How To Fit An Amp In A V36 Coupe

[The Max]

It's covered by all the standard items in there - plastic well to form the flooring and then the stock boot carpet over the top. No need for any fans and whatnot. The ventilation behind the left guard in that photo is more than enough. The Rockford Fosgate had a much larger heatsink so it dissipated a lot more heat than the Arc XDi v2 does and the floor never got more than just a little warm without deforming the plastic at all.

The reality is though, I'd expect that much because this amp is only pushing frequencies above 150Hz so it's effectively using less power anyway and that translates to less heat dissipation compared to running full range. The sub amp (my trusty old Sony XM-1002HX bridged) is what gets considerably hot and that's the one which is bolted to the sub enclosure, which I'll show in photos of the finished product later. Keeping in mind though, the Sony amp is a class A and they invariably run much hotter than class D anyway.

Nevertheless, heat was the main reason why I didn't want to go for the 6-channel XDi v2 amp. It would've been nice to throw all my eggs in the one basket and it would just fit as it is the same dimensions as the old Rockford Fosgate but the heat would definitely warp the plastic well not to mention the amp would fry the output stage for sure.

[colin.ssc]

Yea thought as much. I went with a 4chn and mono block and mounted them on a board then onto the rear seats (I have a sedan). In hindsight I could have installed them under the well but at that time heat was my concern.

[The Max]

My initial thought would have been to mount behind the seats off the car's metal framework, like I did with my old Maxima. However, being a coupe, that makes it considerably difficult to do neatly and besides which, I just don't fancy the idea of screwing things into the wood backing of the seat. The fact all the sedans and coupes have those M6 studs in the boot floor for the optional factory Bose systems made it all possible and way easier. I'm much more comfortable knowing I didn't have to take a drill to any of the bodywork, though I did need to whip out the Dremel on the plastic well for the cut out to mount the industrial connector and the step-drill for the Neutrik USB panel socket.

I'd still keep the mono block above ground, as it were, given it will definitely produce way more heat than your four channel. Put the two close together in a stack like I made would be asking for trouble without a cooling fan to force some more circulation in there.

[The Max]

...and I just realised looking at the photo that I stuffed up the polarity on the right rear channel, which I thought sounded out of phase to me at the time. Those wires should be in the order of white then grey (9 and 8), not grey then white!!! Fark! Now I have to pop the plastics off one more time. DAMN IT!

Yes, I know I can invert it in the DSP but bad wiring is still bad wiring.

[The Max]

Back again and we can finally put the project to bed. I'm really loving how much cleaner this amp is. I'm never touching another Rockford Fosgate amp ever again and I will certainly recommend against them for those with a discerning ear!

So, after correcting my one wiring mistake with the rear right speaker polarity, the boot floor was reassembled and this is how it looks without the carpet. As you can see, the spare tyre has not been sacrificed and nor should it ever be. While I can understand why audio aficionados are happy to sacrifice their spare tyre, I love my music, I'm extremely passionate about music but there's no friggin' way I'll pay for a tow truck to get me home if I get a flat tyre out on a highway!

And then with the carpet laid over with the hole cut out to accommodate the industrial and USB connectors.

A close up of the connectors.

And then with the subwoofer in place and connected.

It's neat and it sounds great to my ears without compromising the vehicle.

And that's just one way how you can upgrade your audio system! The end.

[The Max]

UPGRADE UPDATE:
So after a while of battling with bok choi mirrorlink devices with mobile phones that would overheat, get a crap GPS signal and often process way too slowly, I decided it was time to put in a much more powerful solution.

Problem: Sick of the lack of Australian GPS to take advantage of! Also weary of the Sony NW-ZX1 walkman solution as my audio player. Need something more easily accessible while on the road.

Requirements: GPS system that can calculate faster than ARM-based units out there, audio system that can provide a nice clear sound (must be compatible with FLAC codec) and somehow integrate with the GPS so that audible directions can be heard alongside the music, preferably dimming the music volume during those instructions.

