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Lavry 3000S, Operation Manual

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Lavry 3000S Operation Manual Download Page 24

Appendix I 

 

LE3000S 

 

22 

 

20.00 2.02k 4.02k 6.02k 8.01k 10.0k 12.0k 14.0k 16.0k 18.0k 20.0k 22.0k 24.0k

FREQ(Hz)

-170.0

-165.0

-160.0

-155.0

-150.0

-145.0

-140.0

-135.0

-130.0

-125.0

-120.0

-115.0

-110.0

-105.0

-100.0

-95.00

-90.00

-85.00

-80.00

AMP1(dBFS)

AUDIO PRECISION FFT

vs

14 NOV 93 13:59:14

20.00 2.02k 4.02k 6.02k 8.01k 10.0k 12.0k 14.0k 16.0k 18.0k 20.0k 22.0k 24.0k

FREQ(Hz)

-170.0

-165.0

-160.0

-155.0

-150.0

-145.0

-140.0

-135.0

-130.0

-125.0

-120.0

-115.0

-110.0

-105.0

-100.0

-95.00

-90.00

-85.00

-80.00

AMP1(dBFS)

AUDIO PRECISION FFT

vs

14 NOV 93 14:00:12

         

           Fig. 9- 16 bit input signal   -100 dB                             Fig. 10- 16 bit input signal  -100 dB 
                    high pass dither applied                                       Acoustic Bit Correction applied 

 

Figure 9 shows the original 16 bit input signal processed with high-pass dither only. Notice that the 
additional distortion is gone.  

Figure 10 shows Acoustic Bit Correction (dither and noise-shaping) applied to the same signal with an 
increase in the effective noise floor.  Acoustic Bit Correction cannot remove truncation distortion in an 
incoming 16 bit signal, but it can avoid additional truncation distortion if additional processing, such as 
sample rate conversion, has been applied. 

Summary of Contents for 3000S

Page 1: ...S 96kHz Digital Optimizer Operations Manual Lavry Engineering Inc P O Box 4602 Rolling Bay Washington USA 98061 http www lavryengineering com E Mail techsupport lavryengineering com Revision 1 4 November 10 2008 ...

Page 2: ......

Page 3: ...urisdiction LIMITS AND EXCLUSIONS LAVRY ENGINEERING DOES NOT BY VIRTUE OF THIS AGREEMENT OR BY ANY COURSE OF PERFORMANCE COURSE OF DEALING OR USAGE OF TRADE MAKE ANY OTHER WARRANTIES EXPRESS OR IMPLIED INCLUDING WITHOUT LIMITATION ANY WARRANTY OF MERCHANTABILITY FITNESS FOR A PARTICULAR PURPOSE TITLE OR NONINFRINGEMENT AND ALL SUCH WARRANTIES ARE HEREBY EXPRESSLY DISCLAIMED LAVRY ENGINEERING EXPRE...

Page 4: ...coustic Bit Correction Screen 8 Store Preset Screen 9 Signal Analysis Screen 10 Test Tone Screen 11 Delay Screen 11 PART II Tutorial 12 Connections 12 Starting Up 12 Input Selection 12 Monitoring Input Data 12 Bar Graph 13 Output Format and Sample Rate Conversion 13 Options Screens 14 Power Up Preset 14 Test Tones 14 Using the Tone Generator and THD N Features 15 PART III Specifications 16 Appendi...

Page 5: ...cursor is not present the UP and DOWN buttons serve to move from screen to screen Edit Screens Press ENTER to introduce the screen cursor at the first editable location Each additional pressing of ENTER will move the screen cursor to the next editable location The settings at an editable location may be changed by the use of the UP DOWN buttons Holding the UP or DOWN button will automatically adva...

Page 6: ...ODE OUTPUT FQ INPUT FQ 44 1K 100 PPM 48 0k BYPASS JITTER ATTENUATION MODE OUTPUT FQ INPUT FQ 48 0K 100 PPM 44 1 kHz XTAL INTERNAL CRYSTAL CONTROLS OUTPUT FREQ SAMPLE RATE CONVERSION 48 0 kHz XTAL INTERNAL CRYSTAL CONTROLS OUTPUT FREQ SAMPLE RATE CONVERSION AES LOCK 44 1 44 1K 100 PPM LOCKS OUTPUT FREQUENCY TO SYNC INPUT AES LOCK 48 0 48 0K 100 PPM LOCKS OUTPUT FREQUENCY TO SYNC INPUT AES WIDE LOCK...

Page 7: ... 24 bit stereo signal into a 96 kHz or 88 2 kHz 16 bit stereo signal The 24 BIT DECODE mode is used to reconstruct the original 24 bit stereo signal Both modes operate at a synchronous 2 1 or 1 2 data rate the original bits are not modified in any way This mode allows high sample rate 16 bit recorders such as those made by Pioneer to be used for wide word recording at conventional sample rates 2 1...

