Ultrasone's S-Logic technology and 40mm gold-plated drivers complete the HFI-2400 ($295) to provide the finest three-dimensional sound. This pair of high-performance headphones also produces 70 Ohm impedance with a frequency range of 10Hz - 25kHz and a sound pressure level of 94dB. It features a folding design and metal shielding that reduces the amount of magnetic radiation.