911 SC Audio Recommission and Upgrade Project

[Coastr]

When I bought my car the audio equipment was supplied in a box.  The head unit was sitting in the dashboard, the clock worked but it didn't make any noise.  PO gave the tired old excuse 'all I need is the engine noise'.   While we all like to turn off the audio, wind the window down and hear the exhaust - for me listening to music while cruising down the highway is right up there with having nice AC (also in a separate box).

The good thing about the boxed equipment is that it is all period-correct 1980's blaupunkt.  I don't think it was the original unit supplied in the car - but who knows - could have been a dealer upgrade, or the first owner might have waltzed down to a local audio shop and ordered some blaupunkt goodies (did you know, blaupunkt just means 'blue dot'?)

The head unit is a Blaupunkt CR-30001H :

Which also came with a graphic equalizer (so '80s):

and a 4-channel amplifier "BPA430"

I had no idea if all this worked so I bought a 12v hobby power supply, removed the front speakers from the doors and bench tested it.  It took a bit of fiddling to figure out how to wire it all as I had no wiring diagrams and information on the web is pretty scarce.   A power plug for the amplifier was missing but I figured out it uses a + and - and crimp spade connectors worked OK.  The amp/equalizer/head unit don't use RCAs but instead use a single multi-pin DIN connector.  The head unit has the typical permanent power for the clock, switched power, ground (direct to the chassis) and power antenna trigger.

Here's it all hooked up on the bench working away:

The knobs on these are about triple function so I had to find a manual online and decipher how they worked.  Doesn't help that the backs are a bit chewed out and don't engage with the spindles very well.  However, finding new knobs is a project I haven't set out on yet.

Speaking of the speakers, the original door speakers are still in servicable condition and weren't damaged or crackly, so they have stayed in the car:

The cones are in great shape:

After the successful bench test, all that was needed was to re-install in the car

Putting the front speakers back in I could ID the wire color - based on the sheathing and look of the connectors I would say this is either original Porsche wiring or a very good aftermarket install.  This might be clarified by knowledgeable folks.

I managed to unearth all the speaker wires for front and rear and determine which was which : 

The brown/red wires are the speaker wires.  I routed them through the grommet into the front because I figured the amp had to go in there.  Initially I found some holes drilled on the passenger floorboard and thought that might be the install location, but there's no way this big amp was fitting there.

I test wired everything together in the front just to make sure it was all working on the car power and I had all the wires correct.  I ran a new power wire with inline fuse to the battery terminal for the amp.

It was all working and I found 4 matching screw holes in the factory wooden/cardboard ventilation cover thing.  So I bolted the amp up to that, re-installed the head unit and did a (dodgy) temp install of the equalizer off the bottom of the ashtray.  Tidied up the wiring a bit, and it was all working great.

I cover this all up with the carpet so you can't see it when you open up the bonnet.  You can see the power/earth coming in on the brake booster side and the f/r speakers going out the other side. 

[Coastr]

The next fix was for the rear parcel shelf speakers, which were toasty as I found out when I hooked it all up.  I could easily fix that by fading forwards to the fronts.  

Not good

Here's the details on those original crispy speakers:

I found some good replacements which were a pioneer 4x6 https://www.amazon.com/gp/product/B07GZRCYXN

These dropped straight in without a hitch, and the original covers clipped straight on.

The only issue was the chrome bling on the tweeter, which I didn't like peeking through the factory covers.  So a sharpie took care of that.

All re-assembled and looks factory. 

These sounded much better though the 4x6 format sitting on top of the firewall doesn't give a lot of fill - they are pretty tinny sounding and good for fill/high frequencies only.  

This was the end of phase 1 - recommissioning - which was actually complete in March 2019.  Nothing else happened for the next two years as life events took control.  This setup coupled with a cigarette-lighter Bluetoth/FM adapter worked great for the times that I drove it.  The previous owner thought I was some sort of genius for getting it going again when I showed him, but car stereos are literally chapter 1 in the car mods and maintenance book for a teenager.  However I like to think this is my neatest work ever - some of those teenage years early mods were cringe-inducing in hindsight.

[Coastr]

When I finally got back to it the next phase it was to install a subwoofer.  After a lot of research I went with a powered slimline sub that (hopefully) fit under the drivers seat.  Passenger seat in an SC has the little brain box for the emissions control.

Here's the product : https://www.amazon.com/gp/product/B073W5ZMWN

I mounted it by screwing the edge of a piece of aluminium into the carpet tab, then mounting the front feet to that and putting velcro feet on the back.  There's really no much need to stop it moving vertically as the seat clearance is very small.  It does limit rear seat passenger foot room - not that there is really any people who can get their feet under there.

