_Ilya_
New Head-Fier
- Joined
- Dec 22, 2005
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Hi, Guys.
Recently I investigated all information about HDCD, including data sheets for HDCD processors. Seems that HDCD operates as follows:
Data range from -30000 : 30000 is linear. Range above and below is non linear. Multiplier coefficients are recorded in sub-channel (part of audio CD format). Sub channel is not big enough to keep additional 4 bits, but it can keep multiplication coefficient.
In other words HDCD data format is a 2 pieswise interpolation to logarithmic scale. Full range is appropriate to 20 bit. Data precision at any point is 16 bit. (technology similar to voice A-law, M-law compression).
HDCD played on standard CD equipment will distort high levels.
HDCD played on separate transport and processor may be distorted because if sub channel is not transmitted, but processor is HDCD capable, processor will try to apply HDCD decoding because it will find HDCD patterns in upper levels, but without sub channel it does not know how to amplify it. The result is floating level (The same may be achieved if you copy HDCD using NERO but do not copy sub channel).
HDCD can not be saved in .wav because sub channel will be lost. HDCD processor will find patterns in peaks, led will flash.
In general HDCD is a clever solution, giving 20 bit dynamic range with 16 bit precision. Good thing it is not multichannel. I have a very good stereo but I do not know how to listen SACD when it is 5.1...
Why HDCD sounds better ? -
Only because producing labels do not apply compression ! If you simply record LP using 20 bit ADC you will find it can not be recorded on 16 bit CD !!! LP data range is about 20 bit and data recorded linear. After compression you get specific "CD" sound. In this terms all formats giving 20 and more bits dynamic range are all the same ! Data goes linear and no distortions. All other differences are negligible. DAC specific, processing... all this does not matter, actually.
SACD, HDCD, DVD-a - all of them seems to have audio material like it was originally recorded, ie linear.
Regards.
Recently I investigated all information about HDCD, including data sheets for HDCD processors. Seems that HDCD operates as follows:
Data range from -30000 : 30000 is linear. Range above and below is non linear. Multiplier coefficients are recorded in sub-channel (part of audio CD format). Sub channel is not big enough to keep additional 4 bits, but it can keep multiplication coefficient.
In other words HDCD data format is a 2 pieswise interpolation to logarithmic scale. Full range is appropriate to 20 bit. Data precision at any point is 16 bit. (technology similar to voice A-law, M-law compression).
HDCD played on standard CD equipment will distort high levels.
HDCD played on separate transport and processor may be distorted because if sub channel is not transmitted, but processor is HDCD capable, processor will try to apply HDCD decoding because it will find HDCD patterns in upper levels, but without sub channel it does not know how to amplify it. The result is floating level (The same may be achieved if you copy HDCD using NERO but do not copy sub channel).
HDCD can not be saved in .wav because sub channel will be lost. HDCD processor will find patterns in peaks, led will flash.
In general HDCD is a clever solution, giving 20 bit dynamic range with 16 bit precision. Good thing it is not multichannel. I have a very good stereo but I do not know how to listen SACD when it is 5.1...
Why HDCD sounds better ? -
Only because producing labels do not apply compression ! If you simply record LP using 20 bit ADC you will find it can not be recorded on 16 bit CD !!! LP data range is about 20 bit and data recorded linear. After compression you get specific "CD" sound. In this terms all formats giving 20 and more bits dynamic range are all the same ! Data goes linear and no distortions. All other differences are negligible. DAC specific, processing... all this does not matter, actually.
SACD, HDCD, DVD-a - all of them seems to have audio material like it was originally recorded, ie linear.
Regards.