Meridian America Meridian 518 manuale d’uso

MERIDIAN 518 USER MANUAL © 1992, 1993, 1995[...]

2 518 User Guide Contents Sales and service in the UK ................... 4 Sales and service in the USA ................. 4 Designed & manufactured in the UK by .................................................. 4 Acknowledgements ................................ 4 Introduction ................................ ............ 5 About this manual [...]

3 518 User Guide Simple rules for using 518 .................. 40 Additional technical information ......... 42 Specification ......................................... 42 Help! ................................ ...................... 43 Standby point not lit ........................... 43 Audible hiss at high volume settings ........................[...]

4 518 User Guide Sales and service in the UK Meridian Audio Ltd Stonehill Huntingdon Cambs. PE18 6ED England Tel (0) 480 52144 Fax (0) 480 459934 Sales and service in the USA Meridian America Inc. 3800 Camp Creek Parkway Building 2400, Suite 112 Atlanta, GA 30331 Tel. (404) 344-7111 Fax (404) 346-7111 Designed & manufactured in the UK by Digita[...]

Installation 5 518 User Guide Introduction The Meridian 518 Digital Audio Processor is part of the 500 Series of advanced high-fidelity equipment. In purchasing a Meridian 518 Digital Audio Processor, you have acquired a re fined piece of equipment that will continue to bring you listening pleasure for many years. This manual will enable you to get[...]

Installation 6 518 User Guide Part 1 Unpacking the 518 On opening the carton, you should have found the following parts: • Meridian 518 Digital Audio Processor • Power cord • This manual • 500 Series communications lead If any of these items is missing, please contact your dealer. We suggest that you retain the packing carefully as it provi[...]

Overview of 518 7 518 User Guide Planning setup of 518 Firstly, the 518 is a product for enthusiasts! We designed it for audio and multimedia enthusiasts, keen listeners and those with enthusiasm for the best sound. However, 518 is something of a chameleon. What do we mean by that? This is best explained by seeing what it does: 518 fulfils four ver[...]

Overview of 518 8 518 User Guide Overview as Preamp (Type 0) Conventional analogue systems use a 'preamp' or control unit to gather together the various sources and to control the level of signal fed to the power amplifier so you can adjust volume. Purists know that no matter how well a piece of analogue audio electronics is designed, the[...]

Overview of 518 9 518 User Guide What about analogue sources? 562 518 CD Player LaserDisc DAT LP Tuner Using 518 with a 562 Analogue sources need to be converted to digital before passing through 518. Meridian make the 562 and 562V digital controllers, both of which have very high quality delta-sigma analogue – digital converters. By adding a 562[...]

Overview of 518 10 518 User Guide Overview as Resolution Enhancement Processor (Type 1) There are a wide number of applications for this mode of 518: three examples are described. CD or LaserDisc playback improvement Many installations use the 2-box CD player format of CD transport + DAC. The CD transport provides a digital output, and of course ma[...]

Overview of 518 11 518 User Guide 562 518 CD Player LaserDisc DAT LP Tuner DSP Speaker DSP Speaker Using 518 with DSP Loudspeakers As the diagram shows, a 518 can be placed between the 562 and the Meridian DSP speakers. In this case, the 518 is used – very much as it is for the earlier CD example – to provide further de-jittering and resolution[...]

Overview of 518 12 518 User Guide Overview as Mastering Processor (Type 2) Using 518 as a Mastering Processor 518 Recorder ADC DAT Recorder Mixer The 518 is closely related to the highly respected Meridian 618 Mastering Processor; in fact 518 uses identical DSP to the 618 in this mode. The Meridian 618 has been used for over three years by some of [...]

Overview of 518 13 518 User Guide • De-jittering. This is vital to getting good sound when recording or playing back from a computer-based sound storage system. • Matching wordlengths input to output. Hard disc storage systems tend to use 16 or 24 bits. While 16 bit storage is quite adequate for simple transfer, it does not allow any headroom f[...]

Using 518 in Hi Fi Systems 14 518 User Guide Starting off with 518 Checking Before turning on the power, check once again that you have made all the connections correctly. The 518 is designed to be left connected to AC power at all times and can be run continuously. Switching on The power switch is located directly next to the power inlet on the ri[...]

Using 518 in Hi Fi Systems 15 518 User Guide Note 518 can be used with or without other Meridian equipment. When it is used as the main system control unit it is normally the ‘System Controller’ and operates exactly as described below. Systems including other Meridian control units like 562 or 565 or DSP speakers will always elect for 518 not t[...]

