An over-ear wireless headphones employ Pure Digital Drive system, which allows the headphones to operate without a sound-degrading D/A converter that conventional wireless headphones rely upon. Instead, the ATH-DSR9BT utilizes Trigence Semiconductor’s Dnote chipset to receive the digital audio signal from a Bluetooth wireless transmission, process and transfer it to the driver. The Pure Digital Drive system likewise depends on a re-engineered 45 mm True Motion Driver, which features a lightweight diaphragm with DLC (diamond-like carbon) coating for superlative fidelity. The driver’s 4-core twisted OFC-7N voice coil provides precise control of the diaphragm displacement. The entire driver assembly is housed within a layered aluminum structure that minimizes unwanted resonance and isolates the electric circuitry from the housing’s acoustic space. The Pure Digital Drive system also enables the ATH-DSR9BT to overcome the sonic limitations of conventional Bluetooth wireless transmissions by supporting the 24-bit/48kHz Qualcomm aptX HD audio codec. The headphones can reproduce Hi-Res Audio when connected to a computer or other digital playback device via the included 2.0 m USB cable. The ATH-DSR9BT is equipped with a microphone, volume control and simple tap control, three LED indicators, internal lithium polymer battery provides approximately 15 hours of continuous and can be recharged using the included USB cable.