There are some really good blacksmiths and silversmiths in Liaquatabad and also Lawrence Road, those trumpets are really easy to make for them, it would be better if you curled the lip more outwards, it really helps reducing the buffeting on the edges.
I have placed such trumpets on turbo inlets, the air suction into the compressor was really nice after that, and the menacing vacuum cleaner like howl was really music.