My unorthodox audio upgrade.

[Magicarcher]

I have just completed a rather unorthodox audio upgrade which I thought I would share with you in case you have any inklings to be as mad as me. It is a fair bit of work though.

The audio upgrade involved: adding a second head unit (Pioneer DEH-X8700DAB) fitted in the rear lockable cubby box between the two seats; fitting a 4x70W power amplifier (Sony XM-N1004) in the rear bulkhead of the boot; fitting a pair of Reckhorn D165 6.5” long throw speaker driver in place of the two rear stowage areas (after a fair bit of modification to the stowage area body panels).

Preparation:

Removed all trim in the boot to access the rear bulkhead; removed the centre rear cubby box and two rear speaker panels; removed the 6 disc CD changer; removed front centre console switchpack and handbrake trim panel, removed the passenger’s side glovebox, glovebox carrier and drop the fusebox to gain access to the connectors on the rear (some pictures shown below)




Head unit installation:

I decided to utilise the CD changer mounting bracket to mount the radio where the CD changer was. The LHS of the bracker (looking rear) had holes that matched well to the side fixing holes in the radio. For the RHS I made an angle bracket out of some 3mm aluminium I had knocking around (the squared edge isn't an issue, nothing is anywhere near it).



The connections to the radio aligned perfectly with the rectangular cutout on the rear bulkhead.



Wiring was straightforward, because I was using an amp I did not need to connect the speaker which left four wires to connect up:

1. B+
2. Aux
3. Ground
4. Amp control

I made a small harness to go to the fusebox and connected as follows:

Connector X11005 Pin 2 in fusebox (spare fuse 3 now 7.5A) to radio B+ using 2.5 sq.mm TWC.
Connector X11007 Pin 3 in fusebox (fuse 47 infotainment 7.5A) to radio Aux using 0.75 sq.mm TWC.
Ground X13004 (RHS rear) to radio ground using BMW ground bus.

I disconnected the two BMW rear speakers and fed these into the aux in connector on the headunit using a high level to low level converter, this allows the existing BMW head unit to play FM through the Pioneer head unit and I don’t have to mess around with a second FM antenna or splitters to listen to FM. I used a stick on DAB antenna on the front screen for DAB.

Speaker Installation:

My plan all along was to use the steel fabricated stowage areas to create a sealed box sub woofer. The challenge was sealing them, these boxes are literally like colanders. Aside from a big rectangular hole in the top of the box, a 35mm diameter hole at the back and a 10mm hole in the side, most seams had big airgaps.





For the speaker to perform well they all needed to be airtight. I made a rectangular plate out of 2mm aluminium for the top hole, and used a electrical box knockout for the 10mm hole in the side. I decided to use the rear hole to take two speaker connectors out. To do this I cut out some 5mm ABS plastic slightly larger than the cutout fitted from the rear. All these were glued with epoxy resin. I then patched over the top of them with glass fibre matting. I filled all the seams with Milliput.





I then liberally covered all flat panels with Silentcoat.

To be continued as it won't let me add any more files.

 

[Magicarcher]

I then liberally covered all flat panels with Silentcoat.



For the speaker plate I was originally going to use 18mm ply, but had some concerns: cutting the 149mm diameter hole for the speaker accurately enough; the speaker would sit very far forward and may interfere with the grille; the speaker screws would be very close to the edge of the 149mm hole and may break through. I decided instead to use 4mm aluminium sheet, this was easy to shape and cut with good accuracy.



I smeared RTV silicone gasket around the edge of the plate and bolted it in place with 6mm bolts.



Once the silicon had set I loosely filled the speaker box with polyester sound wadding, connected up the speakers and then pop riveted them in place with 6.4mm x 15.5mm sealed end pop rivets. I finished off with a section of silentcoat and covered it with closed cell sound deadening foam.




