I have a 2017 A3 Sedan/Saloon which came with *** and no subwoofer control. The sound was very boring and flat. I got tired of waiting for Audi to update the MMI firmware to give me control of the subwoofer so I picked up a Pioneer TS-SW2002D2 subwoofer and an amp with speaker-level (high-level) inputs and a remote bass control. I just used the existing wires from the factory sub.
Its probably not the most powerful subwoofer in town but WOW what a difference it made. Trunk space is a priority for me so I wanted a shallow-mount sub which would work in a free-air/IB setup (meaning, not in a box). I would probably be happier with the sound if I had a beefier sub in a box but it sounds pretty darn good as is, and it only sticks down about 1 inch below the rear deck so it doesn't eat up my trunk space.
I'd be very interested in a part number for the Parrot loom mentioned above. I've searched around and haven't been able to find it. I guess the Audison one should work also, so thanks for that link! I've got some quite nice Focal speakers along with an amp/DSP combo for the doors that I was planning to put in at the same time as my sub install, but the sub by itself has made such an improvement that upgrading the rest has become less of a priority.
If anyone is considering going the same route I did, I'd be happy to share more details about my setup, as this was very much a learning experience for me.
Hey there. I am trying to retrofit Audi SS to my stock entry system. My vehicle is 17' A3 FL Sedan, same as yours. I assembled the center mid, and also purchased front speakers and waiting for them to ship. However I suppose I should skip the oem subwoofer and put a different one like you did. My question is does pioneer 8" sit to the oem hole under the rear parcel? Where did you put it in your vehicle? Also what amp have you used? Cheers.