18mm Baltic Birch vs 15mm Baltic Birch for speakers - stiffness

[Ultralight]

Audio wise, would there be a practical/noticeable advantage with 18mm over 15mm? That's really the crux of my query.

Thanks,
UL

[Loren42]

Originally Posted by Ultralight

Audio wise, would there be a practical/noticeable advantage with 18mm over 15mm? That's really the crux of my query.

Thanks,
UL

There is no way to really know without building both versions in the exact same way and take comprehensive measurements.

There are so many other factors to the equation that it becomes like predicting weather.

Since the quantitative approach is not very practical for the DIY one tends to err on the side of caution and over-engineer things (or at least have an open path to upgrade or correct problems if they arise).

If it were me, I would probably lean toward thicker material so that I can eliminate or reduce one more variable in a system that has so many to begin with.

[Saturnus]

Originally Posted by boywonder

For a given material, the stiffness increases with the cube (3rd power) of the thickness.........for an easy example, take a long 2x4 and place it between two saw horses laying flat, and compare it's stiffness when laying flat to when on edge.....then a 2x6, 2x8, etc.

Your "rules of thumb" are quite close; 18mm cubed is 5832, and 15mm cubed is 3375, and 12mm cubed is 1728. So 5832/3375=1.72 and 3375/1728=1.95 (not quite 2X for either of these, but 1.95 is close). Taking 5832/1728=3.37, so not quite 4X from thinnest to thickest.

I think the roughly doubling holds as the base stiffness per mm is not identical for 18mm/13ply, 15mmm/11ply, and 12mm/9ply.

Btw, if optimum stiff is the most vital aspect which it often is, then consider filmed baltic birch (or really epoxy glued and coated) it has far the greatest base stiffness any non-exotic wood product I know off. It's in many cases also cheaper because the outer coating means that there are no visually aesthetic requirements for this product. The only requirement is maximum stiffness per mm.