# DSP Control Module / Amplifier



## oca123 (Jan 14, 2012)

Hi all,

In the 12-speaker system, the J523 sends audio to the DSP/Amplifier module in the trunk, and some CAN bus signals. The DSP/Amp then takes care of volume, PDC sounds, etc.

I am planning a sound system installation and have decided to keep the 12-Channel amp in order to keep PDC, volume, etc.

I'm going to connect the speaker-level outputs of the factory amplifier to an Audison BitOne, which will then be able to sum and de-equalize the signal and give me a signal very very close to a full-range, flat signal. The Bit One can only accept 8 input signals, so I will probably give it Front highs, front mids, front lows, and rear mids.

My questions are:

- I've seen diagram 35 posted by PanEuropean, however my car is actually a 2005 CGT. Does anyone know which color wires I will need to cut from the factory amplifier to make this work?
- Does anybody make a harness or connector that will fit into the amplifier? Either a blank connector or a pre-wired harness would work.

Thank you for your time in advance.

Paul


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## jkuisma (Nov 23, 2009)

Would it make more sense to reprogram the J523 to 8-channel operation and ditch the DSP box completely? There are individual speaker outputs in the back of the J523. And - as far as I can remember - they are volume controlled by the head unit in case there is no DSP. Just a thought.

Jouko


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## oca123 (Jan 14, 2012)

Hi Jouko,

I have thought about this option but was not able to find (or maybe it was in front of me but I was not able to understand it) anything on this.

Since the car here is actually a Bentley Continental GT, which never came with an 8-speaker system, I am not sure whether this is possible and how to even recode it with a VAG tool.

Can someone say with almost 100% certainty that it can be done? I am in southern california and OEMPlus is actually not too far. Maybe they would know and would be willing to recode the HU?

Paul


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## jyoung8607 (Feb 14, 2006)

I studied this recently, because I'm looking into a "car-puter" project for my Phaeton. I think the wiring diagram only shows the Infotainment unit sending stereo-only audio to the amp. It also lists separate outputs for nav, phone, etc. The amp also generates tones for park distance controls, which I ass-u-me is done by listening to CAN commands. This all pretty much implies the expansion from 2 to 12-channel with associated mixing is done by the amp, and balance and fade is handled using CAN instructions along with which DSP effects to apply for the DSP amp.

Both the DSP and standard amps appeared to do it the same way based on my limited research, although the standard amp wouldn't have DSP effects available.

I'll dig up the wiring diagrams a bit later this evening if Michael doesn't beat me to it.

Jason


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## oca123 (Jan 14, 2012)

Here's the wiring diagram. I uploaded it to scribd - http://www.scribd.com/doc/78691841

I would venture to guess that recoding the HU would result in different gain being applied to the audio outputs, but would still result in loss of PDC signals, etc.


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## jyoung8607 (Feb 14, 2006)

Looks like the wiring diagram is covered. Here's another document showing pinouts at the amplifier for ease of reference, and a functional diagram of audio feeds. The harness-side of the connector could probably be looked up and ordered, but I'm not sure about the amp-side, which you'll need as well.

I think you have an uphill climb ahead of you. You can capture full spectrum stereo audio in front of the amp, but you will lose Infotainment control of volume, balance, fade and DSP effect and you won't get PDC beeps, and I believe you'll lose navigation audio. After the amp, you'll have all the functions but not necessarily the audio spectrum. You mentioned you don't have enough inputs to process all twelve channels. As you say, you could get a lot by collecting six of the eight front channels and two of the rear four. I don't know if there is combination of six front channels that will let you recover full spectrum audio (I don't know how much they overlap) and the DSP effects will probably be way off (although I doubt you care), so you'll have to run in Neutral. I also don't know if the PDC beeps and nav audio make it to all four front-side speakers, so you may not get to eliminate a certain channel even if you want to. You'll lose quality in the rear because neither the bass nor the mid-bass are likely to overlap enough to recover a full rear signal. If you're willing to give up Infotainment control of front/rear fade, you could use all eight of your inputs on the front and use that to regenerate the rear, again definitely breaking DSP effects but gaining some quality.

If the Bentley was never made with the low-line 8 channel amp option, it's not at all clear whether its Infotainment unit will talk to it. They communicate by CAN network messages. The VW Infotainment unit will change certain screens and options based on what amp is installed. The Bentley Infotainment unit uses a modified version of the very same software, but that version may have never been taught about 8 channel amps.

