subterFUSE

Noise cancellation will not work well with an aftermarket processor. The BitOne needs to have a consistent signal fed into it or else it will affect the processing it is responsible for, and the signal-to-noise ratio.

Bose has tweaked and tuned the audio system to work with their speakers. In order to maximize the performance of aftermarket gear, I need to have a clean and stable signal from the OEM source. The BitOne actually provides a Setup Wizard with a Test CD that helps it to analyze the OEM system for any factory equalization, and then it counters that equalization to yield a flat signal. That flat signal is then processed by the BitOne's internal DSP in a much more advanced way.

If the OEM signal is being dynamically altered by a feature like the Bose AudioPilot, then the BitOne won't have the stable signal required for best performance.


During the installation of the system we will put many hours of labor into sound dampening the car. The combination of sound dampening plus the extra power being added (1950 Watts total) will negate the need for any active noise cancellation.

DeerHunter

Fair enough. Appreciate the detailed reply.

cvbmilani

Great research so far. I have a A6 C7 and want to upgrade the audio as well.

I am assuming you have not upgraded yet. If you have can you post the final solution?

Have you find out the solution for having the Bluetooth working? Are you just connecting the bitone to the high level amp outputs?

Can you share the bose wiring diagrams that you mentioned?

Thanks

Delurker

I'm looking forward to finding out as well - I'd rather not lose bluetooth even though I only use it for infrequent calls in the car, and I'm hoping that what comes out of the bitone is a good enough signal that it sounds a whole lot better than the stock Bose junk when played through better amps & speakers.

subterFUSE

We have not yet begun the installation. At this point, I am awaiting some equipment that is on backorder and a more detailed response from tech support at MoBridge.

As it turns out, there are 7 microphones inside the A6/S6. 4 of those mics are for the Bose AudioPilot noise cancellation. The other 3 are for bluetooth and voice recognition.

The 4 Bose mics all connect to the Bose amplifier.

2 of the 3 bluetooth mics connect to the Information Elec Control Module.

1 of the 3 bluetooth mics connects to the Bose amp.



The MoBridge works by intercepting the MOST bus digital signal before it reaches the factory amplifier. Therefore, anything that connects directly to the factory amp would be bypassed.
Since one of the bluetooth mics is connected to the Bose amp, I need to confirm what effect this would have on the performance of the bluetooth if the MoBridge were used.

Their tech support is working on this answer for me, and said they would get back to me in a couple of weeks.

I feel like a bonehead for not seeing this sooner, but it turns out the Bose AudioPilot can be disabled in the MMI software. So I don't think there is a need to disconnect the AudioPilot microphones after all.




If I can use the MoBridge, then that would be great.
If not, then I will go with the BitOne connected to the Bose amplifier via speaker connections.

The BitOne has 8 inputs available.

The Bose amp has 12 outputs.


I would use the following outputs from the Bose amp if I choose to connect to the BitOne:

Front Tweeter Left
Front Tweeter Right
Front Midrange Left
Front Midrange Right
Front Woofer Left
Front Woofer Right
Subwoofer
Center Channel


The following Bose outputs would not be connected:

Rear Left
Rear Right
Left Surround
Right Surround


I have been told by two sources that the parking sensors have their own tone generators that work independently from the stereo. This is great because I am not going to have enough inputs on the BitOne to connect the rear speaker outputs from the Bose. On my old BMW, the parking beeps worked through the stereo so I had to keep the rears connected to the BitOne or else I lost the beep sounds. This is not so with my Audi, if what I've been told is correct.


I spent some time talking with tech support at JL Audio about recommendations for my subwoofer. We have tentatively come to the conclusion that I should do a single JL Audio 12W7 woofer in a sealed enclosure. My Audison Voce AV5.1k amplifier has a subwoofer channel that is 1000 Watts @ 2 ohms. The 12W7 subwoofer is a 3 ohm speaker. So we are guessing my amp would drive about 750-800 Watts @ 3 ohms. 750 Watts is the recommended power for the 12W7, so they should be a perfect match.


My proposed system design should look like this:

MoBridge DA1 (if possible)
Audison BitOne
Audison Voce AV 5.1k amp (5 channel)
Audison Voce AV Due amp (2 channel)
Hertz Mille System MLK3 3-way component speakers
JL Audio 12W7 subwoofer, sealed enclosure


The Hertz Mille speakers would be installed in the factory locations. Tweeters go in the dash at the corners of the windshield/pillars. Midrange and midbass in the front door locations.

75 watts x 2 tweeter
140 watts x 2 midrange
260 watts x 2 midbass
~800 watts x 1 subwoofer

~1750 watts total


To install the amps we will do the same setup as with my BMW previously. They will fabricate a metal frame that will screw in to the underside of the rear shelf inside the trunk. This will only create 4 points for screw holes in the car frame. The BitOne and 2 Audison amps will mount to the frame so that we minimize the number of screws into the car itself. The Audison amps are internally fan-cooled so they won't overheat when mounted upside down.

