I haven't heard of this device but it sounds like a hard surface for the french horn sound waves to bounce from and to reflect out into the audience. To keep the sound reflections within the "sound" of the orchestra, I wouldn't have the angle too far from vertical. My guess is that the board probably needs to be around 10 - 15 degrees back from the vertical. This should reflect the waves slightly up and over the orchestra.


MY SONGS...
Audiophile BIAB 2025