I have to ask, why do you want to do this? Not condemning, but I can't imagine what you're trying to do that more audio processing is going to help. The Phaeton's audio system (and I think the Bentley version is the same) is universally regarded as one of the best factory audio systems ever put out there. The sound fidelity is just absolutely amazing. Some people prefer more bass, it's true. But if that's all you need, just borrow two of the four bass speaker channels. They're are already band-pass filtered for you in a way compatible with the rest of the system, which will be quite low since you have dedicated mid-bass and midrange. You bring that into your additional amp and speakers, put them wherever you like and you keep full OEM operation and appearance.


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## oca123 (Jan 14, 2012)

That's what I thought. I think I will capture the signal after the amplifier and use the Audison Bitone to de-equalize it and turn it back into a flat, full range signal.
The way this works is you set the HU to Neutral, disable compression and loudness, and put a CD containing test tones and sweeps in the CD player. You hook up the BitOne to the amplifier outputs and initiate the calibration. The BitOne will analyze the sound it receives and figure out what EQ is needed to obtain a full range signal again, then apply it.

Because the crossovers in the stock amplifier have a curve (e.g. 12db/octave, 24db/octave, etc.) the bitone will be ale to generate a full range signal off of the post-amp signal.

The reason I am doing this is because I have had and installed after-market systems in several of my cars and no stock system even compares to the custom systems I have had, including the 12-speaker Bentley sound system. The NAIM sound system in the Bentleys (which is an $8000 option) does sound excellent (I heard it at a dealer), and still, my last aftermarket system was a lot better.

I just got done taking the door panels apart and will be applying dampening materials. The doors have a 6.5 mid (for the rear,) a 6x9 and a 3'' midrange driver. I will be installing a Focal KRX3 set in the front (3 inch mid, 6.5 inch woofer, and 1 inch tweeter) and another one in the rear. I will build an adapter plate to install the 6.5inch woofer in the 6x9 location.

Since the Bentley has a ski-pass, I will also be installing a subwoofer in the trunk, sealed to the backseat and firing through the ski-pass. I have a JL W7 12'' sub laying around, and a Boston Acoustics SPG-555 - have not decided which one will go in yet.

I can guarantee you that the resulting system will be heaps and bounds better than the stock system.

Thank you so much for the amplifier pinout. It is very clear. Based on what I am seeing, it will make no sense to try to purchase connectors or harnesses, since VW put input and output on the same connector, instead of using one separate connector for speaker outputs only. I guess I will have to cut the wires, unless you can recommend a different option.

Cheers

Paul


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## jyoung8607 (Feb 14, 2006)

oca123 said:


> That's what I thought. I think I will capture the signal after the amplifier and use the Audison Bitone to de-equalize it and turn it back into a flat, full range signal.
> The way this works is you set the HU to Neutral, disable compression and loudness, and put a CD containing test tones and sweeps in the CD player. You hook up the BitOne to the amplifier outputs and initiate the calibration. The BitOne will analyze the sound it receives and figure out what EQ is needed to obtain a full range signal again, then apply it.
> 
> Because the crossovers in the stock amplifier have a curve (e.g. 12db/octave, 24db/octave, etc.) the bitone will be ale to generate a full range signal off of the post-amp signal.


Sure, I'm familiar with the task. You're taking the factory amp's output signal, and using this box and the calibration process, establishing how the factory amp "tampers" with the sound and then using its DSP to reverse those changes, getting back to a neutral clean signal for further processing. It neutralizes the factory equalizer.

The challenge is, it can't synthesize input signal that isn't there. Bass frequencies aren't coming out the tweeter, and vice versa. Between the tweeter, the mid, the mid-bass and the bass there might be some overlap, but probably not total overlap. If you're missing a frequency band, your DSP can't recreate it. In other words, if the factory EQ under-emphasizes a certain frequency by 25%, your DSP can take that and amp it back up to 100%. Same thing in reverse for signals that are over-emphasized. But, if the factory EQ attenuates a certain frequency by 100%, that signal is gone, there's nothing there for it to work on. That's what you may run into if you're missing one of the band-passed channels.



> The reason I am doing this is because I have had and installed after-market systems in several of my cars and no stock system even compares to the custom systems I have had, including the 12-speaker Bentley sound system. The NAIM sound system in the Bentleys (which is an $8000 option) does sound excellent (I heard it at a dealer), and still, my last aftermarket system was a lot better.
> 
> I just got done taking the door panels apart and will be applying dampening materials. The doors have a 6.5 mid (for the rear,) a 6x9 and a 3'' midrange driver. I will be installing a Focal KRX3 set in the front (3 inch mid, 6.5 inch woofer, and 1 inch tweeter) and another one in the rear. I will build an adapter plate to install the 6.5inch woofer in the 6x9 location.
> 
> ...


