What sound board material to use

I am building my first instrument, a cuban mahogany with maple core 36 string harp. After all my reading, I am confused. With today's technology is sitka spruce equal, better or worst than using 5 ply Aircraft birch laminate. As I understand it, the cost is about the same. The laminate is stronger and lasts a lot longer. Sound is about the same???? until the spruce ages about 10 years. By that time I figure the spruce will need some sprucing up.

Can you luthiers input your knowledge please.

Use Sitka spruce. It has the properties of being light for its strength(as does the plywood),but also transfers vibrations very rapidly. Lyon and Healey harps use Sitka spruce for their soundboards with good reason. So does Steinway pianos.