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dac 20bits with SCD1 16bits output as transport?

OK people,correct me about:I have a scd-1 as transport with a Cello reference dac,that use UV22 super cd encoding processing,fully feature 20 bits high resolution(as specs described).I found in my sistem(JRDG Concentra 2+ Apogee Duetta Signature)a radical upgrade with this dac over my scd-1 in both(sacd & regular cd ways)when using good recordings,specialty with XRCD`s or HDCD`s.The output signal of the scd-1 is 16 bits as transport.The dac features sample rates (32k,44.1k or 48k) & resolution (16 or high),but no matter I use 20 bits recordindgs is glued in (44.1k & 16).Today I tried using a Arcam FMJ CD23(24/96)as a transport too,and was the same.After compared sounds of both, the Cello kept his place with a huge diference too.I`m really happy how is sounding,but still interested of what I`m loosing under the hood of this (48k & high)lights.I apreciate HELP with this "catalog question" or someone with expirience with this dac before. THANK YOU,KIKE
kike
fineberg
151 posts
 
The question has nothing to do with the DAC. The format of Cds are defined in a publication which is used to make sure that players and media work together. So ALL CDs are sampled at 44.1 kHz and 16 bits. Many CD players have DACs which use a higher rate than the Redbook (most outboard DACs as well), however the CDs are still 44.1/16. These DACS convert that data with signal processing algorithms to a higher rate for conversion to analogue. This 'oversampling' or 'upsampling' (depending on the technique can theoretically improve the conversion (though quality of the analogue stages and implementation of the circuit can be as important to the overall sonic result). The readouts on DACs usually refer to what is coming in (in the case of a CD always 44.1/16) not how the internal processing is happening. SACD does encode on the disks higher sampling rates and bit depth, but there is not yet a transmission standard so ALL SACD player output data like Redbook CDs when used as transports. HDCD's do have a way of coding higher resolution withing the redbook data stream so if your DAC has a decoder, these can sound very good. XRCDs are just high quality recordings and pressings, I think. Data-wise they are not different.
ghostrider45
449 posts
 
Well said, Fineberg. XRCD's are still 16 bit but use a special high quality mastering process to derive the 16 bit CD data from a higher resolution source.

BTW, the HDCD processor samples at 88.1 khz and 20 bits (if I remember correctly). It applies psychoacoustic priniciples to reduce the data stream to 44.1 khz and 16 bits. The HDCD encoder applies a fixed set of processes to perform the data reduction. It encodes information on the process used at a given moment by modulating the low order bit of the 44.1 khz output stream.

The HDCD decoder in your player/processor decode this information and applies the appropriate inverse process instant-by-instant to the 44.1 khz 16 bit data stream from the HDCD to generate a 44.1 khz 20 bit stream for the DACs.

Also the HDCD decoder incorporates a reconstruction filter that is a perfect complement to the filter applied on the encode side.
kike OP
9 posts
 
Fineberg &Ghostride45, your information was helpfull and well receved,thank you so much, Kike
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