sa friends. I recently got an lpg kit on my vehicle. For this reason, I had to remove my 2-inch hertz es300 subwoofer. I am using the pioneer 307 d4 now, but I am not satisfied. Free air bass came to my mind. my goal is not to take up space in the trunk. But let me come, I heard that some of my senses, if I wear free air under the glass, I can not get good bass because the car is hb and it won't work properly. A passing hawk approached me and I heard the bass sound just as I wanted, both outside and inside the car. I went and asked him what you are using as a subwoofer. said the boy pioneer. I said "Can you open the trunk and show it?" I was surprised, did I give so much noise under glass? Anyway, it came to my mind, but the only question mark was the vehicle hawk and it was sedan, maybe it sounded nice. If I was sure I could get the same tone and sound on the hb vehicle, I would do it. I will put 1 free air bass 2 sets oval in back or 2 free air bass 1 set oval. I am looking now when I put the pioneer 307 d4 there is no space in the trunk, there is 3 4 cm gap between the port and the trunk lid. I think I can not get the bass sound because this gap is not enough for air pressure to be released. I think my user will have air pressure. If there are friends who use free air bass in the hb vehicle in 206 or can the audience listen to this?