What is cMP²?

High-end audio systems are usually unashamedly expensive – they can cost many tens of thousands of dollars. A key part of a modern system is the CD transport, the device that reads Compact Discs and presents a digital signal for conversion into a musical output. The best of these are magnificently engineered and perform superbly but can cost as much as US$20,000.

Computerised audio dominates the recording and professional music world but has made fewer inroads into domestic reproduction. However, there has been inceasing interest over the past year or two in the use of computers as an alternative to CD Transports for high-quality music playback.

Such devices have been termed PC-based CD Transports or Computer Transports. CDs are accurately copied (‘ripped’) onto hard disk and played back through a DAC using appropriate software. In audiophile terms, results range from the acceptable to the excellent but few would dispute that good solutions are either expensive or the preserve of hobbyists prepared to experiment at length with a bewildering range of variables.

This manual describes an open-source DIY audio construction project called the cics Memory Player or cMP². The project evolved over eighteen months and was tested at each stage by members of a PC audio Internet forum. The design is now settled enough to justify publishing a manual. This discusses some key issues associated with digital audio and then provides a step-by-step guide to building a cMP² player. It is not essential to master the theoretical material though beginners at least might find that they repay careful reading.

Central to the project are two new freeware programs. The first is a replacement for the Windows XP shell called cMP which reduces system overheads (‘bloat’) and configures XP for optimal audio playback.

Second is a music player called cPlay. Its place in an already crowded market is justified by a minimalist approach to quality reproduction, radical run-time OS configuration changes, RAM-based playback and integration with SRC's 24-bit/192-kHz-capable upsampler with a signal-to-noise ratio of 145.68 db. 

Tests are described which suggest that cMP² is bit-perfect and capable of delivering signals with what is believed to be an unprecedently low jitter value, Jpp, of 51 ps [RSS].

Realising performance levels as high as this demands the careful selection and configuration of components such as motherboard, processor, power supply and housing and calls for a meticulous configuration of the operating system to prune it of all but essential components.

Building a computerised transport can be daunting but the text is based on the experience of building several working systems. The constructor needs basic, but not expert, computer knowledge.

The project is ongoing but systems built to date suggest that the design goals are being achieved. Others are invited to join the project to develop the UI and offer improvements or additional facilities.

It is hoped that this manual will provide background material for this.

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