N2 Timber Selection
In recent years I've mostly used Blackwood for the backs and sides of acoustics because I find this timber provides a balance of the qualities found in Rosewood, Mahogany and Maple guitars. The sound and video samples provide a comparison of the characteristics of the timbers I normally use but, to help with your understanding, here's an attempt to put those qualities into words:

• Mahogany - Light but strong, loud and clear, bright treble compact mids.
• Rosewood - Resonant, deep warm bass with a sweet, light treble.
• Blackwood - Like Koa, slightly less bassy than Rosewood, slightly less trebly than Mahogany, beautifully balanced, clear tone.