As this is a powered subwoofer I ran the thick gauge amp wire through to the battery down the LHS of the car, and then ran the triggering wire up to the head unit.  This unit can either take a line-in or speaker inputs.  I first hooked it up to the rear speaker inputs but getting more power out of the sub meant driving the rears harder, which started to distort.  So I switched the inputs to the front speakers.  The sub has a small under-dash knob for sub level as well as a gain control on the unit itself.  With a bit of fiddling I got this about right.  It's not a doof-doof unit but fills out the lower frequencies nicely where the small rears and comparatively small fronts just didn't do much.  Overall it allows you a lot more sound with less volume if that makes sense.  Being mounted directly under the drivers seat you definitely feel a bit of punch with the right music.  It's not visible at all unless you stick your head on the floor and look back under the seat.

The only issue I have is that it does a turn-on 'thump' noise as the power comes through which is probably triggered from the head unit itself (newer head units don't pop and thump the speakers on power-up).  

[Coastr]

Next phase after the sub was actually getting a stealth bluetooth install.  The cigarette lighter FM/Bluetooth units work pretty well - but they're ugly and can fall out with, er, spirited cornering.  I bought a unit which does the same thing (put the audio out into the FM channel) but works by clipping directly into the antenna line.  This means the reception is perfect, and it's hard wired into the ignition.  With the radio tuned to a specific station the phone connects straight away.  

The only visible part is this call button - you use it to answer a phone call, or when playing music it acts as a song skip button.  There's also a microphone that I hooked over the sunvisor which works for hands free calls.  Friends tell me it works fine.  The music playing is great.

Here's the unit I installed https://www.amazon.com/gp/product/B00FRU5UNA

Final addition so far is a rennline magnetic phone mount.  This works great as well, although it's not perfect and I've dislodged it through, err, spirited driving, sending the phone flying across the cabin.   A cage-type mount would probably be better, though it's better than any other solution like having it in the console, particularly when you want to use navigation.

That's it for now - I'm currently working on moving the equalizer from it's current location on top of the console to make way for a new AC Vent.

[Coastr]

As previously mentioned the next project was to move the equalizer from it's location on top of the centre console to somewhere more suitable.  I needed the space above the centre console to mount the new center AC vent.  And it was too far away from the driver on top of the console to ever 'play' with it.  Though the idea of an equalizer is an outdated piece of useless 80s tech anyway.  But they look so period correct!

There were two problems I wanted to solve with the equalizer move - 1) to tuck it up under the dashboard next to the ashtray; 2) to get rid of USB power supply tucked into the cigarette lighter (only way to power the phone for long distance maps driving).   I also didn't want to drill any holes in anything.
I created a model to 3D Print and it looked something like this:

The idea with the design is the top of the face has a hook - this sits on the bottom steel rail of the dashboard, up behind the dashpad.  The oval hole at the back is for the wires of the equalizer to go out- originally I had a rectangular hole but problems with shrinkage and warping led to 6 failed prints.  Always learning with this stuff.  The hole up the top is for an off-the-shelf round USB charger.  The little holes are there for zip-tie mounting, both to hold the back and also to act as ties for all the wiring.

Here it is finished on the printer - I wound the speed back and did some other tuning - total print time was 23 hours

And here's it separated from the print bed, with the USB charger inserted in the side:

The gap running under the lip is messy because of the way it printed, it had removable support in there which I removed with a screwdriver.

Here it is with the equalizer inserted and ready to go into the dashboard, but not yet wired up for the USB charger.

 

Originally I planned to print a face plate for the front, but I don't need it because the bottom of the dash pad hides it, and it's stronger than I thought it would be.

Putting it in was as simple as hooking it up under the dash and then securing the back off the same strap that holds the back of the head unit up.  The equalizer can wobble a little bit but I don't mind as it's possible a passenger leg could bump it, i'd rather it moved when that happens.  It only moves about 10mm laterally.

Here's the finished mounting:

I put the subwoofer level control back under the ashtray as another temp measure (there's an old hole drilled there), I'm probably going to make a similar mount for the driver side.  Or even investigate if I can re-use the factory fader knob as a level control for the sub.    It doesn't look like it, but the equalizer mounts vertically aligned with the right hand side of the head unit, so it kind of lines up.

The USB Charger works great and I routed the wire up through the back of the ashtray, and coiled the wire inside the ashtray.  Because the charger has two outlets I mounted another charging wire and coiled that up in the ashtray as well.  This means there's a charging cord for passenger if needed.  But both hidden away.  I can pull it out and charge the phone with the short run from ashtray to phone mount

So this is mostly it for the audio project, except that pesky subwoofer control.  I do use it a bit though - listening to podcasts sucks with too much bass while listening to music is great.  I *can* use my equalizer to take the bass out though - so much 80's audio tuning fun to be had.

[60beetle60]

How's the upgraded audio gear been performing? 

Interested to know if you'd recommend the underseat sub or if you'd go something different starting again.

I've been thinking of adding in an underseat sub to my 911sc to go with the new blaupunkt sqr46 and upgraded door speakers I recently installed. I've been looking at a kenwood sub, KSC-PSW8, but if yours is performing well I might go the same route.