Hmm. If you have a 6x9 in your front door, your system differs from the Phaeton. The bass and mid-bass are the same size in our cars. The wiring may still be close enough to use ours as a reference.

I looked up that Focal KRX3 set you mentioned. That's... well, it /is/ for a Bentley I suppose. 



> Thank you so much for the amplifier pinout. It is very clear. Based on what I am seeing, it will make no sense to try to purchase connectors or harnesses, since VW put input and output on the same connector, instead of using one separate connector for speaker outputs only. I guess I will have to cut the wires, unless you can recommend a different option.


The block diagram I posted above implies the DSP spits out four channels, front left/right and rear left/right. Those go to the amp output stages, and it implies the amp output stages have the crossovers for that corner. Now, the block diagram is a long way from a circuit diagram, and the output stages seem to have some intelligence - onboard diagnostic fault codes are available for open-circuit to any of the twelve speakers. But, if you're hard-core, you might open up your amplifier and see if you can find the full-spectrum amp DSP outputs before they get to the amp output stages. That would give you much simpler, full-spectrum low-level inputs to your post-processor DSP. You'd even be able to to use the factory DSP driver-optimized, surround, etc effects if you're ever in the mood.

Jason


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## oca123 (Jan 14, 2012)

Hi Jason,

I highly doubt that the factory DSP attenuates any single frequency to 100%. That would create phase problems, etc.
What's more likely is 12db/octave filters. I will install the BitOne and see what happens. The other thing is, the BitOne has tons of inputs, from regular RCA left/right inputs to digital to TosLink so I will be using a direct optical input into the BitOne with a portable media player that has an optical output.

I absolutely do NOT want to use the factory DSP. It will not work with the new speakers. The BitOne lets you do t/a, eq, etc. and I will be able to achieve much better results using that.

I've decided, after taking the door panel out, to get a 2nd set of KRX3s. So one for the front and one for the rear. They will sound very good in this car, once I equalize and time-align them.


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## oca123 (Jan 14, 2012)

As to the open-circuit warnings, I doubt these actually generate beeps and errors when you start the car or drive it around, but they will probably generate codes you can look up with a VAG or something, so no big deal. In any case I can hook up resistors or something to the signal outputs I wont use.


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## jkingdoc (Apr 3, 2010)

*Adding Sub for fuller spectrum?*



jyoung8607 said:


> Looks like the wiring diagram is covered. Here's another document showing pinouts at the amplifier for ease of reference, and a functional diagram of audio feeds. The harness-side of the connector could probably be looked up and ordered, but I'm not sure about the amp-side, which you'll need as well.
> 
> I think you have an uphill climb ahead of you. You can capture full spectrum stereo audio in front of the amp, but you will lose Infotainment control of volume, balance, fade and DSP effect and you won't get PDC beeps, and I believe you'll lose navigation audio. After the amp, you'll have all the functions but not necessarily the audio spectrum. You mentioned you don't have enough inputs to process all twelve channels. As you say, you could get a lot by collecting six of the eight front channels and two of the rear four. I don't know if there is combination of six front channels that will let you recover full spectrum audio (I don't know how much they overlap) and the DSP effects will probably be way off (although I doubt you care), so you'll have to run in Neutral. I also don't know if the PDC beeps and nav audio make it to all four front-side speakers, so you may not get to eliminate a certain channel even if you want to. You'll lose quality in the rear because neither the bass nor the mid-bass are likely to overlap enough to recover a full rear signal. If you're willing to give up Infotainment control of front/rear fade, you could use all eight of your inputs on the front and use that to regenerate the rear, again definitely breaking DSP effects but gaining some quality.
> 
> ...


I would like to add a sub (not for loudness necessarily) to my 04 V8 full DSP phaeton's audio system. If I went to a shop with theory and diagram in hand, should I be able to get sub added and keep my current functionality? I'm sure this is a stupid question? Would love an answer though.
Thanks, 
Johnny


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## jyoung8607 (Feb 14, 2006)

oca123 said:


> Hi Jason,
> 
> I highly doubt that the factory DSP attenuates any single frequency to 100%. That would create phase problems, etc.
> What's more likely is 12db/octave filters. I will install the BitOne and see what happens. The other thing is, the BitOne has tons of inputs, from regular RCA left/right inputs to digital to TosLink so I will be using a direct optical input into the BitOne with a portable media player that has an optical output.
> ...


