Apple Carplay vs Bluetooth audio

I just purchased a 2019 GTI Rabbit and upgraded the audio with a Helix sub-woofer system. To make a long story short I wasn't too happy with the sound quality before the install and was somewhat disappointed with the sound quality after. It sounds flat, the soundstage seems muffled and at lower volumes (>25%) the bass is barely noticeable. Even when I turn up the volume, I have to set it to 40%+ to achieve any bass but at that point the mids and highs sound harsh.

Since I purchased the car I've only been using Apple Carplay and Spotify (a big selling point for me since I have a long commute to work). Today I decided to try connecting my phone using Bluetooth audio and the sound is night and day. The audio is richer, the mids and bass are fuller even at lower volumes, overall it's just clearer. I was so shocked at the difference I tested the same songs using Spotify confirming that there is a glaring difference in audio quality between Bluetooth and Apple Carplay (with Carplay having the inferior sound). My wife even confirmed the difference and agreed that the Bluetooth audio source is better.

At this point, I'm not sure what to do. I assumed that using a direct USB connection using Apple Carplay would be the superior sound source but that doesn't seem to be the case with my vehicle. (I also tested two aftermarket lighting cables and one Apple cable) Has anyone else run into this problem with their GTI? I found other people who have had similar experiences on other vehicles but none specifically on the GTI. Is this an issue with the 2019 model year?

For a bit more background, I haven't coded the Helix subwoofer yet but I can't imagine that's a factor in this case since I wasn't happy with the Apple CarPlay sound before I installed the Helix.

That sounds totally whack. No reason that you shouldn't get equal or slightly better (if you could detect it) sound quality out of your CarPlay connection than from a compressed Bluetooth stream. Playing anything via CarPlay in my '16 R sounds virtually identical to playing the same music from my SD card library, as it should. Your hardware is completely different though, being that somewhat different setup that comes on the S & Rabbit. I would try going back to the dealer and trying it on another car or two, even though they won't have the Helix sub, you could at least see if the sound is equal between inputs or not. Good luck in finding some sort of solution.

Did you program the helix after install? That will make a big difference in sound. It's night and day

Assuming you did, there is a setting for Bluetooth audio where you can select "loud" or something to that effect. That may explain the difference you heard. Before retro-fitting MIB 2 I was using that setting when listening over Bluetooth from my Android phone.

The Android Bluetooth stack uses an EQ boost when set above ~65% volume that introduces distortion. Listening from my wife's iPhone the "loud" setting wasn't necessary for decent volume.

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I just did a quick comparison on my 2019 and noticed the BT is definitely louder when I switch but didn't notice any difference in sound quality. What does coding the Helix do?

The Helix has to be coded to the vehicle it's in. More important than the amplification the Helix is a DSP. It can be installed in a variety of VW vehicles. Having it programmed correctly means it is tuned for the right vehicle size, speakers and speaker location. The programming is done through a dongle that you can buy from VW.

The other option is to rent it here on the forum. If you search for Helix Dongle there are a couple forum members that purchased one and they rent them out for a small fee, under $20 as I recall. You only need it once but the Helix is not programmed out of the box.

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Thanks everyone for the feedback. Good to know others detected the difference in volume between Bluetooth and CarPlay. I haven't coded the Helix system yet so maybe that will make a difference? I just can't get over how much better the Bluetooth connection sounds even without the coding.

Still doesn't seem right that I have to turn the volume to over 40% just to match the Bluetooth and radio connection at 15-20%. I need to go back to the dealer to get a few other things ironed out so perhaps I'll ask them to listen to another 2019 on the lot.

For what it's worth, I've yet to have my stereo at 50% since installing the Helix. Maybe check these in the volume settings (assuming they haven't changed the menu structure too much in the 2019s). I can't say whether Aux volume includes app-connect or only affects the 3.5mm jack but if Bluetooth is set to Loud that explains your volume discrepancy. And get that Helix programmed. Even if bluetooth is still louder it will make every source sound better. Except maybe FM radio, where it tends to highlight how bad the quality can be, haha.

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I didn't think to look in the volume settings. I'll try adjusting the Bluetooth to see if that makes a difference. I'm currently on a waiting list to rent the programming dongle for the Helix system so I'll have to wait to see what difference that makes (fingers crossed).

So I did notice the volume I have in carplay is quieter, as well the subwoofer I installed is less punchy, it's tapped to the rear speakers for power.

Without getting too off topic, what do you mean tapped into the rear for power?

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Cuzoe said:

Without getting too off topic, what do you mean tapped into the rear for power?

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Sorry no idea why I wrote that. I tapped into the rear speakers, for my LC2i, not for power lol. I mean for signal.

Do the new rabbits not have the Fender Audio system like the R's?

I find the fender system to be awesome without any modifications.

VDubb said:

Do the new rabbits not have the Fender Audio system like the R's?

I find the fender system to be awesome without any modifications.

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Nope. They have the base MIB-II with no CD, no HD radio, no SAT, no NAV, no station icon art, and no Car-Net.

To the OP, I wouldn't come to any conclusions until you program that Helix!!! It will be night and day.

VDubb said:

Do the new rabbits not have the Fender Audio system like the R's?

I find the fender system to be awesome without any modifications.

Click to expand...

Need at least SE plus option package. In Canada, Fender and DCC are standard on the Rabbit for less money with DAP optional. New Jetta GLI Autobahn comes loaded up, with Beats Audio, for same price as US Rabbit.