# Audi TT MK3 remote / audio line out for subwoofer



## JohnTT2016 (Sep 17, 2018)

Hi All,

Does anyone have information / photos on obtaining a line level audio feed from the MMI to feed a small active subwoofer? And if possible a remote to switch the subwoofer on etc,

I could use a high level input from the rear speakers if the above is not possible how easy are these to access and does anyone have any photo's showing removal etc,

My TT has the 'upgraded' audi sound system with the small 5 channel amp i believe i have no idea where this is either,

Appreciate any help!

Cheers!

John


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## GavinE (Aug 21, 2016)

JohnTT2016 said:


> Hi All,
> 
> Does anyone have information / photos on obtaining a line level audio feed from the MMI to feed a small active subwoofer? And if possible a remote to switch the subwoofer on etc,
> 
> ...


Looked into this myself about a year ago.

The Amp is somewhere hidden under the drivers seat.
I am informed it is fed via a digital cable from the MMI. The standard speaker outputs from the MMI are not used so the high level feed would need to come from the Amp and not the loom in the back of the MMI unit.

I am also advised there is no line out or remote trigger. I stopped at that point.


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## macaddict111 (Jun 13, 2018)

The question is, do you have B&O? If you do, the amp is under the driver's seat fed by a fiber-optic cable from the infotainment controller in the glove box. If you don't (regardless of "base" or "middle" sound [difference is simply less speakers installed on base]), the amp is integrated in said glove-box infotainment unit with nothing under driver's.

I have B&O and I'm tempted to do this myself eventually, and frankly my best idea is to splice into the high-level rear speaker wires, since they're close to the trunk and that's about all you can do. The problem is, this is probably a fairly poor place to get "raw" bass to amplify, as the B&O is very calibrated for the particular speakers they used, and also the rear's are fed processed audio from the "Sound Effects", which is actually the Logic algorithm (which is very good btw) creating 5.1 spatial audio out of stereo. I have a feeling the B&O system (maybe all of them) is doing a high-pass on the rear "bass" speakers since they're so small, and very low frequencies would probably just distort them.

Regardless, you are simply not going to find a good source or "raw" or low-level audio.


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## phazer (Apr 2, 2018)

Is it possible to add the subwoofer to the B&O system in the TT? It has a sub in the S3 and the MMI has a separate sub control alongside bass and treble. I'd be tempted as the sub unit is easy to chuck in and I would assume a bit of coding to enable the sub option.


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## macaddict111 (Jun 13, 2018)

phazer said:


> Is it possible to add the subwoofer to the B&O system in the TT? It has a sub in the S3 and the MMI has a separate sub control alongside bass and treble. I'd be tempted as the sub unit is easy to chuck in and I would assume a bit of coding to enable the sub option.


Oh wow I didn't realize that. Does is have the amp embedded in the sub unit? Because it would probably be nearly impossible to retrofit the under-seat hardware. You're making me wish I'd downloaded an S3 wiring diagram to see how the sub is being fed (low or high level from B&O amp).

The software/MMI implications would probably be a nightmare, not to mention cost of getting an Audi replacement part vs aftermarket sub. That's vs basically the time and effort of removing the rear passenger's side panel to get at the speaker back there, and risk it would have a high-passed/otherwise poor signal for driving aftermarket amp. Sounds like others have had success.


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## ZephyR2 (Feb 20, 2013)

Not sure how similar the S/A3 is to the TT as they have a sub in the boot with their B&O and ASS. Nevertheless you might find these threads on the A3 Audi-Sport site of some help ....
https://www.audi-sport.net/xf/threa...fsen-sub-to-the-standard-sound-system.245596/
https://www.audi-sport.net/xf/threads/has-anyone-added-a-subwoofer-or-amplifier-to-their-8v.373961/


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## phazer (Apr 2, 2018)

ZephyR2 said:


> Not sure how similar the S/A3 is to the TT as they have a sub in the boot with their B&O and ASS. Nevertheless you might find these threads on the A3 Audi-Sport site of some help ....
> https://www.audi-sport.net/xf/threa...fsen-sub-to-the-standard-sound-system.245596/
> https://www.audi-sport.net/xf/threads/has-anyone-added-a-subwoofer-or-amplifier-to-their-8v.373961/


Cheers for the links. The TT is a rebodied S3 essentially, the kit is the same so would expect the MMI gear to be almost if not identical.