Additional (bonus) requirements: Interface with vehicle's built-in touchscreen panel.

The system design itself ended up being quite straightforward. At the heart of the system is a Gigabyte Brix i7-6500 NUC, fitted with a 1TB Samsung 970 Pro SSD for plenty of audio storage and 8GB RAM. It was chosen primarily for its size and USB-C port on the front panel, allowing me to move my USB ports externally to the side in what is already a cramped space using a USB hub.

The computer was modified with a small controller board I designed to:

• Wait for the vehicle to be on for ten seconds before switching power to the PC for automatic power-up. This safeguard was put in place for those moments where you might put the car in Accessories/ON momentarily before switching off again.
• Upon switching the car off, emulate a press of the computer's power button to initiate an elegant shutdown of the PC and then cut the power after 30 seconds. Windows is presently shutting down after approximately eight seconds upon initiating the shutdown sequence.

The power supply for the computer needed to provide 19V @ 4A, of which I decided to buy one off eBay as they are readily available for such applications.

The computer peripherals are:

• Digital Forecast Bridge X for HDMI to composite video conversion
• Garmin GPS-18x 5Hz receiver
• USB to Serial adapter for the GPS (modified to supply the required 5V from the USB port directly to the receiver)
• JDS Labs EL DAC II - USB to analogue audio converter, running modified firmware to power up automatically and physically modified to accept an external dual-rail power supply (factory design requires a  minimum 16VAC power supply)
• Adafruit AR1100 resistive touchscreen controller interface, which incorporates the now obsolete but still well supported Microchip AR1100 controller IC that I was planning to design with until I found that someone already went to the trouble of creating a complete PCB with the necessary edge connector and USB connector!

Lastly to power the video converter and the audio DAC, I designed two power supply boards, one providing 12VDC @ 1.2A and the other providing +/-15VDC @ 1.25A. At the heart of both power supplies are XP Power's monolithic block DC-DC converters, which are capable of rock solid and clean power at voltages as low as around 10VDC, not that I would ever drive my battery that low in any situation.

On the software side of things, I am currently using Foobar2000 for my audio, with a skin that was designed around touchscreen use. It looked good on the desktop but how it would look on a 7" screen being pushed through crappy composite video remained to be seen. For GPS, Mapfactor are the only guys who have something decent on the market, based on open source maps (their TomTom offerings are limited to Europe, North America and Africa at the moment) and it's free!! I'd happily pay for their commercial version but it is strictly paid through the maps purchased and there is no Australian map to buy.

The one downside to Mapfactor's software is that it's a choice between Windows and Android. There is no Linux option and I was not prepared to run it in a VM environment. The key here is to have a computer running everything natively to facilitate fast boot and shutdown times.

I'll keep the updates coming as I find time to progress with the project, as it's something I started a long time ago but hardly have had the time until these Christmas holidays to keep any kind of momentum going.

I'll put in the first progress report into the next post of this thread.

[The Max]

At this point, I have got it all installed but the wiring needs a little neatening up, once I get some appropriate length USB cables.

Two issues I came upon with the install were that the USB lead from the audio DAC was about 10cm too short to plug into the NUC's USB port without straining the socket. I can't use the DAC with the USB hub that I've got for the touchscreen and GPS antenna because the hub introduces minor glitches in the audio, no doubt due to a slightly unstable clock that doesn't noticeably affect HID interfaces.

The other issue is that my backup plan of having a Logitech wireless mouse to control the system doesn't work with the PC's built-in bluetooth nor the Logitech RF micro-receiver because it's too deep in the corner surrounded by grounded metal, acting as a large RF shield and diminishing the performance to the back seat. So for that, I need a 1m USB extension lead to bring the Logitech micro-receiver closer to behind the backseat.

The results are not stellar but they're certainly usable, though they have their own minor issues that I need to work through.