The Audi battery is conveniently located in the tire well, which makes life very easy for running power to the amps and DSP unit. The only wires that will need to be run to the front of the car are speaker cables for the Hertz components, and the DRC control cable for the BitOne.

I believe we will put the BitOne DRC inside the storage compartment below the A/C controls, although we have not discussed that part yet.

The JL Audio subwoofer will simply be a wood box with carpet to match the trunk interior. We will have a latch or bracket to hold it in place, while still allowing for easy removal if I need the extra trunk space for a trip.

subterFUSE

In my BMW I ran the BitOne directly from the Logic7 amplifier. The sound quality is excellent, so don't worry about that.
The BitOne comes with a setup CD that you run in the dash CD player while the BitOne is connected to a PC. The PC software reads test signals from the setup CD and makes adjustments to any factory equalization that may exist in the Bose system. This ensures a clean, flat source signal is presented to the BitOne.


If you want even better sound quality from your iPod, you can buy an iStreamer 12V for about $200. The iStreamer is an outboard DA converter for iDevices. It bypasses the iPod internal DAC and uses an outboard 24 bit DAC that is jitter-free.
The only downside is that you will have to connect this to the BitOne via an AUX input. That means you will have to switch the BitOne to the AUX channel to listen to it, which would mute the MMI system sounds until you switch back to Master.

dy_TX

Hi subter, thank you for chronicling this build as I am currently planning a very similar one for my 2014 Audi that is being built right now, set to arrive later in October. I have a couple comments and a couple questions.

First, I love the choices of the Audison Voce, BitOne and JL W7 sub.

I used to have a JL 10w7 in their sealed enclosure, powered by a JL 500x1 amplifier in my last car and it was mind blowing how powerful and accurate it was. Additionally, I currently run their Fathom f112 in my home theater and again, just in a class of its own. My only comment for your build is that you if you were on the fence of whether the 10w7 was going to be enough for your setup and decided that you might do the 12 instead.. I can tell you first hand that you will not get the 10w7 and think 'man i really wish my sub hit harder or had more output'. The depth, power, and accuracy of the 10w7 was just incredible and I never felt like I wanted the 12, even for as much of a bass junkie as I am. Having said this, I know the 12 will be incredible as well if you go that route.

Additionally, just to add to your confidence regarding the mobridge, I called their Australia team a few weeks back and got the same scoop regarding the developers having tested it on the 2013 and 2014 3g MMI systems and it working fine, besides the issues you mentioned, so hopefully that will all work well.

One question I had for you is around your decision to utilize the high-level outputs from the stock amplifier vs bypassing it completely, in favor of preserving bluetooth. I have been pondering this one also and currently do not use bluetooth in my car (though perhaps I would want to in this new one). It just seems to me with a setup this great, that you would want to skip the garbage Bose (or B&O in my case) amplifier at all costs in favor of digital all the way?

The second question, which I've never been able to get a clear technical understanding of for both home audio as well as car audio is regarding DAC. If you went digital all the way, using the mobridge and digital all the way to the Voce's, then would it make a sound quality difference if you utilized the Audi iPhone digital connection, Bluetooth audio from iPhone, or connected a standalone digital connection to the iPhone direct from the BitOne? Since the DAC is being done at the Voce in this scenario, I would assume that it would make no difference how the audio was being streamed digitally to the Voce.. Correct? This is the same question that arises in my mind when I have my home theater receiver doing the DAC for audio coming from my iPhone and I compare the methods of fibre optic from my home iTunes vs playing from AppleTV (HDMI to receiver) vs AirPlay from iPhone to AppleTV vs AirPlay from iPhone to receiver directly... This relates to my first question, as bluetooth streaming of audio to the car's head unit is a very convenient way to access audio, but obviously we would want the highest quality playback possible.

Sorry for the long post!

cvbmilani

Thanks subterFUSE for the reply.

I am planning to go with the bitone because my MS-8 is a hiss generator machine (let me know if you are in need of one).

When you were running the bitone directly from the logic7 did you experience hiss?

dy_TX: As far as my research on Bluetooth audio went, although it is digital, Bluetooth audio A2DP does not have the same bandwidth (aka bitrate) as other digital protocols, such HDMI, and therefore the resolution is lower. So depending on the source audio stream there will be digital resampling. Unfortunately it is not a standard and depends on the handshake between audi MMI and iphone. it could be 200kbps, maybe 320 or more.

dy_TX

cvbmilani: Thanks for the info on the Bluetooth streaming. That was my suspicion, as I have had some perceived quality degradation in my friends' cars that use it. I guess this is another vote towards why I will potentially forego Bluetooth in favor of the MoBridge digital approach.

subterFUSE

Good information. I have used JL Audio subwoofers in every car owned since 1997. My typical setup was always three 10W6 subs in custom, sealed enclosures. My preference is for very tight/accurate bass but with good impact.

