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Discussion Starter #1
Let's face it. The CD based Nav in the 2004 Touareg was outdated in 2004. By today's standards it's downright archaic. One of the most well known problems (and disappointments) of any 2004 Touareg owner looking to upgrade the factory stereo is that the digital amp that VW decided to use is a major roadblock to any uprgrade as it usually involves rewiring the whole car by replacing all the speakers and having them powered by external amps. The reality for anyone that chose to upgrade without rewiring is that you lose sound from 7 out of 11 of the factory speakers, which to be honest sounds terrible.

Well, after weeks of testing and scraped knuckes, I am proud to say that I have a working solution! I am able to achieve sound from all 11 speakers, driven by the 4 channels of the Android Head unit that I have installed in the dash. Right/Left/Front/Rear fading and balancing works as expected too and I can honestly say that the audio in my Touareg has NEVER sounded better! :):)

I'd be happy to share the details if anyone's interested but since It's late and I am tired (and cold) I am off to bed and can share more details in the morning.
 

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OK, here's the solution:

Just to recap: The CD Nav on the 2004 Touareg has 11 speakers. 7 in the front (1 mono center speaker) and 4 in the rear. If you knew the pin-outs from the factory amp located in the rear, you can easily tap into the existing wiring from a 4 channel amp, (i.e head unit) to drive all 11 speakers.

The problem with this is that when you connect speakers in parallel the impedance seen by the amplifier is divided among the total amount of speakers connected. All of the speakers in the Touareg represent a 4 ohm load so by my calculations:

Wiring all front speakers in parallel to a 2 channel amp would result in a 1 ohm load being seen by the amplifier

Wiring all rear speakers in parallel to a 2 channel amp would result in a 2 ohm load being seen by an amplifier.

The reality is that most (if not all) head units are designed to handle a minimum impedance of 4 ohms. Any lower and you will overload the amp and damage it.

So to solve this problem I implemented 2 impedance matching circuits between the front and rear speakers and the head unit amplifier. From there, the wires are split into the required 22 individual wires that are then patched directly into the factory wiring harness for distribution to all 11 speakers. By doing so, I am able to connect all 11 speakers to the head unit in parallel using only the 4 channels of the amp (2 front and 2 rear) all the while keeping the head unit's amp within it's safe operating range by presenting the amp with no less than 4 ohms through an impedance multiplication switch on the impedance matching volume controls.

I've attached some photos of the design I came up with along with the physical photos of the hardware in question. In case anyone is wondering why there are only 2 wires on the input side (white wires) going into the wiring network box, it's because each white cable contains the 4 wires required for front-right, front-left, rear-right and rear-left speakers.

While the 'finished' product is not pretty it works 100% and I am able to fully control fading and balance independently between the front and rear/left and right. I did plan on going back and building a better looking version of my wiring network based on my working prototype but since it works so well and I'm going to be permanently hiding it out of sight behind the right rear trunk panel I honestly don't see the point.

From a performance standpoint I am really blown away! The sound stage is wider and clearer than the factory head unit and I am impressed with the sonic quality of the factory speakers. To get the most of the speakers I installed Viper for Android on my head unit. A demo of the software can be seen here:

If anyone has any questions regarding the set up I'd be happy to help. I'm just happy to finally be enjoying a modern head unit in my Touareg with sonic quality to back it up.
 

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Discussion Starter #4
Thought I would include a video of the sound system in action. Keep in mind this was recorded from a cell phone which tends to exaggerate the bass from the track but in the car it sounds clean and low to my ears. This is best heard if your computer has a subwoofer.

 

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Discussion Starter #5
Here's another audio test from last night before I mounted the unit. The background hiss is from the fan in the head unit and not from the speakers.

 

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Thanks for sharing!
The original digital amplifier was bypassed and use the head unit's built-in amplifier to drive 11 car speakers.
A couple of questions:
1. Do you know the power range of the 11 car speakers?
2. Do you think the wiring network box can be replaced by a one to three frequency divider?
I am working on this issue and appreciative for your sharing!
 

