Audionaut
Major Contributor
So, I don't know exactly, but I suspect that, in simple terms, both Genelec and earlier KEF models used oblong (“racetrack”) woofers not because the shape is inherently superior, but because it addresses practical system-level constraints more effectively than a round driver.But thinking in absolute terms why would you just a less fundamentally less perfect shape if there's no real need? I still don't get it.
A racetrack diaphragm allows for a more effective cone area within a limited baffle width or height, which could help maintain a compact front geometry and better overall integration—whether that means preserving controlled directivity around a coaxial driver in Genelec designs or fitting substantial bass capability into relatively slim enclosures, as with the KEF B139B.
Since these drivers are typically used in the bass region, where wavelengths are long, their geometric disadvantages are largely irrelevant in practice. The same reasoning applies today in modern soundbars, where the extremely low profile often necessitates elongated drivers simply to fit sufficient diaphragm area into a very shallow form factor.
An additional side effect is that membrane resonances are no longer rotationally symmetric but spread across different modes along the long and short axes, effectively distributing and shifting potential breakup behavior instead of concentrating it into a single dominant peak, which can make it easier to manage.
That would be my explanations.
