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The sound system for the PowerBook computer supports 44.1 kHz 16-bit stereo sound output and input, available simultaneously.
The sound circuitry and system software can create sounds digitally and either play the sounds through the built-in speakers or send the sound signals out through the sound output jack or one of the USB port. The PowerBook computer also records sound data from several sources: the built-in microphone, an analog stereo sound source connected to the line-level sound input jack, or single-channel digital sound from the modem card or from a CardBus card. For each sound input source, sound playthrough can be enabled or disabled. In addition, sound data from digital sources such as CD can be sent to the sound system for conversion to analog output for the speakers and the sound output jack.
The frequency response of the sound circuits, not including the microphone and speakers, is -3 dB at 20 Hz and 20 kHz. Total harmonic distortion and noise is less than 0.05 percent with a 1-V rms sine wave input. The signal-to-noise ratio (SNR) is 85 dB, with no audible discrete tones.