Ringing the changes

摘要

Meridian's 808.2 Signature Reference represents a significant advance over its 2004 predecessor, the 808. The new machine incorporates Meridian's Resolution Enhancement DSP. This uses a new 1 50MIPS processor to up/oversample the signal to an exact multiple frequency of 176.4kHz with 48-bit internal precision (24-bit output). Meridian claims this 'perfect' or 'true up-sampling' significantly improves sound quality. Meridian also claims that high-definition sound is achieved from CD by using a new digital low-pass filter, claimed to remove supersonic artefacts with minimum phase and without adding ripple or pre-echo. Unlike post-echo, which may be 'masked' by the ear, this is potentially much more audible. Meridian's anti-image filter is claimed to combine a very sharp cut-off with, it claims, no pre-ringing. Meridian says this gives the Signature Reference 808.2 'perfect' timing and significantly improved sound quality to provide higher resolution sound from conventional CDs. The player is built with separate high-current power supplies for each circuit section or sub-system. For improved serviceability, etc, the 808.2 is assembled on a mother-daughter circuit board system. The DVD-ROM transport reads the disc in multiple passes, to improve error correction, and there are two FIFO buffers to help reduce jitter. Even the delta-sigma DAC has been improved.