Part of the challenge is working out the right colour scheme to give the best contrast in all conditions. The GPS one above has been changed to a perpetual night mode, which pops out of the screen better. The Foobar2000 player below still needs serious tweaking to make it even half reasonably user friendly. One challenge with that is to have it fire up back where it last left off when the car is powered down, and maintain the playlist, like any other car audio product would. The other challenge is to have the controls laid out to be a little more friendly to fingers rather than a more accurate wireless mouse.

Additionally, the one major challenge with this configuration is the fact that the PC's output resolution seems to be ideal at 800x600 with text zoomed in to 125% (medium zoom). If I could be bothered going as far as hacking away at a bok choi device that has a Sony serialiser IC in it (they can't be purchased off the shelf as there are licensing fees involved), then it would be considerably sharper but I'm cheating here by using the composite video input instead.

Another minor challenge I have come across is figuring out how to get the GPS software to dim the music volume to hear the instructions, as right now, they're just mixing together to the point that the navigation software is only somewhat noticeable through the music (not really over the music, as such).

Otherwise, it all powers up and down smoothly. One thing I have found is that if I've got it just on Accessories, mucking about with it and then I fire up the car, there's not enough juice during the cranking to keep the power supply for the PC happy, so it is clearly suffering from that process. If it proves to be painful enough, I may end up designing my own power supply for it after all with a better buck-boost converter for lower voltage tolerances.

Once I have managed to fine tune the software itself, then I can begin with adding automatic synchronisation processes so that while the car is warming up in the garage, it can perform a check for any new audio files I've introduced to my central networked storage server and automatically copy them to the internal SSD.

Audio-wise, I have to say, I'm really glad I chose the EL DAC over other smaller USB-powered makes. The audio quality is stunning in either a home or car environment. I was listening to the track in the photo above and heard some noise in the opening bars, thinking I had cracked tweeters but then realised after listening to the same tune with my audio workstation in the house that the recording itself actually had a bit of buzz from the piano wires!

My only regret, if any at all, is that I bought the EL DAC I instead of the EL DAC II, as I'm noticing a slight pop upon power up of the NUC after 10 seconds. If I had the EL DAC II, it has relays to cut the audio until the USB connectivity with the PC is complete and ready to go. Still, with the way it has been designed and installed, I could always fork out the R&D cash and buy the EL DAC II if I'm pissed off enough with it.

[The Max]

Installation-wise, it's not finished yet, so there is a bit of a mess to clean up.

Tucked away between the left rear quarter and the interior paneling is the JDS Labs EL DAC, held on with a bracket I bent into shape to encompass the DAC and then bolt to an existing hole in the paneling, thereby sticking to my rule of no drilling in this car whatsoever.

The DAC is then padded with 12mm medium density adhesive-backed foam, front and rear. Because there is no hole below for a second point to anchor this device firmly, the bottom swings out toward the exterior panel. This is why I have padded it both front and rear, so that there are no undesirable knocks and bumps on other side to ensure a rattle-free experience as well as protecting the rear quarter panel.

Next up are the power supplies I built. I haven't yet done a trial fit with the plastic flooring to make sure this tight fit will definitely make it or not but I'm slightly optimistic about it. To make sure I could condense the size as small as possible, the enclosure had to be custom made - I bought the perspex from a mob in Melbourne who also cut it up into the required pieces for me. It also has the same adhesive-backed foam stuck to the bottom of it for eliminating rattles and to also raise it off the amp plate to keep the amp's ventilation holes on the side unobstructed. The power supply unit has an 8-way socket/plug arrangement for easy removal, taking in battery, ground, remote on signal that powers up the amp as well, and then outputting the 12V, +/-15V and ground rails for the video converter and audio DAC.

USB cable follows the speaker cabling though it needs to come out now due to the short length.

The composite video converter sits on top of what is the Panasonic navigation and Bluetooth unit in this vehicle. I fashioned a little bracket which utilises the screw holes of that Panasonic unit itself. Underneath that, you can see the 19V power supply for the NUC, which is bolted with a single bracket I fabricated to hover it off the wheel arch so that there would be no vibrations, since there was only the one anchor point for it.