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## macaddict111 (Jun 13, 2018)

ZephyR2 said:


> Not sure how similar the S/A3 is to the TT as they have a sub in the boot with their B&O and ASS. Nevertheless you might find these threads on the A3 Audi-Sport site of some help ....
> https://www.audi-sport.net/xf/threa...fsen-sub-to-the-standard-sound-system.245596/
> https://www.audi-sport.net/xf/threads/has-anyone-added-a-subwoofer-or-amplifier-to-their-8v.373961/


Wow! Although it sounds like he had the middle Audi Sound System, not B&O. That he was able to use the sub that fits into the spare wheel speaks to me (I'd just remove my emergency kit and put it all in a bag). The fact that he had to take his whole dash apart is ewwwwwww.


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## macaddict111 (Jun 13, 2018)

Here's the problem I'm beginning to realize about adding a sub to B&O: there simply isn't anywhere to get 0-60 Hz audio except for skimming the fiber-optic MOST bus coming into the B&O amp. All of the channels coming out of B&O are high-passed, I absolutely guarantee it. Certainly the ones going to the small rear woofers, and I bet the signals going to front door woofers too. This is a GOOD thing normally, as trying to drive a small woofer with sub frequencies (0-60 Hz) is pointless. It can't make that sound anyway, so it just adds amplification heat and distortion. For B&O, it doesn't look like there's a dormant Sub output we could code on and get audio from (unless someone knows of one, which I'd love to know about). The only audio I can reasonably-easily get to is the high-level coming to the rear woofers, and this is high-passed.

I'm an electrical engineer, and I'm honestly going to start looking into what it would take to skim off the MOST bus. This is the only source of low-freq audio I think we're going to find. It's a fairly standard protocol with uncompressed, channeled audio. If I could patch into the fiber-optic connector and get a PCM stereo audio stream out of the signal going into the B&O box, that might be the only way to do it.

Question: does anybody know of the base/ASS amps are still in the basic headunit if the B&O amp is equipped? Could these be turned on at the same time as B&O so I get the sub signal that would have gone to the S3 AAS sub?


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## JohnTT2016 (Sep 17, 2018)

Hi Guys,

It's not the B&O system it's the upgraded Audi sound system extra £270 with a centre speaker in the dash and a small 100 watt 5 channel amp (somewhere)

If it was B&O I would probably leave it being honest.

Thanks!

John


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## ZephyR2 (Feb 20, 2013)

The speaker layout, details and location of the amp for the Audi Sound System has been a much debated mystery on here in the past. There's virtually no detailed information available.
Eventually I think someone found some useful info - well over a year ago. A search might throw up those findings.
Incidentally the ASS uses a 5-channel amplifier with a total output of 155 watts.


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## macaddict111 (Jun 13, 2018)

JohnTT2016 said:


> If it was B&O I would probably leave it being honest


Yup. There's guys who have done it on here tapped into the rear speaker. Like... Glad you're happy but you're not getting actual sub frequencies.


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## GavinE (Aug 21, 2016)

There's actually 4 systems which is what seems to cause the confusion.

Standard - 4 speakers
Tech Pack - 8 speakers
ASS - 9 speakers
B&O

The standard and Tech pack have no amp, the ASS and B&O do.

