< p> 2016 - aiming to excellency. Designing an excellent woofer for a reasonable price. That fits Plug& amp Play-style to BMW underseat OEM locations. A couple of decades of experience working with high quality speaker manufacturers helped to understand that even smallest details make great difference to final result. < br> < br> 2017 - testing and finishing. Product development had gone so far that raw version of final product is built. These were installed to a car that took part in EMMA ( European Mobile Media Association ) car audio competitions in Master OEM class. Result was Finnish Championship. Rest of the year was used to pay attention to every little detail and finishing the product ready for production. Aiming to best possible value for money got a name Four Audio SW8-BMW.< br> < br> 2018 - towards the best. Excellent woofer was now ready for production. Using it as a starting point it was time to take the next step. Towards the best woofer. Frame, cone and surround were already the best possible ones. Magnet was changed to a double-magnet to achieve a higher BL for even better cone control. Modifying spider gave even more lower frequencies. To play lower it is needed to have more cone travel and higher power handling. These things were achieved with changes to voice coil. This is how AI-Sonic BMW-SW8 was born. < br> < br> 2019 - excellent and the best. Done. Only thing left is to make a decision. Do you want excellent woofers for a reasonable price? Or do you want to pay a little more for the best ones? No matter how you choose, you definitely get the best value for your money.< br> < br> This speaker is not directly suitable to use in BMW Top HiFi ( Harman/Kardon, Logic7, Hifi System Professional DSP etc ) systems with codes S688A/S677A/S752A. This is because the amplifier can not handle 2 ohm load. However this speakers works very well in HiFi package S676A and S674A and in basic package without OEM amplifier.< /p>