Horn Waveguide material affect actual sound?

Was wondering if anyone has done comparisons between plastic, metal, and wood waveguides for horns?

Was looking at online and it's either affordable plastic, or stupid expensive cast metal. Since sounds bounce off metal differently than thin plastic, was wondering what opinions were on what's best? Was thinking a dense wood like walnut might produce a good sound w/o being too echoey and was thinking of making one. Like say a walnut tube the driver could thread into, then maybe 3/4" MDF for the actual horn section and possibly a walnut veneer to cover the MDF. Or would I possibly be better off buying cheap 1/8" plates and cutting that for the horn section and welding it together, then add something to the surface (rubberized spray? or veneer). Could that rubberized spray cause turbulence to the sound waves?