This corner is quite busy, as you can tell. The NUC sits between two sets of speaker crossovers, bolted to a factory M6 stud on the boot floor with a bracket fashioned with an offset to bring it in as close to the Morel crossovers on the right so that there is still enough room for the scissor jack to sit in without hitting it. You can see the additional power and control cabling poking through a hole I cut out of the NUC to interface with the power delay control board that lives inside. That USB cable you see tied to the bracket in the bottom corner is the one from the DAC which was plugged into the USB hub at the time but has to move to the NUC itself for glitch-free audio.

A bit difficult to grab a good wide shot but this is an idea of how it all sits together. Ignore the cable in front of the bonnet pop-up controller, as that's the USB extension lead temporarily bringing that Logitech mouse micro-receiver closer to the back seat so that I can use the mouse from the driver's seat. Pretty much all the wiring closest to the back seat needs shortening and neatening up overall, particularly the extra-long eight-wire controller cable in the left corner which is from the Arc Audio PS8's remote control unit.

 

[KiwiRS4T]

Way beyond my capabilities. Have you got a dollar figure for the components? No doubt would be megabucks if one were to pay someone to do this!

[The Max]

Very good question and something I never really sat down to add it up. Now you're going to make me slap myself.

Components:

• Gigabyte GB-BSi7HAL-6500 Brix Mini PC                           $560
• Kingston KVR21S15S8/8 8GB DDR4 2133MHz RAM       $132
• Samsung MZ-V7P512BW SSD M.2: 1TB 970 PRO            $432
• Digital Forecast Bridge X MC video multiconverter          $800
• JDS Labs EL DAC I (B-stock/factory seconds)                  US$200
• Adafruit AR1100 touchscreen interface                              $10
• eBay DC-DC converter for Gigabyte PC                               $35

Custom built hardware:

• Power Supplies:
  • XP Power DC-DC modules     $150
  • Passive components              $60
  • PCB fabrication                       $40
  • Housing (and perspex glue)  $30
  • Connectors (8-pin locking, 4-pin locking for DAC, 2.1mm DC for video converter) $40
  • Total cost: $320
• PC delayed power controller
  • Circuit                                                           $20
  • Automotive 5-pin mating connectors     $30
  • Total cost: $50

Miscellaneous:

• Cable and connectors (estimate) $100

Total cost comes to $2,439 + US$200. So yeah, I guess if labour were to be charged for this (R&D, installation, software tweaking, etc), this would end up costing closer to $5,000 total. I'm glad I don't offer this solution commercially though, as there will be a lot of imperfections that would take a lot of time to tweak and even then, it won't be totally ideal for every user. Those shitty Tesla-style touchscreens are a classic example of that.

For example, if I wanted to play a podcast off my phone over Bluetooth but still use my GPS at the same time, I wouldn't be able to because I'm using the Aux source for the video input whereas my audio source is Bluetooth, so that means another interface to add in for switching out the audio.

Another example, this solution cannot be driven from the steering wheel. We're limited to whatever we have when using any Aux source. The key here was to retain Bluetooth phone connectivity for handsfree (media being a bonus) and at least maintain volume control on the steering wheel (and centre console). I'm sure some folks out there would've loved OEM integration with the steering wheel controls and honestly, I can't be bothered designing a circuit to interface with the PC via USB nor writing the software for keyboard emulation, which is all I would really need for controlling Foobar2000.

Also, given the very limited choice of good GPS software out there - as far as I have seen at least - it won't be everyone's cup of tea.

I have my day job and it pays me well. I'm just happy to impart a whatever knowledge I can instead. If anyone can take that as a baseline and improve on it with their greater capabilities, that would be a very cool community effort.

[Chris Rogers]

screen on that is GVIF if you want to fiddle with digital only formats. sony CXB1458 is the driver for it.
(I'm still playing with interfacing just not this anymore.)

