Meridian America Meridian 518 manual Part, Mastering Processor

Using 518 for Mastering and Multimedia 31

Part 2

Mastering Processor

The Meridian 518 Digital Audio Processor has been designed to allow the making of better recordings, and in particular to enable the production of high-quality, enhanced-definition CDs.

The predominantly available channels for delivering high-quality sound to consumers is stereo, linear-encoded 16 bit PCM. There is also no realistic prospect of a widely-available improvement on this capability. While CD is limited to 16 bits, we now have A/D converters, recorders and editors operating with anywhere between 16 and 24 bit words.

The Meridian 518 provides the very best quality and combination of signal-processing functions for use when preparing material for issue on media like CD. In fact, using the unique signal processing in 518, CDs can be produced with up to 19-bit subjective dynamic range.

The functions of 518 have been optimised for use in three stages of the production process, namely:

∙on location, processing the signal between the A/D converter and recorder,

∙during transfer of a recording to an editor,

∙during transfer from editor to production master.

In each such step, the word-size can be different, and 518 can make these processes optimal.

The signal-processing used is based on an extensive programme of research, and is implemented in DSP with an internal precision of 72 bits to ensure exceptional transparency. For a very full technical background, please see the papers referred to below: copies may be obtained from Meridian. 1 2 3 4

518 also finds applications in professional or consumer replay situations. Here the precision gain control and pre/de-emphasis processing can replace the system preamp and enhance the dynamic range of a D/A converter – see the earlier sections of this manual.

1J.R. Stuart and R.J. Wilson, "A Search for Efficient Dither for DSP Applications", 92nd AES Convention, Vienna 1991, Preprint #3334

2J.R. Stuart, "Noise: Methods for estimating Detectability and Threshold", 94th AES Convention, Berlin 1993, Preprint #3477

3M.A. Gerzon, P.G. Craven, J.R. Stuart, R.J. Wilson, "Psychoacoustic Noise- Shaped Improvements to CD and other Linear Digital Media", 94th AES Convention, Berlin 1993, Preprint #3501

4J.R. Stuart and R.J. Wilson, "Dynamic Range Enhancement Using Noise- Shaped Dither Applied to Signals With and Without Pre-emphasis", In preparation for AES Convention, Amsterdam 1994.

518 User Guide