Coding 2015 S model for line level out

[calico031]

I've tried searching for this for quite some time so forgive me if I missed it elsewhere but I'm wondering if anyone ever figured out how to code our radios to output line level like you could in previous MK models. Specifically the 2015 base model S without fender audio. I'm thinking it should be possible because of the available helix sound system add-on. Or if anyone knows if it's possible to disable the bass loudness function, that would help as well. I'm using OBDeleven if it matters.

Chris

 

[MiamiBourne]

I've tried searching for this for quite some time so forgive me if I missed it elsewhere but I'm wondering if anyone ever figured out how to code our radios to output line level like you could in previous MK models. Specifically the 2015 base model S without fender audio. I'm thinking it should be possible because of the available helix sound system add-on. Or if anyone knows if it's possible to disable the bass loudness function, that would help as well. I'm using OBDeleven if it matters.

Chris

Would something like this eliminate the need for an LOC like the LC2i which restores the bass? If so then I would like to know as well! I heard of this being able to be set with older platforms with VCDS also.

 

[calico031]

Yup, would be a low level signal so no need for a LOC. Should also be free of any factory EQ so perfect for running directly to a processor or amp. The LC2i's bass restoration capability would be unnecessary since the bass would never be filtered out to begin with.

 

[beardedGTI]

I'm not sure I would count on it being a completely flat signal. Yes I know that would be ideal, but the signal is still be routed through the same amp path, simply at a lower level. You'd have to count on the flag also telling the dsp earlier on in the chain to not do anything to the signal. Coming from Honda, they do this and it's annoying. Line level can be tapped before the factory amp, but dsp adjustments are still intact.

 

[calico031]

I'm not sure I would count on it being a completely flat signal. Yes I know that would be ideal, but the signal is still be routed through the same amp path, simply at a lower level. You'd have to count on the flag also telling the dsp earlier on in the chain to not do anything to the signal. Coming from Honda, they do this and it's annoying. Line level can be tapped before the factory amp, but dsp adjustments are still intact.

I'm assuming it's flatter based on the way the helix add-on unit works. When things are stock, the high level signal is high passed at 40 Hz to protect the stock speakers as well as the fact there's no sub to handle lows. The helix unit adds a sub and has its own DSP so I'm willing to bet that when it's coded correctly, an unfiltered signal is passed to the helix DSP and any equalization is done in the DSP and not beforehand in the head unit. There's also been a precedent set with previous models where coding does in fact create a relatively flat signal. You can't really compare what Honda may do to what VW does as they have nothing to do with each other. But at the end of the day there's only one way to know for sure.

 

[flipflp]

Some things I've read that might support your belief on the helix system, I've read a few installs so far and because it requires a wiring harness that goes to and from the DSP unit, as well as a dongle to code the system by car, it would make sense that the DSP gets a relatively flat signal and does whatever with it that car is spec'd to have. That also includes some balancing if I'm not mistaken.

Sadly it will never be a true "line" out, but a flat high level is better than nothing.

Then again you might just be complicating things when a LC2i works pretty damn well for sub-$100.

 

[beardedGTI]

I'm assuming it's flatter based on the way the helix add-on unit works. When things are stock, the high level signal is high passed at 40 Hz to protect the stock speakers as well as the fact there's no sub to handle lows. The helix unit adds a sub and has its own DSP so I'm willing to bet that when it's coded correctly, an unfiltered signal is passed to the helix DSP and any equalization is done in the DSP and not beforehand in the head unit.

I have a helix system. As far as connection goes, it simply intercepts the speaker level outs, nothing else. Nothing at the DSP level in the head unit changes.

 

[copperbricks]

I was just wondering this as well. So the dongle included with the helix doesn't result in a subwoofer specific out? Are you sure that there's not some extra pin the Helix taps into or something?

Also with regards to the LC2i, will that produce different/better results than simply using an amplifier that has speaker level inputs and a crossover?

 

[beardedGTI]

I was just wondering this as well. So the dongle included with the helix doesn't result in a subwoofer specific out? Are you sure that there's not some extra pin the Helix taps into or something?

I just want to quickly clarify for anyone looking to purchase the helix system, the dongle is not included. You have to buy/rent it separately. But all that the dongle does is load the profile for the DSP in the helix box that is specific to your car.