[The Max]

19 hours ago, Chris Rogers said:

screen on that is GVIF if you want to fiddle with digital only formats. sony CXB1458 is the driver for it.

I've got another idea for that, which will be explored when I have a bit more time on my hands in future. Where you see that BridgeX video converter, as you already know yourself, the unit underneath it is the unit which manages the Nissan GPS side of things. I'm thinking since the GPS video feed from that is superfluous, I suspect it will have the CXB1457R transmitter IC and in which case, I could probably intercept the RGB input to that serialiser IC. In doing so, I should then be able to switch to the car's GPS video input. The other benefit would be that I can do away with the BridgeX unit altogether and just have an HDMI to VGA cable instead.

That way, we should be able to achieve full-time GPS video while still having the Bluetooth audio available to us for streaming the occasional podcast from the phone. Of course, the screen would be a lot sharper because of this too.

However, the problem with this is that VGA is analogue whereas the CXB14xx family expects parallel data, as noted in their datasheet with the 8-bit parallel inputs for each of the three colours in the RGB group. So I would need to digitise it first into 24 data lines before pumping into this little IC. Or, I could go one better and just take the HDMI out directly to feed into a Texas Instruments TFP401 converter and then into the CXB14xx.

This is why I've cheated with the composite video input for now, purely because it has taken me over a year in scrounging for whatever spare time I've had to even get this far. Love my car, love my job but sometimes I just hate my life!!

Many thanks for chiming in though dude. It's always a pleasure to hear from you mate.

Edited December 29, 2019 by The Max

[Chris Rogers]

On 12/29/2019 at 10:50 AM, The Max said:

However, the problem with this is that VGA is analogue whereas the CXB14xx family expects parallel data, as noted in their datasheet with the 8-bit parallel inputs for each of the three colours in the RGB group. So I would need to digitise it first into 24 data lines before pumping into this little IC. Or, I could go one better and just take the HDMI out directly to feed into a Texas Instruments TFP401 converter and then into the CXB14xx.

or look at the intersil (techwell) gear. seen a lot of that used to dump video of all sorts into these screens too. not too familiar with the TI gear.

[The Max]

Unexpected update:
Need to upgrade power cabling for the replacement subwoofer after a small incident last week while driving home.

[The Max]

Howdy all. Time two (hopefully final) updates!

First one is the subwoofer story. I replaced the subwoofer with a Focal K2-E30KX 12", using the same enclosure for now but ideally will need to be a bit bigger for better low-end extension on this critter. Only problem with today's subs is that they're not as sensitive as the old Soundstream was, so it meant having to replace my trusty old Sony XM-1002HX amp with a much more powerful Helix C-One.

Now my back hates me even more when I have to lift this monster in and out, given the amp is a couple kilos heavier than my old Sony (understandably) and the Focal sub is about 5kg heavier than my old Soundstream. Anyway, upgraded the power cabling from 8GA to 4GA (the main feed entering the boot before the distribution block is 2GA) to accommodate the hungrier amp. Only problem I created for myself is that the RCA sockets on these amps are seriously tight tolerance, so the amp doesn't quite like my right angled RCA adapter in that it does fit but then when I attempted to rotate it a little for positioning, I heard a snap and realised I snapped the centre conductor and the outer ground ring off their respective pin and strap. There goes my warranty, since I've had to recrimp and solder a small wire to the board to restore a solid connection. ?

Despite being quite happy with the sound I got from my Soundstream for the last 22 years, I have to say, the Focal has made me realise what advancements I've missed out on over that period of time. So in a way, I'm actually glad my Soundstream died. I just wish it died in a safer manner!! Mind you, this is with the sub not being in an ideal enclosure nor being that well tuned just yet. This will be the final piece in putting an end to this project (or will it?).

A massive thanks to Marty at FHRX Studios for not only his excellent business acumen but also his clear understanding of what I wanted and his subsequent guidance. I had another more expensive Morel subwoofer in mind after hearing it in action but Marty saved me a bundle in steering me towards the Focal without compromising on what my ears like.