Page 8: ...RD LENGTH 24 OUTPUT WORD LENGTH 16 NOTE reduced word length can be used for rounding For example 20 bits input can be rounded to 16 bits by setting the output to 16 bits IN CATEGORY CD C 1 L 0 OUT CATEGORY DAT C 1 L 0 In consumer mode this screen contains information regarding category C bit and L bit settings pertaining to copy protection and generation information Possible choices X can be 0 or ...

Page 9: ...display mode and the FINE mode with its corresponding reference point from 10 dB to 20 dB In FINE mode the reference LED will be lit and the channel level will be displayed in increments of 0 2 dB around that reference point This is useful for setting precise levels Indications are OFF ON and BIT The BIT mode displays the active bits in the output stream with the most significant bit displayed to ...

Page 10: ... This screen allows the user to set or remove Dither and Noise Shaping Based upon customer feedback and further studies V1 4 software offers High Pass or Flat Dither type and four noise shaping curves Our research taught us two interesting facts a Certain data compression schemes require the dither to have flat frequency response characteristics b Recording engineers preference of dither type high...

Page 11: ...To store settings in the preset press GO Press EXIT to abort the operation The word DONE appears after pressing GO when the storage into non volatile RAM is completed The factory default preset may be recalled by holding down the EXIT button while powering up the 3000S The preset may then be modified and saved by following the procedure above Factory default Preset settings these are stored as the...

Page 12: ...ode enables the Model 3000S to lock to the incoming tone frequency MANUAL mode sets the analysis frequency to the frequency programmed by the TEST TONE SCREEN This allows the notch filter to be manually tuned by the user The Model 3000S s test tones may be used simultaneously with the THD N measurement with input sample rates below 50 kHz To do so first go to the test tone screen and press GO Then...

Page 13: ...ing the CURSOR buttons the tone frequency may be selected in 1 Hz increments between 1 Hz and 20000 Hz 88 2 kHz sample rate mode is limited to 43000 Hz 96 kHz sample rate mode is limited to 46000 Hz Level settings using the CURSOR buttons the tone amplitude may be selected in 1 dB increments between 0 dB full scale and 120 dB An additional step below 120 dB indicated by OFF on the display outputs ...

Page 14: ... Starting Up Apply AC power to the Model 3000S and to your sources and destination devices The Model 3000S displays its ROM version for 5 seconds referring to its internal software version The user may choose to bypass the 5 second wait by pressing any of the front panel buttons The first screen is the main screen The top line of the LCD liquid crystal display shows data associated with the select...

Page 15: ...the CURSOR UP or CURSOR DOWN button for several seconds to quickly scroll through the screens This quick scrolling action will be particularly useful under test tone generator programming of frequency and amplitude Press EXIT to return to the main screen Press ENTER to introduce a cursor Set the output data format to CNS consumer format Move the cursor to output frequency indicator and set it as d...

Page 16: ...ppendix I for more details of Acoustic Bit Correction READ LEFT RIGHT CSBITS When set to LEFT the Model 3000S reads the digital audio information from the left channel this is likely to cover most source material The user may select the right channel Power Up Preset The Preset screen starts with STORE RAM PRESET You may store the present settings of the Model 3000S into the RAM preset press GO or ...

Page 17: ...O button 4 Select THD N screen and press the GO button 5 Read results tone frequency amplitude and THD N You may now adjust unit under test parameters while viewing THD N You may go back and forth between tone generation screen and THD N screen for testing different amplitudes at the set frequency Selecting a new frequency requires you to press GO to re tune the notch Example B optimizing multiple...

Page 18: ...tone 18 kHz tone 48 kHz 48 kHz 107 dB 00045 110 dB 00032 110 dB 00032 48 kHz 44 1 kHz 104 dB 00063 108 dB 00040 105 dB 00056 44 1 kHz 48 kHz 102 dB 00079 107 dB 00045 102 dB 00079 44 1 kHz 44 1 kHz 106 dB 00050 110 dB 00032 119 dB 00035 Output word length 16 bits INPUT OUTPUT 1 kHz tone 10 kHz tone 18 kHz tone 48 kHz 48 kHz 98 0 dB 00126 98 7 dB 00100 99 0 dB 00112 48 kHz 44 1 kHz 97 5 dB 00133 98...

Page 19: ...0 00 70 00 60 00 AMP1 dBFS AUDIO PRECISION FFT vs 13 NOV 93 19 41 24 20 100 1k 10k 20k FREQ Hz 160 0 150 0 140 0 130 0 120 0 110 0 100 0 90 00 80 00 70 00 60 00 50 00 40 00 30 00 20 00 10 00 0 0 AMP1 dBFS AUDIO PRECISION FFT vs 13 NOV 93 18 00 38 Dynamic Range High Frequency Full Scale Performance 1 kHz tone 48k to 44 1k Conversion 18 kHz tone 48k to 44 1k Conversion 60 dB 24 bit word length 0 dB ...