So 100% was probably an exaggeration, but the vast majority of the undesired signal at any given speaker position will get disappeared by the crossover. Your DSP setup will definitely work great if it's given all the pieces. But you're already paying the cost of A-D-A-D-A conversion with the unavoidable analog generation noise. Missing a channel and depending on recovering highly-attenuated signal from the others? From speaker-level audio outputs with a higher noise floor, so you'll have awful SNR for the attenuated band especially at low volume? You seem to know what you're doing and it's your car, I'm just trying to help find the best way to get clean audio.

I still think you should look into disassembling the Bentley amp and picking up line-level audio after its DSP but before the amp output stages. I don't know for sure if it's possible. You could pick up a spare/salvage donor if you're afraid to experiment on the one you have. Whether or not you ever run its own DSP effects, that is theoretically where you're going to find the best and cleanest full-function input for your BitOne.

Anyway, like I said it's your car and I'll step out of it from here.

Direct hookup to a portable media player will sound fantastic, of course. But if you go around the Infotainment unit, you'll need your own volume control. That means you're committing to mounting your DSP control in the cabin somewhere you can access it. If you were already planning on it, that's fine, just didn't know if you were aiming for stealth/OEM look and function.



> I've decided, after taking the door panel out, to get a 2nd set of KRX3s. So one for the front and one for the rear. They will sound very good in this car, once I equalize and time-align them.


Wow! If you weren't on the other side of the country, I'd want to come see this when you're finished.


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## jyoung8607 (Feb 14, 2006)

jkingdoc said:


> I would like to add a sub (not for loudness necessarily) to my 04 V8 full DSP phaeton's audio system. If I went to a shop with theory and diagram in hand, should I be able to get sub added and keep my current functionality? I'm sure this is a stupid question? Would love an answer though.
> Thanks,
> Johnny


Not a stupid question at all, it's a complicated car.

If you take those documents to any competent installer, especially the amp pinout and the block diagram, they'll know exactly what to do. They'll probably take a pair of the bass speaker outputs and use an amp with speaker-level inputs to power the sub. If they unhook the cabin bass speakers to do it, they might hook them back up through the new amp. If they want to run power direct from the battery, it's close by right there in the trunk. However, make sure they do it from the vehicle power supply battery (left) and not the starter battery (right).

Jason


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## oca123 (Jan 14, 2012)

It might not sound very good. Your trunk sub needs to only play notes below 75Hz-ish in order to blend in with the system. Notes over 75Hz will be too high to be just bass and you will be able to tell that there is a sub in the trunk, and they will sound muddy.



jyoung8607 said:


> Not a stupid question at all, it's a complicated car.
> 
> If you take those documents to any competent installer, especially the amp pinout and the block diagram, they'll know exactly what to do. They'll probably take a pair of the bass speaker outputs and use an amp with speaker-level inputs to power the sub. If they unhook the cabin bass speakers to do it, they might hook them back up through the new amp. If they want to run power direct from the battery, it's close by right there in the trunk. However, make sure they do it from the vehicle power supply battery (left) and not the starter battery (right).
> 
> Jason


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## jyoung8607 (Feb 14, 2006)

oca123 said:


> It might not sound very good. Your trunk sub needs to only play notes below 75Hz-ish in order to blend in with the system. Notes over 75Hz will be too high to be just bass and you will be able to tell that there is a sub in the trunk, and they will sound muddy.


It's true the crossover point may not be perfect without tuning, but I was mainly referring to the technical means to integrate with the car. A competent installer would help him with speaker selection, enclosure selection and crossover point selection if additional high frequencies need to be peeled off. Using the bass speaker outputs as his new amp input obtains the right audio signal, even if you throw away some of that input later in the chain.


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## Paximus (Aug 26, 2011)

I would love to hear a fully equipped and properly acoustically equalised sound system with a flattened phase response in the car, if such a thing is remotely possible with so many speakers. 

Many after-market sound system 'enhancements' are tuned for dance- or rap-style satisfaction, but this vehicle platform deserves a really serious treatment.

My standard 8-channel audio has a mid range imbalance and a discrepancy between CD quality and FM quality. It's still very high 'fidelity' (remember that?) but I can see why the factory upgraded to the 12-channel system.

