As one would expect the mid-bass driver of Borg is custom designed and manufactured exactly for the purpose.
10.25 inch mid/bass units are relatively unusual and crossing them well to HF units is not trivial but FinkTeam is relatively unusual: a technical challenge is just a design exercise that may take a little longer to solve. The benefits of a 10.25 inch mid/bass once heard are difficult to forget. A level of dynamics and naturalness around voices that is unusual and a richness to the sound without bloom or boom (in a well-designed system) that just sounds right. Smaller 2-way systems sound anaemic after hearing a 10 inch.
The Borg’s mid/bass unit features similar thinking to the WM-4’s bass driver: low hysteresis surround (it too looks like a pro driver), a large three inch voice coil for better control and power handling and a light stiff paper cone.
Of course, it includes all the normal FinkTeam design essentials: an aluminium shorting ring on the centre pole to reduce voice coil inductance change with position and to reduce flux variation as a function of voice coil current.
The die-cast aluminium chassis is fully vented for low air speed, as is the voice coil former, both reducing distortion and compression.
All this brings a dynamic low-coloration drive unit with high power handling and very low thermal compression.