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Discussion Starter #7
Thanks for sharing!
The original digital amplifier was bypassed and use the head unit's built-in amplifier to drive 11 car speakers.
A couple of questions:
1. Do you know the power range of the 11 car speakers?
2. Do you think the wiring network box can be replaced by a one to three frequency divider?
I am working on this issue and appreciative for your sharing!
No problem! To answer your questions:

1. Sound System II which is the CD based NAV is rated at 400 Watts for 11 speakers. By my math that would mean that the factory amp is pushing roughly 35 watts per speaker. I don't know what the power ratings of the speakers are but I'd guess that Volkswagen would have added some buffer which means they should be able to handle 45-50 watts of clean power.

2. To be honest I'm not sure, but I am sure that a more elegant solution could be developed with a little bit of time, effort and of course money. As for me, I'm likely going to live with this set up for a while since it works flawlessly. When it gets warm and I have nothing better to do I may spend some time developing a version 2 of my solution.

I'm looking forward to seeing what you come up with!
 

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Now this thread is an exciting one to see!

Thanks for the answers!
Any details of the stuff packed with adhesive tape?
I would guess those are resistors to implement the required impedance of the calculated load. It would be nice to know the values since you've already done the work for us.

A couple questions I have are:

1) Could you provide us with a more specific wiring diagram? I'm curious if you took into account that the tweeters and subs are probably different impedances (though they don't have to be), and I'm assuming these sub/mid/tweet speaker chains are the one's you've calculated directly.

2) What's the use of the rheostat switches? Is this your control for the impedance matching vs power required?

3) I'm guessing you have bypassed the digital amplifier to do this. That gives me a couple concerns I'm wondering if you have addressed:

  1. Did this also bypass the band limiters to the speakers (limiting low from the mid and tweeters etc...) Sending 50Hz to your tweeter would not be good. I'm guessing either the filter is located down stream of your system or you have addressed it somehow since you still have a system.
  2. Does the new head unit have enough power? Your estimates for the speakers (~50W) are very low even for factory speakers and I would guess that these are probably not being driven with the amount of power they should. This won't be a problem till the volume knob gets turned up.
3) Couldn't an amp out signal from the head unit be used as inputs to the factory digital amp? I'm guessing not since that would be too easy and someone would have done it by now.
 

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Are the two white cables twisted-pair cable? If so, maybe look into using baluns or specific wiring patterns to use to avoid issues. This guy has some interesting cat-5 audio cable designs. :)
 

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Discussion Starter #12
Now this thread is an exciting one to see!



I would guess those are resistors to implement the required impedance of the calculated load. It would be nice to know the values since you've already done the work for us.

A couple questions I have are:

1) Could you provide us with a more specific wiring diagram? I'm curious if you took into account that the tweeters and subs are probably different impedances (though they don't have to be), and I'm assuming these sub/mid/tweet speaker chains are the one's you've calculated directly.

2) What's the use of the rheostat switches? Is this your control for the impedance matching vs power required?

3) I'm guessing you have bypassed the digital amplifier to do this. That gives me a couple concerns I'm wondering if you have addressed:

  1. Did this also bypass the band limiters to the speakers (limiting low from the mid and tweeters etc...) Sending 50Hz to your tweeter would not be good. I'm guessing either the filter is located down stream of your system or you have addressed it somehow since you still have a system.
  2. Does the new head unit have enough power? Your estimates for the speakers (~50W) are very low even for factory speakers and I would guess that these are probably not being driven with the amount of power they should. This won't be a problem till the volume knob gets turned up.
3) Couldn't an amp out signal from the head unit be used as inputs to the factory digital amp? I'm guessing not since that would be too easy and someone would have done it by now.
Hi guys,
Those are simply butt connectors. One end has the wires coming off the impedance matching volume control the other end contains the wires that are patched into the factory wiring to the speakers.