I believe the ASS is standard fit in the TTs


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## JohnTT2016 (Sep 17, 2018)

Hi Guys

The Audio 9 speaker system is an option it's still on the Audi configurator now, I've searched all the forums I can find for details of the amp and obtaining line out, because of this I was pretty sure I would need to tap into the rear speakers and run a high input into the amp, I've also found an amp with auto on so I do not need a remote either but as people have mentioned there is probably a active crossover removing the lower sub frequencies from reaching the rear speakers 

Does anyone have pictures of getting access to the rear speakers / wires etc as I don't want to damage any of the panels etc.

Thanks!

John


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## ckean_ng (Sep 21, 2018)

Hi Remove your mib2 unit and check into quadlock connector. There is a pin for subwoofer output. I not sure whether our mib2 need to activate by coding in order to get subwoofer signal. I refer this on VW mib2 unit from other forum today. Hope this help. Myself looking for adding subwoofer to my 9 speaker system TT techpack too.


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## Harsha369 (Sep 18, 2018)

ckean_ng said:


> Hi Remove your mib2 unit and check into quadlock connector. There is a pin for subwoofer output. I not sure whether our mib2 need to activate by coding in order to get subwoofer signal. I refer this on VW mib2 unit from other forum today. Hope this help. Myself looking for adding subwoofer to my 9 speaker system TT techpack too.


Any luck adding a subwoofer to your TT? I have the same tech pack 9 speaker system and I was contemplating adding one too!


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## daddow (Jan 1, 2017)

Can I ask you guys how long do you intend to keep your cars after these and other upgrades?, this has always intrigued me.


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## Harsha369 (Sep 18, 2018)

My car is around 2 years old will probably keep it for around for another 2-3 years.


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## Neeley1 (Feb 28, 2015)

macaddict111 said:


> Here's the problem I'm beginning to realize about adding a sub to B&O: there simply isn't anywhere to get 0-60 Hz audio except for skimming the fiber-optic MOST bus coming into the B&O amp. All of the channels coming out of B&O are high-passed, I absolutely guarantee it. Certainly the ones going to the small rear woofers, and I bet the signals going to front door woofers too. This is a GOOD thing normally, as trying to drive a small woofer with sub frequencies (0-60 Hz) is pointless. It can't make that sound anyway, so it just adds amplification heat and distortion. For B&O, it doesn't look like there's a dormant Sub output we could code on and get audio from (unless someone knows of one, which I'd love to know about). The only audio I can reasonably-easily get to is the high-level coming to the rear woofers, and this is high-passed.
> 
> I'm an electrical engineer, and I'm honestly going to start looking into what it would take to skim off the MOST bus. This is the only source of low-freq audio I think we're going to find. It's a fairly standard protocol with uncompressed, channeled audio. If I could patch into the fiber-optic connector and get a PCM stereo audio stream out of the signal going into the B&O box, that might be the only way to do it.
> 
> Question: does anybody know of the base/ASS amps are still in the basic headunit if the B&O amp is equipped? Could these be turned on at the same time as B&O so I get the sub signal that would have gone to the S3 AAS sub?


Im sorry to bump this thread (please delete if necessary) but i thought it may be of some help. You can join into a stereo pair of cables from the amplifier going to the front bass drivers on the B&O system. If you play test tones you'll find they reach down to 30hz. You can then connect the stereo pair to a hi / low converter or sub amp if it takes hi level inputs.


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## salvadore (18 d ago)

I know its super old thread, I give up with sub if I had to dig into amp under seat etc. What if subwoofer take bluetooth signal from smartphone, which send signal simultaneously to 2 devices (car player and subwoofer) at least my phone can broadcast signal to 2 devices in same time.


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## shtu (Nov 23, 2020)

Even if it technically worked, odds are you would end up with weird effects due to the two different audio devices not being perfectly synchronised. Bluetooth is not good for time-critical audio.

It would also mean every other audio input wouldn't have a subwoofer, which is likely to grate fairly quickly.

It's 15 minutes' work to access the B&O amplifier, and unless you're going to get DEEPLY involved, the simplest approach is to add a small underseat sub and tap the speaker outputs. Easy B+O Subwoofer Install How-To w/ Photos +Signal Analysis


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