I was surprised the speed of sound in spruce is 3000 to 5000 meters per second, this is faster than many metals!
There are many other factors determining acoustic qualities in wood including complex equations, density, longitudinal grain vs. horizontal, Q factors?, varnish and hardness...
Glass transmits sound at over 4,500 meters per second.
Water transmits sound better than air allowing whals to hear each other 100 miles away. At the ends inside a parabala one can hear a whisper 500 feet away...anyway acoustics has many surprises.

In instruments flat spruce is LOUDER than arched wood. Having been around violins to basses for a lifetime. I have accumulated knowledge that is as direct and simple as giving a tap and having a good feeling which is alot more simple than math. I can still be wrong but at most 10% of the time.
I've experimented with the lightest most conductive materials to the heavier densities of carbon or aluminum. Recently I have found a way to coat spruce with glass instead of varnish or laquer. It is only 2 microns or more thick but due to density and hardness acts like a material 100 times thicker. The glass can be either high gloss or matt. It has the abilility to ring. It matches the speed of sound in spruce and believe it or not is easier to work with and cheaper than all the old methods of finishing.

I am entering phase two tests on instuments rangeing from an unvarnished; cello, violin and Martin guitar. Sometimes you can't improve upon nature and sometimes you can but my intrepid nature to try is hopefully on my side. I'd settle for 0-10% improvement since economics is already on my side.