Up next, touchscreen control.

[The Max]

So, I finally got around to finishing the touchscreen. Full disclosure though, I'm not entirely happy with it and I knew this restriction going into this project from the beginning.

There are two types of touchscreens - resistive and capacitive. Your phone's screen is capacitive. The V36's touchscreen is resistive.

The downside of resistive is that it does not have the same sensitivity nor resolution that a capacitive touchscreen can offer, so that renders it useless for gestures, such as swiping. Look at the menus of our vehicles and you will see that they don't have any menus built for scrolling, aside from the phonebook and even then, you need to use the jog dial or up/down buttons to navigate those anyway. I have tried for a little while to find a suitable 7" capacitive touchscreen overlay that could be used instead but came up empty-handed.

As a result, we can only do an x,y positioning and left click to be even mildly useful. For the GPS software, that works extremely well as they have designed their own software that way. For the Foobar2000 audio player, I will need to design some scrollbars into the skin so that I can tap my way up or down. Ultimately, that is what's left after completing the hardware installation for this system - software tweaks.

I won't bore everyone with the details about the software itself, though I'm happy to answer any questions you may have for me about this. But to list the building blocks required for this modification:

• Touchscreen HID interface circuit using the now discontinued Microchip AR1100 chip (there may be other suitable replacements today but I haven't looked any further for the reasons above)
• UPDD (Universal Pointer Device Driver) software to translate the AR1100 serial data to human interface device data
  • The latest is v6 but that does not work very reliably in a Windows 7 environment, so be sure to use the latest v5 driver for Windows 7 PCs
• 5m USB lead to reach from the screen to the rear right corner of the boot
• 20cm 4-wire FPC extension cable and suitable homemade female-female joiner (I have yet to find one from a manufacturer)

Let's start with the touchscreen disconnection here. I won't go into the removal process of the screen assembly. It's pretty straightforward. Note down the bottom left corner, where the touchscreen cable is. Carefully disconnect this guy from the display's PCB. You need to pull the latch away from the connector to unlock and then gently pull the thin film cable out. This connector will no longer be used, not that I ever used it apart from the telephone dialler on the odd occasion. That can be done with the physical button panel anyway.

 

Before replacing the rear housing, it is necessary to bend the housing slightly where the cable passes. Normally this would sit on the inside but now we need to bend it in to allow the cable to gently sit outside. It's only a very slight bend, so don't go crazy and brutalise it.

 

Once you have carefully replaced the rear housing, use a small but strong piece of double-sided automotive tape to hold the FPC female-female joiner in place so that there is no stress imposed upon the touchscreen's cable. They are reasonably flexible enough to take a little punishment but the more you can do to avoid them cracking or fracturing, the better. Likewise, tape down the interface board in the position shown. This will allow sufficient room for the USB cable to enter from the hole on the right and plug in without imposing any stress along the materials. Ideally, the hole should have some kind of rubber lining around it to avoid grazing the extension cable. By the same token, this is the added benefit of using the extension cable - it can be a sacrificial and easily replaced component if something were to happen, as opposed to replacing the entire touch overlay.

 

Here is the rear view of our screen assembly. The cable has been stuck down with the same double-sided tape to make its reasonably stress-free journey to the other device.

 

Here is the screen assembly mounted in place and everything plugged in. Note how the USB cable has a gentle bend radius on the cable, which was the aim of the game as previously mentioned.

 

With the vents and button panel assembly reinstalled, you can see that we have just enough clearance in there so as not to unduly stress any of our components. Lucky eh?

 

And that's basically it! Start up your PC, calibrate the touchscreen positioning with the UPDD software (remember, v5 for Windows 7 and v6 for Windows 10), set up the tap gesture for x,y and left-click and there you go.

Until I sort out the scrollbars in Foobar2000, I will need to rely on my wireless mouse for scroll capability but at least I can skip tracks of whatever album is currently playing.