Aggregating Separate Devices

From Guide

Many new intel macs including the MacBookPro publish their inputs and outputs as separate devices. Since RiffWorks needs both input and output devices to be synchronized, it can't support this behavior directly. However, Apple has provided a way to aggregate two or more devices into a single device.

• Launch Audio Midi Setup (found in /Applications/Utilities)
• From the Audio Menu choose Open Aggregate Device Editor
• Click the plus button to add a new aggregate device
• Check built-in input and built-in output
• Double click on the name of the device to change it to something easy to understand like "built-in"
• Click Done
• Quit Audio Midi Setup

RiffWorks should now recognize your built-in sound as a valid device.