I finished off with a pair of carver grills from my BMW dealer



The Amplifier:

I fitted two 6mm x 60mm long studs onto the rear bulkhead to hold the amp in place and fitted two 6mm rivnuts to secure the top of the amp. I built some spacers out of ply for two reasons: To keep the amp away from the carpet and allow some air to flow behind; It was risky fitting the amp so close to the stereo (it is inches away) as there could easily have been interference. In this case my plan was to sandwich a grounded steel plate between the head unity and the amp. Thankfully this wasn’t required. The amp was powered with two 10 sq.mm power cables and a 60A fuse adjacent to the battery positive terminal (75mm of cable unfused). I made a pair of 2.5 sq.mm twisted pair speaker wires which connect the amp speaker front output to a 3 way crossover under the heater unit for my front speakers.



I connected the front speakers line in to the Head unit front line out and the rear speaker line in to the head unit sub woofer out.

Setting it all up:

Having wired it all up I switched it on and put a test CD in and began tweaking. The rear speakers are 6dB/W less sensitive than the front speakers so I adjusted the input sensitivity to give more power to the rear. With default head unit settings the power was very good, the bass was not bad but needed some work, but the most annoying thing was there was too much directional sound from the rear which upset the soundstage. I went into the settings and noticed that the low pass filter was not set for the sub woofer, so I switched this on. But I still wasn’t happy with the bass, sure it was loud but it was not tight and with the work I had put into sealing the enclosure. I realised the woolly bas was coming from the front focal footwell speakers. Thankfully the headunit had a high pass option for the speakers. After a few experiments I settled on rear subs LP filter 125hz, front speaker HP filter 125hz. Bass now much tighter, just have to get the level of bass to my liking but the head unit allows fine tuning in 1dB steps.



Modes:

Hands Free
Bluetooth Streaming
USB
CD
DAB
FM (not used)
Aux (used for front radio which has FM, CD, Aux of its own)

The cost:

Amplifier: £80
Head Unit: £120
Speakers: £66
Materials estimate: £50
Carver Grills: £81

Why:

The biggest disappointment I had with my Z4 when I picked it up was the audio system. The lack of a mid range speaker in the front doors and the inclusion of a mid range speaker in the rear bulkhead didn’t create the soundstage to my taste. In addition I was keen for more power and bass than the standard head unit (6W RMS/Channel I believe) and more features (DAB, USB, Bluetooth, Handsfree etc.). I improved the soundstage immediately by fitting 3 way Focal 165 AS3 speakers and fading all the sound to the front. To improve the features and power I decided to replace the headunit with an aftermarket one with line out, handsfree, DAB and ability to play FLAC files. This would be combined with an aftermarket 4 channel power amp. My original intention was to fit the AM headunit in place of the existing BMW Business CD using facia adapters, and this was a driver for my choice of Pioneer DEH-X8700DAB, I liked the simple look and thought it would best suit the Z4. However when I installed in the dash with a facia adapter I just didn’t like the look. I tried a different design adapter and still didn’t like the look. So I decided to embark on this modification.

The setup in use:

There is a lot I like about the setup, I like the features and how the headunit functions, the power is more than adequate without noticeable distortion and the bass is nice and solid, to be honest if it were louder it wouldn’t be safe. There are a few things that are mild annoyances:

Traffic Announcements on the headunit appear only to work in FM radio mode, and I am unlikely to ever use that.

Controlling seek, volume etc in a unit behind me is far from ideal. If I had known I was going to fit the headunit here when I bought it I would have chosen an alternative model that could be controlled remotely from my phone. It isn’t a major issue because I mostly stream FLAC files from my phone anyway. In addition I have bought a remote control and intend to fit an IR receiver/transmitter so I can point the remote forward.

