Meridian Digital Audio Processor Meridian 518 User Manual Download

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MERIDIAN 518 USER MANUAL

1992, 1993,

1995

Summary of Contents for Digital Audio Processor Meridian 518

Page 1: ...MERIDIAN 518 USER MANUAL 1992 1993 1995...

Page 2: ...vanced operation using the Remote Control 18 Putting the 518 in Standby 18 Coming out of Standby 18 Muting the sound 19 Menu Keys 19 Operating 518 as Resolution Enhancer Type 1 19 Volume control 19 Ga...

Page 3: ...products 43 Radio interference 43 Cleaning 44 Maintenance Service 44 Part 3 45 Appendix 1 Noise Shapes 45 Appendix 2 Hints on Mastering with noise shaping 47 Appendix 3 RS232 49 Appendix 4 Resolution...

Page 4: ...edgements Trademarks etc Boothroyd Stuart Meridian and Meridian are registered trademarks of Meridian Audio Ltd Super Bit Mapping is a trademark of Sony Corp Testers The processing in 518 has been bet...

Page 5: ...is not essential as part of the operation currently being discussed Standby Italic form normally refers to the state of the 518 In some in stances a key and the status of the equipment share the same...

Page 6: ...nnections need to be made to other components in your system Communication connections have to be made to most of the other Meridian components in your system in order for them to act as one sys tem T...

Page 7: ...itch Twin PLL 42MHz DSP Digital Output Front Panel Control Computer D1 D3 RS232 D2 Out Internal block diagram for 518 Opt 518 is a 2 channel digital audio computer with four inputs see the diagram abo...

Page 8: ...like it requires a very sensitive power amp and has difficulties with impedance matching hum noise and frequency response in the passive control The Meridian 518 can provide an enormous improvement in...

Page 9: ...it DACs may give an audible background hiss when connected directly to a power amplifier The extent of this noise depends on the sensitivity of the power amplifier and speaker used and of course will...

Page 10: ...de jittering element is of great importance to some CD players and of enormous significance to any LaserDisc player as they tend to have relatively high jitter output If you want to use a LaserDisc p...

Page 11: ...current track number Meridian Surround improvement The Meridian 565 is a world beating surround decoder One of its unusual features is the ability to accept digital signals directly to the DSP decodi...

Page 12: ...to digital converter ADC The Mastering processor provides these important functions at each stage de jittering matching wordlengths output to input translating between consumer and professional seria...

Page 13: ...istener Much of this technology is proprietary to Meridian RS232 control The 518 supports direct RS232 control from a PC effectively turning it into a 2 channel DSP peripheral Customising features As...

Page 14: ...ings which are remembered for each Source are Gain not volume in Control Unit mode DSP Dither In Out Standby The entire 500 Series is designed to be left connected to AC power at all times This Standb...

Page 15: ...ttom red key on the Remote Control As you adjust the volume setting the display will change to show the cur rent source and volume number For example would indicate that you were listening to a Compac...

Page 16: ...input If input is from a device which is known to use some of the 24 data bits for non audio data or status1 the number of input bits must be equal to the number of input audio data bits Both professi...

Page 17: ...is not already pre emphasised If the incoming signal is pre emphasised the red Emph light indicates this Emphasis is the recommended mode for most program material providing the DAC system is correctl...

Page 18: ...full code normally sounding benign on short overloads and displays a clip message like ClipL 89 The clip message will indicate whether the overload occurred on Left Right or both Clipping in DSP has...

Page 19: ...1 Note Do not use Resolution Enhancement mode if you want the 518 to provide the volume control Use Type 0 Volume control The 518 does not provide the main system volume control in Resolution enhancem...

Page 20: ...ation summary On the 518 front panel Key Action Source Selects Source or input Display Cycle the display through Processing option with gain in dB Dither option with gain in dB Input output choices wi...

Page 21: ...ching a preamplifier on and off Some like the Meridian 205 555 or 605 incorporate DC offset protection that may be triggered by this process Meridian active or digital loudspeakers are inherently proo...

Page 22: ...1 and needs no customising to become operational There are a very large number of different configurations possible This section tells you how to change the configuration Customising general procedur...

Page 23: ...o Normal To revert to Normal 1 Switch off the 518 using the power switch on the back 2 After half a second switch the 518 power on again Making changes to an existing setup Config is a configuration e...

Page 24: ...have the Type you want displayed wait one second for 518 to action the choice 7 Switch off the 518 using the power switch on the back 8 After half a second switch the 518 power on again to restore Nor...

Page 25: ...he product address is 1 The Meridian 500 Comms system allows for up to eight products of the same type operating on the network Unless you are setting up a Multiroom system or are advised to do so by...

Page 26: ...incoming emphasis flag1 If in doubt chose N Emph Y is not needed in normal use Setting the Volume mode for 518 In Config mode 1 Press Display until you see a display like In the 500 Comms system there...

Page 27: ...S SV DAB DAB Radio RD Betamax m Dig Sat DSat LP LP Camera Ca ADC ADC Tape 1 T1 Video 8 V8 R Reel Reel Tape 2 T2 CD V CD V FM tuner FMTun CDR Cr CD I CD I AM tuner AMTun Cable Cb CD T CD T MW tuner MWR...

Page 28: ...lume keys until the correct one is indicated 2 Make changes for all the source options by pressing Source Note When customisation is complete switch the power off and then on again to restore Normal m...

Page 29: ...these do not usually have the degree of shielding or an impedance of 75 Cable intended for UHF applications like antenna down lead is also unsuitable since it does not shield adequately in the 1 30MHz...

