Almost. It's far less effective if the 45 doesn't keep the same port width throughout. Calculate the distance from the port corner to the outside corner the port width away. Draw a line from that point diagonally to the side and rear of the enclosure, and that's the width of the piece you need.Shouldn't be.To 45 the corners you need a piece of wood about 4" wide, cut the edges on a 45 (both sides) and fit it into the corner.Kinda like crown molding but vertical.Kinda like thisView attachment 26501062
Just remember this will take away from the internal volume as well.
