Adding this 'AIM Option 0 - A8x8' module to your Symphony chassis gives an extra 8 channels of I/O. 8 Analog I/O + 8 AES/Optical I/O (16 channels of I/O simultaneously).The I/O Modules are the sound and soul of Symphony I/O, and represent 25 years of Apogee R&D and design excellence. These powerful Modules deliver Apogee's core competency, superior sounding digital audio recording. With 5 available I/O Modules, you can choose from standard configurations or customize the following: channel count, analog to digital input, digital to analog output, mic preamps and digital I/O. You compose your Symphony I/O.