The helix box is nothing more than a Match PP52DSP in a custom box. It has 2 inputs for power, then 8 inputs(pins) for the 4 channel audio that it grabs from the HU speaker output, then 8 outputs that go back into the factory speaker harness, then 8 more outputs that go to the 2 DVC subs in the box. There are no pins for serial communication anywhere. The HU has no idea the helix system is present. It's getting the full speaker level non-flat output from the HU.

Also with regards to the LC2i, will that produce different/better results than simply using an amplifier that has speaker level inputs and a crossover?

The problem here is how you want to qualify "better". Ideally you want a flat non-eq signal going into your amp. This is what the LC2i will provide. Sending the speaker level inputs straight into your amp will still have eq from the HU no matter how you adjust the crossovers on the amp. Will this sound "worse" without first flattening them with an LC2i? ¯\_(ツ)_/¯ Sound quality is a highly subjective thing. If you're primary goal is to get more bass, you may not be getting as much as you could without first flattening the signal due to roll off from HU signal.

To me, the helix box is a hell of a deal for what it costs vs what it provides. If you don't agree and want a more custom solution that is similar, you may want to look into something like the PP52DSP or if you can find a used one, the JBL MS-8. They're the same thing as the Helix, you just have to bring your own speakers/sub and do the setup of the cabin correction yourself which is not a trivial thing. If you don't care about acoustic correction (which you should definitely listen to with your own ears before making that call), then an LC2i + amp will suffice.

 

[copperbricks]

I think i'll probably set up my system without an LC2i and order one if I feel like I need it. The other stuff you linked is interesting, but looks a bit complicated for me. Thanks for the info though!

 

[flipflp]

Ah the more I thought about it and after I watched the install video for the Helix it makes sense, you aren't recoding the HU output, you're just sending high level outs through the DSP box, which I'm assuming adds back bass (and then immediately removes and routes to the sub), and through the dongle will properly code for cabin size, etc. Very very cool setup for the helix indeed. At $5-600 not a bad price either, considering what you'd be in for with an LC2i, wiring, amp, sub, box, etc.

With an LC2i setup, I would have a hard time not amping at least the front speakers as well, with a 5-channel/3-channel amp to cover them and the sub. Is the helix system amp ONLY for the subs or does it re-up the other speakers as well? Might not be a huge factor but if you're going to dive in why not do it into the deep end, right?

 

[beardedGTI]

Helix is an amp for all speakers.

 

[flipflp]

Helix is an amp for all speakers.

Well damn. Considering its OEM and doesn't mess with cargo space I'm pretty much sold on that. Thanks for the info!

 

[beardedGTI]

Well damn. Considering its OEM and doesn't mess with cargo space I'm pretty much sold on that. Thanks for the info!

Overall I'm happy. Dealer charged me $550 + tax (I had to do the install myself) and I'm about to submit a rebate for 15% back. To be clear, I think the performance for what it cost is totally there. You get slight bump in power, plus a sub, plus a factory set DSP which really increases the overall sound quality and it's easier to install than a custom setup. It's not as a good as a similar $1-2k setup with separate components that's been tuned by a pro nor does it give you thumping bass. You also loose your spare tire. There's pro's and con's to be weighed so it may not be for everyone.

 

[flipflp]

Overall I'm happy. Dealer charged me $550 + tax (I had to do the install myself) and I'm about to submit a rebate for 15% back. To be clear, I think the performance for what it cost is totally there. You get slight bump in power, plus a sub, plus a factory set DSP which really increases the overall sound quality and it's easier to install than a custom setup. It's not as a good as a similar $1-2k setup with separate components that's been tuned by a pro nor does it give you thumping bass. You also loose your spare tire. There's pro's and con's to be weighed so it may not be for everyone.

All the pro points there for sure. For me in a Golf R I don't lose what I never had so there is really no "con" for R owners regarding a spare tire.

I've been a car audio enthusiast for a long time, but I've been out of the game so long that it's been hard for me to relearn enough to feel comfortable piecing together components for an install. This really seems like the answer for someone that values quality but doesn't need to set off car alarms or invest too much money/time.

A bit of a OT spot there, but hopefully the Helix conversation helps out the OP