The ADAU1401A is a complete, single-chip audio system with 28/56-bit audio DSP, ADCs, DACs, and microcontroller-like control interfaces. Signal processing includes equalization, cross- over, bass enhancement, multiband dynamics processing, delay compensation, speaker compensation, and stereo image widening. This processing can be used to compensate for real-world limita-tions of speakers, amplifiers, and listening environments, providing dramatic improvements in perceived audio quality. The signal processing of the ADAU1401A is comparable to that found in high end studio equipment. Most processing is done in full 56-bit, double-precision mode, resulting in very good low level signal performance. The ADAU1401A is a fully program-mable DSP. The easy to use SigmaStudio™ software allows the user to graphically configure a custom signal processing flow using blocks such as biquad filters, dynamics processors, level controls, and GPIO interface controls. The ADAU1401A programs can be loaded on power-up either from a serial EEPROM through its own self-boot mechanism or from an external microcontroller. On power-down, the current state of the parameters can be written back to the EEPROM from the ADAU1401A to be recalled the next time the program is run. Each ADC has a THD + N of ?83 dB, and each DAC has a THD + N of ?90 dB. Digital input and output ports allow a glueless connection to additional ADCs and DACs. The ADAU1401A communicates through an I2C® bus or a 4-wire SPI port.