Page 20: ...032 110 dB 00032 110 dB 00032 18 bits 48 Hz 110 dB 00032 110 dB 00032 109 dB 00028 16 bits 44 1 Hz 98 1 dB 00124 98 9 dB 00113 98 5 dB 00119 16 bits 48 Hz 98 3 dB 00122 98 9 dB 00113 99 0 dB 00112 Inputs and Outputs Signal Connector Impedance Isolation AES EBU INPUT XLR 3 110 Ohms Transformer isolated AES EBU SYNC INPUT XLR 3 110 Ohms Transformer isolated AES EBU OUTPUT XLR 3 110 Ohms Transformer ...

Page 21: ...ise shaper off when dither is off Using dither with or without noise shaping requires user discretion Ideal data transfer and processing should retain long word length A single word length reduction and therefore dithering and noise shaping should take place last Figure 1 shows a 100 dB 1 kHz 24 bit tone truncated to 16 bits The distortion is severe Figure 2 shows the same tone with high pass dith...

Page 22: ...te the temptation to optimize the noise shaping curve to the average listener s hearing threshold given a significant variation from listener to listener requires reasonable compromises in tailoring such a curve In other words smooth the curve The improvements offered by dither and noise shaping vary with source material and final word length An A B X test at 16 bit level requires a quiet environm...

Page 23: ...put reducing to 16 18 20 and 22 bit output widths Notice that there is no noise modulation present Figure 6 shows the effect of high pass triangular dither only The more coherent data in the dithered bits the better the dithering process works Note that dithering from 24 bits to 22 bits has a lower noise floor but more visible distortion components than dithering to a shorter word length due to fe...

Page 24: ... 00 80 00 AMP1 dBFS AUDIO PRECISION FFT vs 14 NOV 93 14 00 12 Fig 9 16 bit input signal 100 dB Fig 10 16 bit input signal 100 dB high pass dither applied Acoustic Bit Correction applied Figure 9 shows the original 16 bit input signal processed with high pass dither only Notice that the additional distortion is gone Figure 10 shows Acoustic Bit Correction dither and noise shaping applied to the sam...

Page 25: ...zation noise is shifted from these areas to high frequencies where the ear is less sensitive Noise shaping curves should be selected based upon listening tests of specific material to be dithered 20 00 2 02k 4 02k 6 01k 8 01k 10 0k 12 0k 14 0k 16 0k 18 0k 20 0k FREQ Hz 160 0 155 0 150 0 145 0 140 0 135 0 130 0 125 0 120 0 115 0 110 0 105 0 100 0 95 00 90 00 85 00 80 00 AMP1 dBFS AUDIO PRECISION FF...

Page 26: ...ng with signal amplitude and frequency Such jitter reduction yields noticeable sonic improvement thus complicating the objectivity of listening tests Some manufacturers comparison tests inappropriately compare a high jitter input to a low jitter output Further confusion is due to the fact that digital domain FFT tests do not adequately show the effects of input jitter Listening tests should be bas...

Page 27: ...ffects of low levels of incoming jitter A common indirect approach is based on measuring the THD plus noise reduction at the output of a reference DAC driven by full scale high frequency tone While such a measurement does not quantify jitter it yields in principle the desired end result Real world limitations of reference DAC performance set limits to such measurements DAC performance is typically...

Page 28: ... separately or both simultaneously Distortion and noise Real hardware generated tones contain both distortion and noise Harmonic distortion is referred to as energy residing at multiples of the tone frequency Noise is all other undesirable energy Some common sources of distortion Amplifiers non linear signal processing causes distortion While mostly corrected for by use of negative feedback amplif...

Page 29: ...in music production but are bound to limit our discussion to measurable and objective phenomena Optimizing THD N some engineering considerations Analog amplification good signal to noise ratio requires early signal amplification but with careful attention to tradeoffs between distortions and noise Analog attenuation undesirable from noise standpoint may be required to accommodate signal range limi...

Page 30: ... energy does not alter the outcome Model 3000S begins its measurement by locking to the test tone frequency There are 2 modes user selectable for achieving lock Auto mode Proper locking in the presence of noise and distortion requires reasonable signal to noise and distortion ratio When using Auto mode we recommend starting the test with a large enough signal full scale signals are ideal but locki...

Page 31: ...al audio signals with test tones The unit resumes normal operation when exiting tone generation mode The test tone screen enables setting tone characteristics Frequency 1 Hz to 20 kHz in 1 Hz steps Amplitude 0 dB full scale to 99 dB in 1 dB steps Destination Right channel Left channel or both Test tone quality Tones purity at maximum word length 22 24 bits exceeds full scale performance of 122 dB ...

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