Apple Desktop Computer manual Total harmonic distortion

C H A P T E R 3

Devices and Ports

Total harmonic distortion plus noise (THD+N) as a percentage of full scale for various outputs are shown in Table 3-3.

Table 3-3	Distortion specifications
		Total harmonic distortion
Connector and level		and noise
Line input		0.03%
Line output		0.03%
Headphone jack, open circuit		0.03%
Headphone jack, 32-ohm headphones,		0.1%
–20 dBFS level
Headphone jack, 32-ohm headphones,		1.0%
–1.5 dBFS level

The signal-to-noise ratios (SNR) for various inputs and outputs are shown in Table 3-4. The values shown are unweighted; values with A weighting would be about 8 dB higher.

Table 3-4	Noise specifications
Connector and level		Signal-to-noise ratio
Line output		92 dB
Headphone jacks		86 dB
Line input		85 dB
Internal CD		82 dB

38Sound System