To answer your questions:

1: I did quite a bit of research into the speaker parts used in the stock system and confirmed that they are all 4 Ohm.

2: Yes the rheostats or impedance matching controls are how I control/set the impedance that the amplifier sees after connecting all of the speakers. As you are probably aware, these controls have an impedance multiplication switch on them that goes from 1x, 4x 8x and 16x. Since I have ~1 Ohm impedance in the front and approximately 2 in the rear I have it set to x8 multiplication in front at 4x in the rear effectively making the amps see 8 ohms respectively.

Regarding the tweeters: This was a concern of mine. I did a bit of research and found a post with pictures from total tear down of the sound system that someone had done to completely rewire their 2004. In that post the picture showed a high pass filter on the back of the tweeter. I also confirmed this by hooking up only the tweeters to ensure that no low frequencies were being passed in this set up.

Regarding the power delivery to the speakers, yes it does seem like they would be under powered but in reality there is ample volume without cranking it being delivered by the combination of the head unit and factory speakers. Perhaps the VW speakers have a high sensitivity rating?

3: I did bypass the factory amp. In fact I removed the harness that delivers the power to the speakers entirely from the factory amp and connected the wires from the black box into the corresponding speaker 'terminals' on the harness. There are a couple of terminals on the amp designated for line in that correspond to the line out on the harness up front. From what I was able to determine the factory head unit sends left and right Line Out to the factory amp and the necessary signalling to: turn on/off and control balance and fader via CANBUS. It may be possible to figure out how to emulate the CANBUS signal and then tap into the Line Out wires located off the front wiring harness and in fact from my understanding it appears that Canshack almost had this figured out except that their cable was ridiculously expensive and you could not control the fader (and balance?) with their solution.

My solution while not elegant certainly works the way I expected it to.
 

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Discussion Starter #14
Now that I am at my home computer I found the picture someone took of the tweeter removed from the front of a 2004 Touareg. As you can clearly see, the impedance is 4ohm and there is high pass filter connected to it.


Here's a link to the speaker sizes and impedance:2004 Touareg speaker sizes and measured impedances
 

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Looks like you really did your homework on this one, and a good job too.

It took me a while to figure out how your system is working but I'm understanding more now.

The biggest thing is you are using "Impedance matching volume controls" not rheostats for the control switches. These have audio transformers in them to convert the impedance without applying a resistive component that could possibly mess with the signal and drain the power you need from the head unit. That's a genius idea!

I did some checking and these transformers can be had for just a few dollars and mounted on a circuit board to make everything neat and all contained in a single box if one wanted. I'm all over doing that :). Using more specific transformers would also allow more refined matching to the head unit's impedance and power, (the lower 12V signals don't need the larger transformers that are found in home switches).

With the filters built onto the speakers that problem is no more. Even better if the subs and mid-range had some filtering too, (which they might).

Another question I had is why you selected the settings you did for a total of 8 Ohms? (Unless it was solely the limitation of the switch you were using). Usually car audio devices use 4 Ohms unless it's subs or a specially designed system (such as some Bose or JBL systems). I couldn't find the output specs of the head unit but would guess it's 4 Ohms. A 3x transformer and a 2x transformer would seem to come out much closer to this standard and resulting in much better performance since they head unit would not have to work so hard (but good that you would over shoot than not).

One last question, for now, did you calculate the center speaker into the system any where? The way you show it wired it would actually increase the impedance of the fronts and so you'd be even higher than the 8 ohms you were shooting for, (again better to be over than under but could be refined with more specific transformers).

You've really got me excited about this project. \\:D/
 

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No problem! To answer your questions:
Sound System II which is the CD based NAV is rated at 400 Watts for 11 speakers. By my math
that would mean that the factory amp is pushing roughly 35 watts per speaker. I don't know what the power ratings of the speakers are but I'd guess that Volkswagen would have added some buffer which means they should be able to handle 45-50 watts of clean power.
The 400 watts should be maximum value, not rated value.
Generally the amplifier power should be 1.5-2 times of car speakers' power.
And 60-200 watts is enough to power 11 car speakers. The power output depends on the volume size and frequency.

