174. Hooking up Audio andMIDI to the US-2244.1 Hooking up audioTo monitor output from your computer,connect the analog outputs of the US-224 toyour mixer, amplifier or powered monitors.Output volume is controlled by the LINEOUT level pot. If you’ve got a digital mixer,external D/A converter, or other device withS/PDIF input, you may prefer to monitor viathe US-224’s S/PDIF output.To record audio from the US-224 into yourcomputer, simply connect a device to theappropriate input. Microphones should beplugged into the INPUT A or B XLR inputs.Note that the US-224 does not supplyphantom power, so if you’re usingcondenser mics, you’ll need an externalpreamp or power supply. You can connectline-level sources (e.g., keyboards andsound modules) into one of the two LINEINPUTS (A or B). If you wish to plug in aguitar, bass, or other high-impedancesource, simply move the sliding switchbelow the Input Trim control to the “Guitar”position. Finally, digital sources (e.g., CDplayers, DAT’s etc) may be connected to theS/PDIF INPUT.The inputs of channels A and B areavailable as either balanced XLR mic-levelinputs, unbalanced (1/4”) line-level inputs,or S/PDIF digital inputs. Digital output istaken directly from the stereo output of yourdigital audio application. Digital input ischosen in the US-224’s Control Panel, asdetailed in Section 5.1.While it’s possible to use both mic and linelevel analog inputs simultaneously on eitherinput, in actual practice this is notrecommended, as the signal level of theinputs will be summed and very likelyinterfere with each other.Inputs A and B are also switchable betweenthe analog inputs and the S/PDIF digitalinput. The input source is selected in theUS-224 Control Panel main page. (Seesection 5.1 for details).Input level for analog sources is regulatedby the TRIM level pots. NOTE: The INPUTA and B TRIM controls do not affect digitalinput. Sampled audio from the S/PDIF digitalIllustration 4.01 - Connecting audio to the US-224