just go Automotive Garage at garage sales and search for soundproof and u will know
this car is cheap becuz it have almost no soundproof
the only part that have soundproof is the floor
other part like bonnet, door, trunk, fender, roof ..all have no soundproof
that's why the engine sound is noisy when u sit inside
that's why when u knock the door..it sound empty
that's why road noise and outside noise can be heard...door also cannot close like myvi
want to soundproof ...u need to go every shop to ask how much they charge, what material they use and how many layers they apply
or u can buy from garage sales and DIY at home...much cheaper
conclusion...the whole car can be soundproof to prevent sound...but will make the car more heavier
same theory like cinema soundproof their wall to avoid sound coming in and out
yea...but at least proton should have put soundproof since its family car....for persona, it came with soundproof..the whole car feels quieter alot then previous gen2/waja.....