Does the new head unit have enough power? Your estimates for the speakers (~50W) are very low even for factory speakers and I would guess that these are probably not being driven with the amount of power they should. This won't be a problem till the volume knob gets turned up.3) Couldn't an amp out signal from the head unit be used as inputs to the factory digital amp? I'm guessing not since that would be too easy and someone would have done it by now.
The 50W is maximum value of the head unit's built-in amplifier can output(one channel). The power output depends on the volume size and frequency.

The reality is that most (if not all) head units are designed to handle a minimum impedance of 4 ohms. Any lower and you will overload the amp and damage it.
The head unit has 4(channel)*50w(watts) output. It only tell you the output of one channel is 50W, it does not matter what car speakers you will use, 2 ohms, 4 homs or 8 homs will be OK.

So the power should not be a problem.
Tone of speakers depends on frequency of electric current.That's what we known treble, mid and bass.
Volume of speakers depend on value of electric current.(I=U/R, in fact it is controlled by the voltage.) The bigger the better.

Let us go back to the impedance of speakers. P=U²/R
U, depends on the head unit's output.
R, the impedance of speakers.

So I have the same questions as @g500xl, do you really need to implement 2 impedance matching circuits. The more impedance matching circuits you use, the more watts will be wasted on them. And the bad audio quality you will get.

What my suggestion is that can you add a frequency divider on one channel. Then the treble, mid and bass speakers will work on their own area. The sound will be better.
 

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Couldn't an amp out signal from the head unit be used as inputs to the factory digital amp? I'm guessing not since that would be too easy and someone would have done it by now.
The original plug on your vehicle should have the three groups audio sources, see the wiring diagram.jpg photo below.



My thought is if the audio sources can accept the audio signal from head unit, then the factory amplifier should work as before.

The lower level audio output is on the RCA audio cable, if you can connect the RCA audio cable to the factory audio sources, this should work?



1. Modify a RCA adapter as shown in the photo. I modify it via a back up camera cable.


2. Connect the RCA audio cable to the head unit.
3. Connect the RCA adapter between the head unit and original plugs as per the wiring diagram.
4. Restore the original amplifier plug and see if there is audio from the car speakers.


Any thoughts?
 

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Discussion Starter #18
Looks like you really did your homework on this one, and a good job too.

It took me a while to figure out how your system is working but I'm understanding more now.

The biggest thing is you are using "Impedance matching volume controls" not rheostats for the control switches. These have audio transformers in them to convert the impedance without applying a resistive component that could possibly mess with the signal and drain the power you need from the head unit. That's a genius idea!

I did some checking and these transformers can be had for just a few dollars and mounted on a circuit board to make everything neat and all contained in a single box if one wanted. I'm all over doing that :). Using more specific transformers would also allow more refined matching to the head unit's impedance and power, (the lower 12V signals don't need the larger transformers that are found in home switches).

With the filters built onto the speakers that problem is no more. Even better if the subs and mid-range had some filtering too, (which they might).

Another question I had is why you selected the settings you did for a total of 8 Ohms? (Unless it was solely the limitation of the switch you were using). Usually car audio devices use 4 Ohms unless it's subs or a specially designed system (such as some Bose or JBL systems). I couldn't find the output specs of the head unit but would guess it's 4 Ohms. A 3x transformer and a 2x transformer would seem to come out much closer to this standard and resulting in much better performance since they head unit would not have to work so hard (but good that you would over shoot than not).

One last question, for now, did you calculate the center speaker into the system any where? The way you show it wired it would actually increase the impedance of the fronts and so you'd be even higher than the 8 ohms you were shooting for, (again better to be over than under but could be refined with more specific transformers).