When I built the system for my 2005 BMW 545i, I decided that I did not want to lose very much trunk space. JL Audio had a Stealthbox enclosure for the E60 so I went with that. It was a single 12W6 sub in a fiberglass sealed box that only took up the corner cubby on the side. The sound quality was good, but it was a lot less bass than I was accustomed to.

For my Audi, I want to have more bass than the BMW, but I am a little bit restricted because I already have the amplifier that will run the subwoofer(s). The Voce AV 5.1k has a mono subwoofer channel that does 600W @ 4 ohm, or 1000W @ 2 ohm.

The JL Audio W6v3 series subs come in dual 4 ohm voice coils. They can be wired 8 ohm or 2 ohm. If I used two 10W6 subs, then I would have to wire them each as 8 ohm, then together in parrallel which would result in 4 ohm to the amp. That's 600 Watts for two 10's. It will work, but it's a little bit below JL Audio's recommended power for those subs.

The 10w7 & 12w7 subs are 3 ohm speakers. So I could run a single 10 or single 12 and get about 800 Watts out of the Audison amp. I could not do two 10w7 or 12w7 because the 1.5 ohm impedance would be too low for the Audison.

Or I could do a single 13w7. Those are dual 1.5 ohm voice coil, so it could be wired @ 3ohms.

After posing those options to a tech at JL Audio, he suggested I do a single 12w7. He felt that it would be better than two 10W6 subs because I would get more power out of my amp @ 3 ohms vs. 4 ohms. The 800 Watts @ 3 ohms is perfect for running a 12w7.

I may still consider a 10w7 at your suggestion, however. Maybe we will test out a 10 first and then try the 12?


In theory, yes it would be better to use the MoBridge and keep the signal digital. If I can confirm the MoBridge works 100% with my car and preserves the bluetooth, then I will go that route.

However, I have already used the BitOne with success via speaker-level inputs in my BMW. The BitOne was originally designed to work this way, and it works well.


The answer is yes. It does make a difference how you connect your iPod or other sources, regardless if you have the MoBridge or not. While the MOST signal is digital, the original source music must get transferred from the media device to the Audi first. Depending on the source, that process may involve D/A conversion or A/D conversion. Snagitseven has posted pretty extensively on the topic of audio sources and conversion. You can search for his detailed explanation on sources and conversions.


Speaking just to the use of an iPod or iPhone:


iPod/iPhone via AMI cable

The AMI cable does not bypass the Apple internal D/A converter, so the signal gets converted to analog and then converted back to digital before being transmitted via the MOST bus to the factory amp.

Advantage: All file formats supported by Apple are available. WAV, AIFF, MP3, AAC, Apple Lossless. Full iPod control via MMI. Artwork. Gapless playback supported. Browse by Composer supported. (huge feature for me)

Disadvantage: Conversion from Digital to analog and then back occurs. Some quality will be lost.


Bluetooth

With Bluetooth you get some control over the iPhone/iPod, but not the full control like the AMI gets. I do not know the stats on the quality of the bluetooth audio stream, but my gut tells me it is probably lower quality than the AMI cable connection.

Of those two options, I would personally use the AMI cable.




With the Audison BitOne you will also have the option to connect audio sources directly to the BitOne. The BitOne has an Optical Digital input, a SPDIF digital input, and 2 sets of RCA analog inputs. In addition, the BitOne has very good 24 bit Wolfson D/A converters.

In my BMW, I chose to add a small device called the iStreamer 12V. The iStreamer is basically an outboard D/A Converter for iPods. It bypasses the iPod internal DAC, and then converts the signal with its own DAC that is much better. You get a clean, analog RCA output with no jitter. I ran that directly into the BitOne and the sound quality was excellent.

One more option I had on my BMW was to run an iPad with an optical digital output directly into the optical input on the BitOne. The sound quality was great, but the one drawback was that this required the iPad be connected to the USB camera adapter to work. That meant I could not charge the iPad while listening. Of course, there was also the sheer inconvenience of having an iPad up front.

I found that the difference in sound quality of the iStreamer vs. the iPad optical digital connection was not noticeable. Plus, the iStreamer could charge the device while connected.
Convenience won out in that battle.


The only other downside to directly connecting the iPod to the BitOne was that it required the BitOne switch sources from Master to AUX. Master was the connection to the factory stereo. That meant all of the car's audio was muted while playing the iPod. Not the end of the world, but if you were running navigation you would lose the audio prompts. And if someone called me on the phone I had to switch to Master to get the bluetooth audio for the phone.


Lastly, Audison is developing a digital media player for the car which they call the BitPlay HD. It will be 24 bit 192k capable, compatible with FLAC, WAV, AIFF, and other lossless formats. 250 GB hard drive, I think. Will plug directly into the BitOne and give you completely digital signal with no conversions from source to amplifier.