Yes, there is soundproof cotton in the middle. Its sound insulation cotton can absorb noise well and achieve good sound insulation effect, and the sound insulation cotton is the best. Cotton will naturally provide corresponding acoustic performance, but whether cotton is needed depends on the design and development goals and the acoustic performance of the engine as a sound source; Generally speaking, this problem is designed to the sound source, that is, the powertrain and related engine accessories, the transmission path, that is, the transfer function from the engine compartment to the driver in the car, and the response, that is, the driver's subjective feeling; To sum up, optimizing feelings can be done from two aspects: optimizing the source of goods or optimizing the path. Therefore, no cotton does not mean that the subjective feeling in the car is poor, and cotton does not mean that the subjective feeling in the car is good.