Meridian America Meridian 518 manual DAC enhancement by using high-frequency dither

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Appendix 4 –Resolution Enhancement	54

	100
	80
	60
dB spl	40
dB spl	20
	20			SBM
		Shape C		SBM
		Shape C
	0
	-20	Shape D
	-20
	10Hz	100Hz	1kHz	10kHz

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-shapers produce quite a lot of supersonic noise. This high level of dither can have a very positive effect on DACs by causing them to represent each level by averaging a large a number 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.

DAC or channel enhancement by word-length matching

Digital systems work best if the input data is matched to the correct wordsize for the device. Particularly where the signal has a larger wordsize than the following device, then truncation distortion will arise. The effects are real, but more subtle the other way round and are to do with jitter and linearity.

In general 518 should be set to match the input and output wordlengths to the incoming signal and following equipment. That will produce the cleanest sound.

518 User Guide

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Contents 1992, 1993 Contents Simple rules for using Appendix 4 -Resolution EnhancementAppendix 2 Hints on Mastering Designed & manufactured in the UK by Sales and service in the UKSales and service in the USA AcknowledgementsAbout the 500 Series IntroductionAbout this manual Conventions used in this manualUnpacking Installing yourGeneral precautions ConnectionsPlanning setup Whats inside a 518?Overview as Preamp Type What about analogue sources? What else do I need to know?Overview as Resolution Enhancement Processor Type CD or LaserDisc playback improvementMeridian DSP speaker improvement Meridian Surround improvement Overview as Mastering Processor Type Overview as Multimedia Processor TypeCustomising features ∙ Normal ∙ Standby ∙ Type ∙ ConfigBasic operation Switching onStarting off with StandbySelecting a source Adjusting the volumeOperating 518 as a Control Unit Type OutShape a DitherFlat Shape BDisplay Advanced operation using the Remote Control Muting the sound Operating 518 as Resolution Enhancer TypeVolume control Menu KeysWith the Remote Control Operation summaryMemory Config control settings Restoring default settingsConfig an overview Customising 518, an overviewConfig sources and inputs How to customiseCustomising, general procedure How to change to Type or ConfigMaking changes to an existing setup Customising using TypeHow to change back to Normal Setting Type ControllerConfig Customising using ConfigHow to use Config Selecting TypesSetting the product address for Selecting the controller modeSetting the system address for Setting the Standby mode forSetting the Volume mode for Setting the Blank display option forSetting the Emphasis option for Setting the Volume displaySetting up sources Choosing source logosVol. dB Changing the input for a source Choosing the Comms type for a source productChoosing the address of a source product Digital input connections ConnectionsDigital audio connections Digital output connectionTo connect to other Meridian 500 Series equipment Connecting to Meridian Digital speakersCommunications connections ConPart Mastering ProcessorMeridian 500 Comms warning DescriptionAs a Mastering or Multimedia Processor Type D1 +2Emph +2 ShpB +2Making Recordings Transfer to editor Transfer to the final carrierNoise shaper characteristics Shaper Advantage 44.1kHz 48kHz Normal Pre-emphasisDigital Audio and Quantisation Operating BackgroundTransparency in digital systems DitherNoise Shaping with dither Dynamic RangePre and De-emphasis No change in sample size Simple rules for usingStep-down in sample word size Step up in dynamic rangeSpecification Additional technical informationHelp Cleaning Maintenance & ServicePart Appendix 1 Noise Shapes NoiseAbove noise spectrum for Shape B at 44.1kHz 0Hz 5kHz 10kHz 15kHz 20kHz Appendix 2 Hints on Mastering with noise-shaping Vulnerability of the signalAudible results of digital errors and editing Requirements for D/A conversionAppendix 2 Hints on Mastering Appendix 3 RS232 Handset FunctionsGoTo Functions Appendix 4 -Resolution Enhancement Jitter and de-jitteringDynamic-range FrequencyDynamic-range optimisation with Gain Dynamic-range optimisation with Pre-emphasisShowing CD pre- and de-emphasis curves Dynamic-range optimisation with Noise-shaped Dither DAC enhancement by using high-frequency dither DAC or channel enhancement by word-length matchingContents IndexIndex User Guide User Guide