What the BitOne system can achieve I can only dream about. These techniques were science fiction when I first went to audio demos that sold kit I couldn't conceivably afford on my teenage paper-round earnings!

Good luck with the projects. I'm all agog.

Chris


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## oca123 (Jan 14, 2012)

Agreed. Using the diagrams above, a competent installer would have no problem integrating a subwoofer into the system.


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## oca123 (Jan 14, 2012)

I am still debating which speakers to throw in the car.



Paximus said:


> I would love to hear a fully equipped and properly acoustically equalised sound system with a flattened phase response in the car, if such a thing is remotely possible with so many speakers.


The problem with so many speakers is not a "flat" response, it's the phase errors that occur when crossing over so many speakers in so many different locations. The best sounding systems typically have a tweeter and a woofer in the front, and a subwoofer, period.
Additionally, a flat response never sounded good, but it is a good starting point to then apply mild EQ.



> Many after-market sound system 'enhancements' are tuned for dance- or rap-style satisfaction, but this vehicle platform deserves a really serious treatment.


Agreed



> What the BitOne system can achieve I can only dream about. These techniques were science fiction when I first went to audio demos that sold kit I couldn't conceivably afford on my teenage paper-round earnings!


The BitOne is pretty amazing. JBL also makes a processor called the MS8, which uses "stereo microphones" you put on your ears (binaural microphones) to measure and adjust the frequeny response and phase in the car. I have owned a couple of MS8 units and they are great if you want to be up and running quickly, but they take out a lot of the fun of measuring and EQ'ing things yourself.


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## Paximus (Aug 26, 2011)

I always think setting up a sound system yourself is a two-edged sword - you _know _it sounds far better than it did, because you've worked hard to achieve that, but on the other hand you always know that there is more you could or should do!

If someone else does it, you shrug your shoulders and get on with listening to the audio content...

Cheers,
Chris


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## oca123 (Jan 14, 2012)

I respectfully disagree. What drove me to install my first system was hearing someone else's.
And whenever I hear a custom system, I close my eyes, pay close attention and appreciate all that has been done.


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## Paximus (Aug 26, 2011)

Good point. When you hear truly good sound, it is stirs the soul. Which is why this platform deserves it. Hope it all works out to your immense satisfaction...

Chris


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## EnglishPhaeton (Dec 6, 2010)

oca123 said:


> I respectfully disagree. What drove me to install my first system was hearing someone else's.
> And whenever I hear a custom system,* I close my eyes, pay close attention and appreciate all that has been done*.


 Hmm, 

this could be a little dangerous 
I work in the audio industry and I have to (respectfully) point out that the amp/speaker package is the LAST part of the audio chain. Are you intending replacing the source? If not you are only really changing the sound quality, you are not necessarily improving it. In my opinion the weakest ling in the Phaeton/Continental is the "integration". 

Stu


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## Zaphh (Jul 5, 2008)

Jules Renard, a French writer, once said "It was so beautiful that I closed my eyes"...


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## EnglishPhaeton (Dec 6, 2010)

Zaphh said:


> Jules Renard, a French writer, once said "It was so beautiful that I closed my eyes"...


 Pierre, 

I believe that he also wrote; 

If I were to begin life again, I should want it as it was. I would only open my eyes a little more. 

Stu


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## oca123 (Jan 14, 2012)

EnglishPhaeton said:


> Are you intending replacing the source? If not you are only really changing the sound quality, you are not necessarily improving it. In my opinion the weakest ling in the Phaeton/Continental is the "integration".
> 
> Stu


Absolutely. I ended up using a computer as the source, with an Edirol FA101 as the sound card. The computer uses a chain of VST hosts to perform various sound processing tasks. The bulk of the processing is done via a convolver doing digital room correction via FIR filters.
The source from the stock HU is mixed in, but there is a gate that only lets sound through if it is over a certain threshold. That threshold is set above the floor noise level. The reason I have the HU hooked up at all is to be able to hear park distance control tones, and the occasional navigation prompts.

The system can only fully be appreciated when parked. Once you are driving, the noise floor goes up, your signal to noise ratio goes down, and, well, it is dangerous to close your eyes 
I plan on adding more sound deadening to the car, in the form of lead tape. This should help with the SNR.

Paul


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## oca123 (Jan 14, 2012)

EnglishPhaeton said:


> Pierre,
> 
> I believe that he also wrote;
> 
> ...


And I believe La Fontaine's crow closed his eyes and lost his cheese to the renard (fox)


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