Page 30: ...2 Press Clear on the handset Each unit will display One unit will then be designated as the controller and display All the other units will be configured as non controllers and display The system is...

Page 31: ...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 p...

Page 32: ...ual features of 518 operation when used in mastering or Multimedia processor mode Type 2 Please refer to the normal operating instructions on page 15 for more details Meridian 500 Comms warning We str...

Page 33: ...uency response but the level of the signal level is adjusted using a precision dithered multiplication All the front panel keys are available to specify processing 1 Press DSP again The display will s...

Page 34: ...nts of clipping cannot be detected Making Recordings Case 1 The recording is made to the final carrier DAT or CDR at 16 bits a 16 bit A D 518 CDR use Bypass b 20 bit A D 518 CDR use Emphasis if the ma...

Page 35: ...Shape A In set to number of bits on the recording Out set to the number of bits used in the editor Transfer to the final carrier Case 8 Editor and final carrier have same word size In this case use By...

Page 36: ...g using white TPDF dither Each shaper also has a different degree of HF boost The parameters are summarised in the table below Shaper Advantage 44 1kHz 48kHz Normal Pre emphasis Normal Pre emphasis Fl...

Page 37: ...signal Dither Dither is an essential lubricant if a digital audio channel that includes processing is to remain transparent Transparency in a digital channel is the result of maintaining linearity at...

Page 38: ...ition to the noise floor A background to this and a method of calculating dynamic range is given in the paper 2 referred to on page 31 of this manual From a users point of view the noise floor is dete...

Page 39: ...are unique since the noise shaping is designed for that circumstance and the pre emphasis is effected in the DSP If we used pre emphasis on the example of the previous section the resulting CD could h...

Page 40: ...g Frequency 32kHz 48kHz Twin PLL Second phase lock loop minimises jitter at 44 1kHz to approx 3pS rms Input word selection 16 18 20 22 24 bits Output word selection 16 18 20 22 24 bits Channel status...

Page 41: ...e will be quieter when it is stopped CD may also be quieter when it is stopped producing so called digital silence The 518 has a 16 bit capability from input to output on analogue sources When the vol...

Page 42: ...sts contact your dealer EEC This product has been designed to comply with the limits set out in EN55013 and EN55020C REMEMBER to switch all units off before changing any connections Cleaning When clea...

Page 43: ...erent shapers compared with the flat spectrum dither level for the same word size 0Hz 5kHz 10kHz 15kHz 20kHz 25kHz 20dB 0dB 20dB Noise spectrum Frequency Above noise spectrum using High Pass additive...

Page 44: ...kHz 20kHz 25kHz 30dB 20dB 10dB 0dB 10dB 20dB 30dB 40dB Noise Spectrum Frequency Above noise spectrum for Shape B at 44 1kHz 0Hz 5kHz 10kHz 15kHz 20kHz 25kHz 30dB 20dB 10dB 0dB 10dB 20dB 30dB Noise Spe...

Page 45: ...oise Shapes 45 518 User Guide 0Hz 5kHz 10kHz 15kHz 20kHz 25kHz 30dB 20dB 10dB 0dB 10dB 20dB 30dB 40dB Noise Spectrum Frequency Above noise spectrum of shape D at 44 1kHz Above noise spectrum of shape...

Page 46: ...ed variations in this performance between players On normal music this strategy results in a minor modification to the waveform and it usually passes unnoticed The introduced sample is of similar size...

Page 47: ...rfect differential linearity there is no longer any reason why successive bits will maintain a precise 2 1 ratio The effect of this is also equivalent to quantisation at the linearity level of the con...

Page 48: ...Sources send one of CD RD LP TV T1 T2 CR CB TX V1 V2 LD Numbers send one of N1 N2 N3 N4 N5 N6 N7 N8 N9 N0 DP decimal point Menus send one of ML MR MP MM for w e n s Source send one of PR previous PL...

Page 49: ...n have been skilled at dealing with this since 1983 When a jittered digital stream is fed to a DAC the sound is degraded typically a listener will describe it as harsh glassy or bright or lacking in s...

Page 50: ...he digital chain For digital systems to be transparent dither is needed this is described on page 37 Whether the dither is added at the analogue digital conversion stage or later it produces a defined...

Page 51: ...he audible effect of noise in subsequent processing or digital filters in DACs or in the analogue electronics Getting this right is easy 518 immediately tells you if had to clip the output because you...

Page 52: ...ee that the highest frequencies are boosted by nearly 10dB in the channel on the disc Figure 4 Showing CD pre and de emphasis curves The 518 obtains resolution enhancement in making CD recordings by u...

Page 53: ...phasis with the gain reduced to 2 or 3dB You are still winning on resolution with most DACs up to 6dB 10Hz 100Hz 1kHz 10kHz 20 0 20 40 60 80 100 dB spl HP_Deem HP 18 16 Figure 5 Showing the effect on...

Page 54: ...mber of different levels This high frequency lubricant tends to smooth out truncation and linearity problems in real world DACs Try the various shapes and see which one you like best in your system DA...

Page 55: ...17 33 DSP speaker improvement 10 Dynamic range 41 50 Dynamic range explained 38 Emph light 18 Emphasis explained 38 Emphasis light 18 EPROM version number 18 Gain control 19 Help 41 Hiss 41 Input cha...

Page 56: ...lts 21 RS232 48 Service where to get 42 Setup see Customising automatic 30 how to get into 22 Specifications 40 Standby display 14 getting into 18 to get out of 18 Surround sound 11 Switching on 14 Tr...

Page 57: ...Notes 57 518 User Guide Notes...

Page 58: ...Notes 58 518 User Guide...

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