The number of normal speakers is 16.5 inches (6.5 inches). Some owners of the model are not satisfied with the sound that is made by the regular acoustics. You can replace speakers with more powerful and expensive, and you can limit the noise insulation of Hyundai ix35 doors, after which the quality of the sound inside the passenger compartment shows noticeably.
It is recommended that the doors be glued to the doors with three layers of noise insulation. When you change the speakers, you need to change the amplifier. Sometimes the replacement of the head device improved the sound even without changing the speakers.