Hi,a audio pen pal from Australia came out of the blue on my computer and was looking for the Mello Monster horn plans from Popular Electronics 1962 Oct.When I finally found them he was so happy he sent me an issue bought on E-bay all the way from( Down Under) to Portland Maine.I have the specs for every piece needed to make the 8 inch coaxial horn.He wants to make a 12 inch Mello Monster.I thought adding 4 inches to every piece's dimention might work.Am I right or wrong?,and is there anyone out there that might have a clue.I ask this to help him and remember I had to go to summer school,repeat geometry.Thanks all,you will be the next American or where ever hero if you can help with this,I will send a copy of the dimentions to you.Thanks......Mark Korda