Things still to do:

Trim the wiring in the boot (highest priority)
Fit IR receiver/transmitter (medium priority)
Trim the gap at the bottom of the headunit (lowest priority)

 

[mr.tourette]

looks like a right old job.. glad Im happy with my dsp system because I wouldn't want to get stuck into that .. well done sir

 

[Magicarcher]

looks like a right old job.. glad Im happy with my dsp system because I wouldn't want to get stuck into that .. well done sir

Thanks, the job itself wasn't difficult, but it took a lot of time, especially preventing the speaker box construction, it was royally p*****g off my wife. You should be pleased with your Hifi system, I haven't heard one, but the spec is good. Unfortunately mine dodn'y have it.

 

[Wrighty]

Cracking write up

Always wanted to change the radio unit in mine to something with DAB but like yourself much prefer the look of the OEM one.

Really tempted to do as you have but I am quite lacking in the audio/speaker area

 

[Magicarcher]

Really tempted to do as you have but I am quite lacking in the audio/speaker area

You don't need to be an expert in audio/speakers to do this upgrade. The key thing is if you use these speakers (which I believe offer the best performance/cost ratio available), the enclosure they are mounted in must be fully airtight for them to sound optimal. The most important things to do this upgrade are:

• You need to be comfortable removing and replacing trim

• Basic metalworking skills would be a great help for creating brackets and speaker panel

• You need to be comfortable interfacing with the vehicle electrical system as you need to connect supplies and grounds (you don't need to do it the way I did which is more work than most would be bothered with) and you need to be able to hook up either the head unit or the amp to speakers

• You need a fair few tools, e.g: jigsaw, vice, files, drill, trim removal tools, appropriate crimp tools, pliers, cutters

But if all you need is DAB you could just fit an external DAB unit plugged into the aux socket of the business CD.

 

[adam1985]

What is the DAB signal like? I used one of the stick on windscreen types and cant get any signal

 

[Magicarcher]

What is the DAB signal like? I used one of the stick on windscreen types and cant get any signal

I have just ran a test. I picked up 32 DAB radio stations. I checked the signal strength of the 12 I most like (including BBC R1 to R6) and they were all 5 bars out of 5 on the radio display, and sounded fine.

 

[rally-chris]

What is the DAB signal like? I used one of the stick on windscreen types and cant get any signal

I have the same Pioneer head unit as OP, and use a windscreen mounted aerial without any problems, signal is as good as the factory DAB in my Volvo. In fact this is the third BMW car I’ve retro fitted DAB in and used a glass mounted aerial in each case.

If you are having problems with DAB reception in a known to be good DAB reception area, then I’d question if you a) bought a powered (amplified) glass mount aerial, and b) if so, did you connect it up correctly? There is usually a flexible foil ground connection that has to be stuck down to bare metal on the car body, so you have to physically scrape/sand the paint away on the A pillar before fitting. The +12v connection can come either via the aerial signal connector to the radio, in which case antenna power needs to be switched on in the menus of the head unit, or provided by hooking up a separate wire on the aerial lead to a switched 12v feed in the head unit wiring harness.

Chris

 

[adam1985]

I have just ran a test. I picked up 32 DAB radio stations. I checked the signal strength of the 12 I most like (including BBC R1 to R6) and they were all 5 bars out of 5 on the radio display, and sounded fine.

I have the same Pioneer head unit as OP, and use a windscreen mounted aerial without any problems, signal is as good as the factory DAB in my Volvo. In fact this is the third BMW car I’ve retro fitted DAB in and used a glass mounted aerial in each case.

If you are having problems with DAB reception in a known to be good DAB reception area, then I’d question if you a) bought a powered (amplified) glass mount aerial, and b) if so, did you connect it up correctly? There is usually a flexible foil ground connection that has to be stuck down to bare metal on the car body, so you have to physically scrape/sand the paint away on the A pillar before fitting. The +12v connection can come either via the aerial signal connector to the radio, in which case antenna power needs to be switched on in the menus of the head unit, or provided by hooking up a separate wire on the aerial lead to a switched 12v feed in the head unit wiring harness.

