Headphones

Many of Denon's premium headphones use its FreeEdge driver technology. A free-edge drive unit is essentially the same as a conventional moving-coil driver except that it lacks one key component – the surround that provides a flexible joint between the diaphragm edge and the driver chassis. Surrounds are often a source of resonance and can also be distorted by changes in pressure within the enclosed volume behind. And because the surround usually represents a significant proportion of the driver's radiating area, these problems can influence acoustic output. A radical solution is to eliminate the surround altogether but this presents two issues. First, the lack of an air seal at the diaphragm edge can interfere with bass output; and second, a well-designed surround acts as a dissipative termination for bending waves within the diaphragm, preventing breakup resonance. So removing one source of resonance can easily facilitate another – which is what appears to happen in the AH-D5200's FreeEdge unit. KH