unfortunately, it turns out that the tweeter cone of one of the speakers was damaged. He had just been sending more bass to the rear to compensate - but given what you've recently learnt about the build in high pass on the rear channel in the GR, that wouldn't be possible without replicating the work you've done, and frankly, I'm not up for that

Nevermind. Not really sure the rears add much, just thought I'd take the opportunity for an easy plug and play upgrade if it came to it.

 

[Road_trip]

Nevermind. Not really sure the rears add much, just thought I'd take the opportunity for an easy plug and play upgrade if it came to it.

It's a bit of a shame they were damaged, but good he was honest about it.

I've ran the Focal front, Pioneer rears without an amp for 6 months, including a 10day, 2200 mile trip just recently. I got back thinking "it sounds good, I'm not desperate to change anything" The rear speakers lifted the sound, filling the car, and allowed me to turn down the treble to the Focals which are a bit harsh at times. It was a bit time consuming to fit the rears, but well worth it. I'd do it again.

I'm a bit picky, knew the system could sound better, so when the opportunity to add a Puzu Amp came up, I went for it.
Modified the harness, as that was a must with the better rear speakers.
Just driven 400 miles with the Puzu fitted and this time I'm sure it won't be changed again. A bit of fine tuning, but that's all.

 

[Conscript]

Yeah I have the Puzu amp. But if I understand correctly you still need to rewire the rear channel to get around the head unit high pass, is that right? That's the bit I don't really want to tackle.

 

[Road_trip]

Yes, it's really only 4 soldered joints, all in the Puzu adapter harness. So there's no risk to the car harness if you're not confident, or take it out and get someone else to do it.
As said, I wouldn't do this unless the rear speakers have been upgraded, it's not worth it in that case.

 

[Diggler]

It's a bit of a shame they were damaged, but good he was honest about it.

I've ran the Focal front, Pioneer rears without an amp for 6 months, including a 10day, 2200 mile trip just recently. I got back thinking "it sounds good, I'm not desperate to change anything" The rear speakers lifted the sound, filling the car, and allowed me to turn down the treble to the Focals which are a bit harsh at times. It was a bit time consuming to fit the rears, but well worth it. I'd do it again.

I'm a bit picky, knew the system could sound better, so when the opportunity to add a Puzu Amp came up, I went for it.
Modified the harness, as that was a must with the better rear speakers.
Just driven 400 miles with the Puzu fitted and this time I'm sure it won't be changed again. A bit of fine tuning, but that's all.

I've got the Focals in the front along with the Puzu DSP too and am thinking about upgrading the rear speakers. Just out of interest, what 'settings' do you have in the Puzu for the rear speakers you fitted? Apologies - I am not exactly a wiz when it comes to car audio systems (I calibrated my Puzu using some setting a forum member shared on here who had installed the front Focals and the Puzu DSP in his car - I believe he used some sort of calibration mic). Oh I also have an Audison sub in the boot, so I expect it will more than compensate for the lack of bass in the rear speakers? Thanks

 

[Road_trip]

Hi, I'll get some screen grabs of the curves and settings in a day or two. I didn't export it after the last adjustment, probably best to keep a record, just in case it looses it.
The rear curve was relatively flat, in comparison to the front.
For the front I reduced the EQ where the Focal tweeters are very peaky.
The manufacturer's info on the Pioneers showed them to have a more linear response, hence less adjustment was used.

The biggest issue with the output from the factory headunit is the EQ curves vary massively dependent on the volume setting.
I found at times the bass would actually increase as the volume was turned down! I couldn't believe it at first, some tracks are worse than others, but it definitely happens. The best plan is to set up the Puzu for a compromise, ie, sound good at the volumes you listen to most and OK above or below that, without getting too boomy in the bass.

Regarding your Audison sub, yes it will fill in a lot of the missing bass in the rear. How much depends on the crossover frequency setting.
It should be able to play up up to the 150Hz point where the rear signal is cut.