Chris

Thanks for the replies I have the Pioneer DEH-X7800DAB and the seller i got it from included a DAB aerial. I assume that it is powered. I still have the instructions in the garage so will take a look. it has been installed for nearly a year and the DAB never worked. Ill also check that powered aerial is turned on in the HU. I need to take the HU out anyway as my steering wheel controls have stopped working, think there might be a loose connection.

 

[RROB]

Great info....

for a more basic front end fit does anyone know if the existing CD changer can work with this unit ?
Also I've seen aerial connections that allow use of the standard stubby or whippy ? for FM or DAB

has anyone fitted one if they work ?

 

[rally-chris]

Great info....

for a more basic front end fit does anyone know if the existing CD changer can work with this unit ?
Also I've seen aerial connections that allow use of the standard stubby or whippy ? for FM or DAB

has anyone fitted one if they work ?

If you get a modern head unit with USB interface you won’t be worrying about a cd changer. I believe an existing FM aerial will not work well with DAB, because the zed (like most cars) already has an in built amplifier device hat base of aerial) that only passes through FM radio frequencies regardless of what you plug between it and the head unit.

Chris

 

[adam1985]

yea i get FM fine through the oem aerial just need exra one for dab

 

[RROB]

I should have said the connections / loom adapters I've seen use the standard aerial for EITHER when selected...
not one or other.... so its one aerial for all use..

 

[Magicarcher]

Thanks for the replies I have the Pioneer DEH-X7800DAB and the seller i got it from included a DAB aerial. I assume that it is powered. I still have the instructions in the garage so will take a look. it has been installed for nearly a year and the DAB never worked. Ill also check that powered aerial is turned on in the HU. I need to take the HU out anyway as my steering wheel controls have stopped working, think there might be a loose connection.

When I first setup the DEH-X7800DAB the DAB radio didn't work for me. I assumed that my onscreen antenna since it looked like a pioneer one was amplified so I set the "DAB Antenna Power" to on. I subsequently asked some questions on Amazon and got feedback that the antenna was not amplified, so I went through setup procedure again and changed the "DAB Antenna Power" setting to off. It then worked. Here is the one I bought: https://www.amazon.co.uk/gp/product/B01DZW2Y3U/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

 

[RROB]

https://www.ebay.co.uk/itm/DAB-AM-FM-Radio-SMB-Aerial-Antenna-Splitter-for-Pioneer-Car-Stereo-CT27AA136/201926151370?epid=23017009830&hash=item2f03bc8cca:g:TB0AAOSww9xZG1Hk


it wont work with amplified aerials (which I think standard one on car is) ??

 

[adam1985]

I have just ran a test. I picked up 32 DAB radio stations. I checked the signal strength of the 12 I most like (including BBC R1 to R6) and they were all 5 bars out of 5 on the radio display, and sounded fine.

I have the same Pioneer head unit as OP, and use a windscreen mounted aerial without any problems, signal is as good as the factory DAB in my Volvo. In fact this is the third BMW car I’ve retro fitted DAB in and used a glass mounted aerial in each case.

If you are having problems with DAB reception in a known to be good DAB reception area, then I’d question if you a) bought a powered (amplified) glass mount aerial, and b) if so, did you connect it up correctly? There is usually a flexible foil ground connection that has to be stuck down to bare metal on the car body, so you have to physically scrape/sand the paint away on the A pillar before fitting. The +12v connection can come either via the aerial signal connector to the radio, in which case antenna power needs to be switched on in the menus of the head unit, or provided by hooking up a separate wire on the aerial lead to a switched 12v feed in the head unit wiring harness.

Chris

Thanks for the replies I have the Pioneer DEH-X7800DAB and the seller i got it from included a DAB aerial. I assume that it is powered. I still have the instructions in the garage so will take a look. it has been installed for nearly a year and the DAB never worked. Ill also check that powered aerial is turned on in the HU. I need to take the HU out anyway as my steering wheel controls have stopped working, think there might be a loose connection.

Just in case anyone else is having issues with this i just updated the Pioneer firmware to the latest version and now my DAB works