Preamp/Processors

The above chart shows the frequency response of the left (aqua), center (green), LFE (purple), and left surround (red) channels at the preamp outputs of the Dolby Digital decoder. The left channel measures –0.03 decibels at 20 hertz and –0.08 dB at 20 kilohertz. The center channel measures –0.03 dB at 20 Hz and –0.03 dB at 20 kHz, and the left surround channel measures –0.04 dB at 20 Hz and –0.03 dB at 20 kHz. The LFE channel, normalized to the level at 40 Hz, is –0.01 dB at 20 Hz, reaches the upper –3dB point at 119 Hz, and reaches the upper –6dB point at 122 Hz.

The analog frequency response, from the balanced input to the balanced output, measures –0.01 dB at 20 Hz and –0.68 dB at 20 kHz in bypass mode. Looking at a broader bandwidth, the response measures –0.04 dB at 10 Hz and –3.22 dB at 50 kHz. In modes that involve signal processing, the response is –0.14 dB at 10 Hz, –0.04 dB at 20 Hz, –0.79 dB at 20 kHz, and –48.75 dB at 50 kHz. Response from the multichannel input to the main output measures –0.11 dB at 10 Hz, –0.03 dB at 20 Hz, –0.03 dB at 20 kHz, and –0.21 dB at 50 kHz.

The analog THD+N is less than 0.022% at 1 kHz with a 100-millivolt input and the volume control set to –3. Crosstalk with a 100-mV input was –92.4 dB left to right and –92.56 dB right to left. The signal-to-noise ratio with a 100-mV input from 10 Hz to 24 kHz with "A" weighting was –95.65 dBrA.—AJ