Using 518 in Hi Fi Systems 16 518 User Guide The numbers indicate the number of output bits. C and P represent the choice of consumer and professional channel status formats respectively. Information: 24 audio data bits are always written to the left and right output words but the least significant bits, below the number of output bits chosen, are [...]

Using 518 in Hi Fi Systems 17 518 User Guide Shape C uses flat dither and a 9th-order shaper optimised to MAF. Shape D uses high-pass dither and a 9th-order shaper optimised to MAF. Shape E uses high-pass dither and a 2nd-order shaper optimised to MAF. DSP 1. Press DSP to select the primary processing mode. The display will show: Gain 87 Gain has a[...]

Using 518 in Hi Fi Systems 18 518 User Guide 20C16 67 Input/output choice and gain setting, (This example indicates 20 bits of input and 16 bits of output in consumer format), or 44k1 67 Sampling frequency and gain. If there is no input signal the display would indicate no lock as follows: N.L. 67 Emphasis Light There is a light on the front panel [...]

Using 518 in Hi Fi Systems 19 518 User Guide Muting the sound The mute facility cuts off the sound by setting the volume level to zero. To mute the sound 1. Press Mute on the Remote Control. The output will mute and the display will change to: To restore the sound 1. Press Mute a second time. The volume level and display will be restored. Menu Keys[...]

Operation summary 20 518 User Guide Memory In Resolution Enhancement mode, 518 maintains a continuous memory of the DSP, Dither, Gain, In and Out settings for each source. So, if you had determined that, e.g. CD should always use Gain 0dB but that Radio could always use Emphasis and +2dB, then 518 will remember these and automatically reconfigure i[...]

Customising 518: overview 21 518 User Guide Customising 518, an overview 518 is a very sophisticated device with a huge number of options to allow you to set up exactly the system you need or to experiment with new possibilities. Programming 518 is a straightforward process and you should not be timid about experimenting. Although the setup is stor[...]

Customising 518: overview 22 518 User Guide • whether or not the Bypass DSP option is available. 2 • whether or not a blank display option is allowed. • whether or not the Emphasis DSP option is adaptive – i.e. reacts to the incoming emphasis status. • choices on how the volume control operates and displays. Details of these are described[...]

Customise 518 using Type 23 518 User Guide Caution Some power amplifiers are very susceptible to small surges that may result from the process of switching a preamplifier on and off. Some – like the Meridian 205 or 605 incorporate DC-offset protection that may be triggered by this process. Meridian active or digital loudspeakers are inherently pr[...]

Customise 518 using Type 24 518 User Guide • Source-Logo-input mapping as shown below. Source Logo Type 0 Input Type 1 Input Type 2 Input Comms type CD CD D1 D1 D1 1 Radio RD D1 D1 N 2 LP LP D1 D1 N – TV TV D1 D1 N – Tape1 T1 D2 D1 D2 – Tape2 T2 D3 D1 D3 – CDR CR D1 D1 N – Cable Cb D1 D1 N – Text Tx D1 D1 N – VCR1 V1 D1 D1 N – VCR[...]

Customising 518 using Config 25 518 User Guide Selecting the controller mode In Config mode: 1. Press Display until you see a display like: 2. Use the and , Volume keys to choose between: • Auto, meaning configuring can be automatic • Cont, meaning the 518 will be the system controller • N.Con, meaning the 518 will not be the controller Setti[...]

Customising 518 using Config 26 518 User Guide Setting the Blank display option for 518 In Config mode: 1. Press Display until you see a display like: This means that a blank display is one of the options offered by the Display key. To remove this option chose N. 2. Use the and , Volume keys to choose between Yes or No. Setting the Emphasis option [...]

Customising 518 using Config 27 518 User Guide The gain of 518 can either be displayed in absolute dB in the range -99dB to +12dB, or as a Meridian volume number 0 to 99 – where 87 corresponds to 0dB. 2. Use the and , Volume keys to choose dB or ##. Setting up sources For each of the twelve source selection keys on the Remote control you choose a[...]

Customising 518 using Config 28 518 User Guide 3. Use the and Volume keys until the correct logo is indicated – see the list above. 4. Make changes for all the source options. Note If you select the logo ‘ N’ the 518 will ignore that key on the Remote control and that source will not be offered in the Normal source menu. Changing the input fo[...]

Connecting 518 29 518 User Guide Connections There are three types of connection that need to be made to the 518. • power, see page 14 . • digital audio, see page 40 . • communications, see page 30 . Digital audio connections Digital connections are made: • from the digital outputs of 518 to your digital power amplifiers, digital loudspeake[...]

