I look on the websight they use 1/4in od lines it does not say what the id is. so I do have a bigger line then they use
yea my 26in hadley does same blow by sound at high psi, i gave up on using it. i later figured out it was because i used 3/8 line and a 3/8 valve which was getting to much air to the horn. i believe a semi uses 5/16 or 1/4 line and valve
well 1/4in id is to big apparently. I think what I am going to do is take a ball valve and put it right after the electric valve then have some one hold the horn on while I turn the valve on untill it gets the best sound
the cool thing is that horn has like a all you can eat buffet on that 14 gallon tank so I can take my time