Surround Processor Reviews

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. (Please note that, from this point on, the scale will read +/–1 decibel from top to bottom for pre/pros. We've introduced this expanded scale to more clearly display the subtle differences in Dolby Digital response of the current generation of products.) The left channel measures –0.01 dB at 20 hertz and –0.00 dB at 20 kilohertz. The center channel measures –0.01 dB at 20 Hz and –0.00 dB at 20 kHz, and the left surround channel measures –0.01 dB at 20 Hz and –0.00 dB at 20 kHz. The LFE channel, normalized to the level at 40 Hz, is –0.00 dB at 20 Hz, reaches the upper –3dB point at 111 Hz, and reaches the upper –6dB point at 118 Hz.

The analog frequency response, from the CD input to the main output, measures –0.02 dB at 20 Hz and –0.04 dB at 20 kHz in two-channel mode. Looking at a broader bandwidth, the response measures –0.09 dB at 10 Hz and –30.08 dB at 50 kHz. Response from the multichannel input to the main output measures –0.05 dB at 10 Hz, –0.01 dB at 20 Hz, –0.00 dB at 20 kHz, and –0.00 dB at 50 kHz.

The analog THD+N is less than 0.026% at 1 kHz with a 100-millivolt input and the volume control set to –3. Crosstalk with a 100-mV input was –92.64 dB left to right and –90.41 dB right to left. The signal-to-noise ratio with a 100-mV input from 10 Hz to 24 kHz with "A" weighting was –120.18 dBrA.—AJ