I have a 2011 997.2 GTS with PCM 3.0+Bose and would like to replace the speakers and amp while retaining the head unit.

The first step is going from the current config to analog line level outs.

As we all know, this is not straightforward due to the MOST bus connection from the head unit to the Bose amp.

Can anyone advise on the different ways to do this and what appears to be the best practice.

I was thinking of a few ways:

1)Line level converters from the speaker outputs of the Bose. This is potentially problematic as I do not think there is a full range speaker level output from the Bose amp and the Bose amp likely includes some processing. Perhaps I could use a processor to sum the various speaker level signals and give me full range, but this seems a bit prone to quality degredation.

2)convert the MOST head unit output to line level. MOBRIDGE makes a preamp that appears to give me analog out:

http://www.mobridge.us/products/most...analog-pre-amp

The 997.2 is not on the compatibility list, but similar head units are and I suspect it will work.

3)Concert MOST to Toslink and then use a processor to go from Toslink to the amps - this gives me an all digital solution into the processor and would probably be the cleanest solution. The linked Mobridge unit appears to do this - again, not sure of compatibility.

http://www.mobridge.us/products/most-digital-pre-amp

Other thoughts?

 

Call Al & Eds in Marina del Rey,CA and ask for Shane ( I believe that's his name ). You will get great information from him regarding what you want to do.

Good luck!

 

I think these guys can send you a kit too.

[QUOTE=dbbarron;3986886]

Yes, you can do this. You'll need an "integration processor" that accepts all the speaker-level signals, combines them, and spits out a flat signal. I've done this exact setup (997.2 Bose amp out to processor to amps) with the JBL MS-8. It's actually works pretty well, but the signal-to-noise ratio isn't great - meaning when the engine is off, you can hear the faint noise level. I ended up "upgrading" the head unit because I didn't like how the Bose system changes the EQ based on vehicle speed.

I think I checked on this particular unit a while back and it's not compatible with the 997.2, but ask them they might have an update.

This one I think I also checked on and it's not 997.2 compatible either. But they might have updated it. Better ask them.

When I was looking for a similar solution (i.e. factory bose HU for 997.2 -> line out signal), I couldn't find anything other than tapping the Bose amp outputs and processing them. There are products to keep your Bose amp/speakers and stick in an aftermarket HU, I couldn't find anything for the Bose HU with aftermarket amps. I was pretty happy with the MS-8, but I ended up upgrading the HU as well. good luck let us know what you find

 

Hi,


I can shed some light here: I have Sound Package Plus and PCM 3.0 and am looking for better audio too.


What I know is on pre-facelift cars (PCM 2.1) the PCM was different whether you had base audio/SPP (speaker level out) or BOSE (optical out). With facelift cars (PCM 3.0) the PCM has two variants also (single CD or 6CD changer) but both support analogue line out and optical out via MOST BUS. Given that Mobridge's DA-1 currently doesn't work with PCM 3.0 (I mailed them a few months ago and they said it'll be ready by the end of this year but no joy as yet) your best option is to have the PCM 3.0 unit recoded for Sound Package Plus (get your dealer to do this), then solder a high quality RCA to the analogue outputs of your PCM and connect this into a processor like the Audison Bit One or Helix C-DSP or Arc Audio PS8 or Mosconi 6to8 or Alpine PXA-H800 or whatever else floats your boat. From here, set up the EQ/time alignment to each output channel, send the outputs into an amp of your choice (I'm using a JL Audio HD amp) and then off to your speakers.


If you don't fancy going the analogue route, then hold on for Mobridge to begin supporting the PCM 3.0 then you'll be able to take a TOSLINK cable from the DA-1 straight into your chosen processor - from there on it's the same as above.


N.B. PCM 2.1 was speaker level out. PCM 3.0 is line level out (I found this out the hard way).

 

CRXVTEC:

Thanks so much. I have my local dealer checking with MoBridge on PCM 3.0 compatibility now, so we will have the up to date word soon on compatibility. My plan was to go from the MoBridge Toslink output to a Audison Bit 10D; digital all the way through.

I had no idea PCM 3.0 had line level outputs. Do you have a pinout of the rear panel with these outputs? A picture would be nice to. Is there a connector available rather than soldering? Guess I need to see the rear panel to understand the job. That would remove the MoBridge unit, but introduce an additional A/D--D/A path. Likely little impact overall at line level.

Is there a single full range line level (stereo pair) output on the PCM 3.0 in Sound Package Plus mode, or are you using the processor to sum various frequency outputs? I am a bit reticent to sum limited band outputs to achieve a full range signal.

Is the recoding complex or just a few minutes on the computer for the dealer?

Regards
db

 

I would highly recommend swapping the speakers first and running with the Bose amp. If you are unhappy with the results, then you could always add the amp and EQ. The EQ and amp road is much more complex. The results will probably be better, but you may not find it worth the extra complexity and cost.

 

Hi DB,


If you want the full digital path, you'll want to use a BitOne and a Voce amp with AV Bit IN - this places the DACs inside the amp.


I don't have a photo with pinouts however you can get a connector - I use a SOT harness which basically gives you a M-F harness you can insert between the car's loom and the PCM. You can then cut and solder this so there is zero touch on the factory loom. The style of connector is QuadraLock - a system developed by Fakra and used by many German manufacturers. If you get a VW or Audi compatible QuadraLock SOT harness, you'll be good to go.


You will get 4 full range channels out of the PCM so no summing needed. I used the front pair only into the BitOne.


Recoding with a PIWIS should be easy, though once done I expect the BOSE amp will no longer work. If you do go for the DA-1 in future, you will need to recode the PCM back to BOSE.


Cheers,


C.

 

You have to consider the Bose amp is weak, optimised for the Bose drivers at their low impedance and also equalised so applying generic speakers are unlikely to yield excellent results. It would in fact be preferable to keep the Bose drivers and give them some real amplification, but at the expense of not knowing the best crossover points and slopes - hence it is better to design the system with a clean sheet and a clean, preferably digital, source.

 

Unlikely is the key word. Check with the other guy on my thread that did the conversion. You'd be surprised. No arguments on a clean digital source of course. Gotta run clean files through an ipod using a Dension or NavTV.

 

You sure this harness can give you an analog line-out signal from the Bose PCM 3.0?

 

It's working in my car. IF you have the BOSE system you'll need the PCM recoded for Sound Package Plus or Base audio system. Voltage is <3V.

 

CRXVTEC:
I assume out of the harness there are 4 pairs (frontL/rearL;FrontR/rearR) with one conductor being signal and the other being the shield/ground; or is there a common shield/ground; or are they a differential pair? If standard signal+shield/ground, assume you soldered these to standard RCA connectors and then ran to your amp. How did you figure out which connector is which? Is there a standard quadraloc pinout or did you use a scope?

db

 

I found multiple references online to the pinout including the following:
(see article - ignore initial picture)
http://en.wikipedia.org/wiki/Connectors_for_car_audiohttp://www.fordwiki.co.uk/index.php?...tor_-_Facelift

Standard pair, + to tip of RCA, - to shield.
Too easy.....

db

 

Hi DB,


It is 4 pairs. The pinouts match the ISO configuration used universally; more info here: http://en.wikipedia.org/wiki/Quadlock#Quadlock


I had just the front pair soldered to RCAs and run to the amp - naturally it's preferable to solder these as close to the plug as possible so that there's less of the inferior connector cable and more RCA over the run length.


Cheers,


C.

 

Just a thought - if you have a scope/voltmeter, see if there is a signal present before you re-code the PCM. It may save you some time and energy.