Connecting 518 30 518 User Guide Communications connections Communications connections are only made to other Meridian equipment. The following sections describe the major points. To connect to other Meridian 500 Series equipment 1. Connect one of the COMMS sockets on the rear panel of the 518 to one of the COMMS sockets on another 500 Series unit,[...]

Using 518 for Mastering and Multimedia 31 518 User Guide 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 consum[...]

Using 518 for Mastering and Multimedia 32 518 User Guide Description The Meridian 518 Digital Audio Processor is a general-purpose digital- domain DSP engine that operates on or between consumer or professional interfaces at sampling frequencies between 32 – 50kHz and with up to 24 bit input and output. The supplied user programmes are intended f[...]

Using 518 for Mastering and Multimedia 33 518 User Guide Memory In Mastering Processor mode, 518 maintains a continuous memory of the DSP, Dither, Gain, In and Out settings for each source. So, if you had determined that, e.g. D1 is an 18 bit source that should always use Gain 0dB but that D2 is 16 bit and can always use Emphasis and +2dB, then 518[...]

Using 518 for Mastering and Multimedia 34 518 User Guide 20C16 +2 Input/output choice and gain setting, (This example indicates 20 bits of input and 16 bits of output in consumer format), or 44k1 +2 Sampling frequency and gain. If there is no input signal the display would indicate no lock as follows: N.L. +2 Clip Display Some of the processing mod[...]

Using 518 for Mastering and Multimedia 35 518 User Guide • Out set to the number of bits in the recorder. Transfer to editor Case 5. The recording and editor are the same word size In this case use Bypass. Case 6. The recording has fewer bits than the editor In this case use Bypass. Case 7. The recording has more bits than the editor In this case[...]

About the Noise Shapers 36 518 User Guide Noise shaper characteristics Each noise shaper presents a different degree of subjective noise reduction – we call that its ‘advantage’ – compared with normal dithering using white TPDF dither. Each shaper also has a different degree of HF boost. The parameters are summarised in the table below. Sha[...]

Additional technical information 37 518 User Guide 518 Operating Background Transparency in digital systems Digital audio gives a unique opportunity to deliver exceptional sound quality in a recording or broadcast. In the first decade of this technology, considerable progress was made developing the gateways – i.e. A/D and D/A conversion. The pro[...]

Additional technical information 38 518 User Guide Unfortunately, although this process is generally understood, it is not common practise to employ correct dithering procedures at these stages. In fact, practising engineers are often under the misapprehension that dither is only needed once in a system, or that if there is sufficient noise in a re[...]

Additional technical information 39 518 User Guide source, the average and peak spectrum level declines with frequency above a few kHz. Best use is therefore made of the channel by pre- emphasising high-frequency signals to an extent where they are more likely to occupy the capacity of the channel. De-emphasis is applied on replay or reception and [...]

Additional technical information 40 518 User Guide the dynamic range of the signal itself. A typical application may be a full- range DSP volume control, where e.g. a 16 bit input is modified by a gain control function and passed out to a DAC of 18 or 20 bits. In these cases: • If the programme material permits, use pre-emphasis • Use Shape A o[...]

Support information 41 518 User Guide Help! Standby point not lit Check the following: 1. There is AC power connected to the socket on the rear of the 518 2. The power switch on the rear panel of the 518 is turned on If the 518 will still not illuminate, check any fuses in your power supply and the fuse in the inlet of the 518. If these are all int[...]

Support information 42 518 User Guide FCC WARNING : This equipment generates and can radiate radio fre - quency energy and if not installed and used correctly in accordance with our instructions may cause interference to radio communications or radio and television reception. It has been type-tested and complies with the limits set out in Subpart J[...]

Appendix 1 – Noise Shapes 43 518 User Guide Part 3 Appendix 1 – Noise Shapes The graphs in this appendix show the relative noise spectra in dB for the different shapers, compared with the flat-spectrum dither level for the same word-size. 0Hz 5kHz 10kHz 15kHz 20kHz 25kHz -20dB 0dB 20dB Noise spectrum F requency Above: noise spectrum using High-[...]

Appendix 1 – Noise Shapes 44 518 User Guide 0Hz 5kHz 10kHz 15kHz 20kHz 25kHz -30dB -20dB -10dB 0dB 10dB 20dB 30dB 40dB Noise Spectrum F requency Above: noise spectrum for Shape B at 44.1kHz 0Hz 5kHz 10kHz 15kHz 20kHz 25kHz -30dB -20dB -10dB 0dB 10dB 20dB 30dB Noise Spectrum F requency Above: noise spectrum for Shape C at 44.1kHz[...]