You've really got me excited about this project. \\:D/
Yes, I used over the counter parts on purpose since they weren't all that expensive and allowed me to test my theory with the least amount of effort required.

I have no doubt that an all in one solution could be developed using the transformers mounted to a circuit board with the wires being distributed to the male harness that mated with the existing factory harness. Since there is plenty of room where the stock CD changer is you could build this box and replace the CD changer (which is right below the stock amp) and then you could have a plug and play solution. Going to and from stock would be a matter of swapping 3 harnesses between the front and rear of the vehicle. The biggest challenge I see is in the harness. I'm pretty sure that the harness used on the amp is proprietary so it may need to be fabricated.

For my impedance values, I chose to err on the high side as I didn't want to blow the amp in my new head unit. I've been running it for a few days now and I am extremely pleased with the sound. Definitely a huge upgrade over the stock system, even though I'm using the same speakers. With that said, there is a lot of room for improvement. The main thing is that it works. :)
 

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The head unit has 4(channel)*50w(watts) output. It only tell you the output of one channel is 50W,
50W RMS per channel should be fine for the system, I just didn't know that spec. so it's hard to guess on something you don't know. Thanks.

it does not matter what car speakers you will use, 2 ohms, 4 homs or 8 homs will be OK.
It does matter, at least to some extent, what the speakers impedance is. It should be matched as close to the head unit as possible. Though it's much less important for newer solid-state circuits, it can still make a big difference; if say your amp is 4 Ohms and you use two 4 Ohm speakers in parallel you have a 2 Ohm system. Attempting to drive this 2 Ohm system with a 4 Ohm amp will require excessive amounts of power (as compared to a 4 Ohm system) and could cause problems, more for the amp but also clipping in the speakers. This is why Mancubus aired to the safe side and bumped it up to 8 Ohms.

Let us go back to the impedance of speakers. P=U²/R
U, depends on the head unit's output.
R, the impedance of speakers.

So I have the same questions as @g500xl, do you really need to implement 2 impedance matching circuits. The more impedance matching circuits you use, the more watts will be wasted on them. And the bad audio quality you will get.
Using a transformer instead of a true "impedance matching circuit" (which usually contains resistors instead) doesn't waist much wattage in comparison. It does change the voltage level somewhat but keeping it at a consistent level it will not be noticed much.

What my suggestion is that can you add a frequency divider on one channel. Then the treble, mid and bass speakers will work on their own area. The sound will be better.
The filter on the tweeter actually already does this (and I wouldn't be surprised if someone looked there was one on the sub and/or the mid-range) so it's already taken care of.

... I am extremely pleased with the sound. Definitely a huge upgrade over the stock system, even though I'm using the same speakers. With that said, there is a lot of room for improvement. The main thing is that it works.
I've read somewhere on the forum that the speakers were good quality once driven by a different amp and used with some sort of sound conditioner. Very good to hear you think it's superior, I'm definitely going to have to do something similar.
 

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Discussion Starter #20
The original plug on your vehicle should have the three groups audio sources, see the wiring diagram.jpg photo below.



My thought is if the audio sources can accept the audio signal from head unit, then the factory amplifier should work as before.

The lower level audio output is on the RCA audio cable, if you can connect the RCA audio cable to the factory audio sources, this should work?



1. Modify a RCA adapter as shown in the photo. I modify it via a back up camera cable.


2. Connect the RCA audio cable to the head unit.
3. Connect the RCA adapter between the head unit and original plugs as per the wiring diagram.
4. Restore the original amplifier plug and see if there is audio from the car speakers.


Any thoughts?

Running the line out to the amp may work using the cables at the front but I believe that the amp on/off is controlled via CANBUS but I could be wrong.

Since my car is already put together and this is my daily driver, I won't be able to test the RCA output to the amp. Also, until we figure out how to turn the amp on it won't matter if we can get a signal to the rear, which I'm sure we can.
 
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