Yamaha RX-V673 versatile speaker options include 7.2ch surround, front presence, bi-amp main speakers or independent Zone 2 operation. Yamaha AV Controller App provides simple network control in either zone. Use advanced YPAO (R.S.C.) auto calibration and sophisticated graphical user interface to expedite setup and ensure accuracy. Expand Apple connectivity with AirPlay and versatile USB input for iPad. Enjoy ECO mode today and 4K video upscaling for next generation super-high resolution displays. Refined digital processing for an enriched audio video experience.