Hey Angelo,
I apologize if that was vague but I really can't think of a more thorough and to the point way of putting things. If the relative levels of all the orchestral instruments have been published could I ask where? What do you mean by 3-D plot?
That information is most certainly not education for all engineers. I can assure you that a very small percentage of engineers in the US know the information being discussed here. You may though already know of a source where we could get this information. Please specify the publication/website or whatever where this can be found. Better yet post the data that you have and know.
Thanks again and sorry for the confusion!
Rob