Appendix 1 – Noise Shapes 45 518 User Guide 0Hz 5kHz 10kHz 15kHz 20kHz 25kHz -30dB -20dB -10dB 0dB 10dB 20dB 30dB 40dB Noise Spectrum F requency Above: noise spectrum of shape D at 44.1kHz. Above: noise spectrum of shape E at 44.1kHz.[...]

Appendix 2 – Hints on Mastering 46 518 User Guide Appendix 2 – Hints on Mastering with noise-shaping There are a few difficulties associated with employing noise-shaping schemes to maximise the subjective dynamic-range of a digital audio channel. These are now reviewed. Vulnerability of the signal The available dynamic range in a channel is onl[...]

Appendix 2 – Hints on Mastering 47 518 User Guide dynamic range is extended. Implicit in this theory is the fact that the digital channel has near-infinite differential linearity, i.e. each bit has a magnitude precisely twice or half the magnitude of the next. When this signal is applied to a D/A converter some problems may arise. First the D/A p[...]

Appendix 3 – RS232 48 518 User Guide Appendix 3 – RS232 The 518 may be operated via its RS232 interface. Set the communication settings as follows: • Baud rate 9600 • Data bits 8 • Stop bit 1 • Parity none The 518 is operated by sending short command strings on the RS232 interface. Each command is terminated by a <return> (dec. 13[...]

Appendix 4 – Resolution Enhancement 49 518 User Guide Appendix 4 – Resolution Enhancement Resolution enhancement in 518 depends on six techniques. 1. De-jittering 2. Dynamic-range optimisation with Gain 3. Dynamic-range optimisation with Pre-emphasis . 4. Dynamic-range optimisation with Noise-shaped Dither . 5. DAC enhancement by using high-fre[...]

Appendix 4 – Resolution Enhancement 50 518 User Guide The block diagram on page 7 shows the twin phase-lock-loop which 518 uses to smooth out the digital sample stream. Each loop acts as a progressive 'flywheel' – following the average sample rate exactly – but removing short-term speed unevenness. Dynamic-range The dynamic range of[...]

Appendix 4 – Resolution Enhancement 51 518 User Guide Figure 3 . Showing the audibility of noise in the LP system for comparison with digital channels. Dynamic-range optimisation with Gain The noise-floor of a digital system is determined absolutely by the lowest preceding wordsize. For nearly all commercial material this is 16 bits. 518 allows y[...]

Appendix 4 – Resolution Enhancement 52 518 User Guide are boosted. This boost process is called pre-emphasis. Now, in the channel, the energy is more evenly distributed with frequency, and any high-frequency noise and distortion in the channel is further below the signal. In other words we get a better distortion and noise result in the channel. [...]

Appendix 4 – Resolution Enhancement 53 518 User Guide such converters are used. Meridian has always used correct analogue de- emphasis in its designs. By wrapping 72-bit precision pre-emphasis and analogue de-emphasis around a DAC, it effectively gains: • one bit noise reduction • two-bit increase in high-frequency resolution • more than te[...]

Appendix 4 – Resolution Enhancement 54 518 User Guide 10Hz 100Hz 1kHz 10kHz -20 0 20 40 60 80 100 d B sp l SBM Shape C Shape D Figure 6 . Showing the effect on audibility of the 518's Shapes C and D (C using pre-emphasis). DAC enhancement by using high-frequency dither The graphs above and in Appendix 1 (page 43 ) show that some of the noise[...]

Index 55 518 User Guide Index 500-Series, 5 562, 9 565 using with, 11 Acknowledgements, 4 AES/EBU digital audio connections, 29 Analogue sources, 9 Autoconfigure, 30 Background noise, 41 Bypass, 33 Cable for digital audio, 29 CD improvement, 10 Clip display, 18, 34 Communication making connections, 30 Config how to get into, 22 how to use, 24 overv[...]

Index 56 518 User Guide Pre-emphasis explained, 38 Programming. see Customising Radio interference, 41 Recording, 34 Remote control, 18 Repacking 518. see Unpacking Resolution enhancement explained, 49 Resolution enhancer, 19 Restoring defaults, 21 RS232, 48 Service where to get, 42 Setup. see Customising automatic, 30 how to get into, 22 Specifica[...]

Notes 57 518 User Guide Notes[...]

Notes 58 518 User Guide[...]