Sound Inputs

The sound system accepts inputs from four sources:

• the built-in microphone
• digital audio from the internal optical drive
• call progress audio from the internal modem
• USB audio devices connected to the USB ports

Built-in Microphone

The iMac has a built-in microphone located at the bottom of the display. The analog signal from the microphone is converted to a digital signal by the Tumbler audio circuitry.

The nominal SNR of the internal microphone is 65 dB.