Gary L Koh
CEO, Genesis Advanced Technologies
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Is this possibly down to slight impedance mismatch causing reflections (whether connector or chip-hardware)?
Reason I ask is that I never see this myself when using AES-XLR digital connections (use 1m most of the time but had longer in comparison).
This aside, one thing this raises that I feel is of interest is how some products can support 192/24 over their single RCA S/PDIF while many do not try to implement this, seems to be a combination of all that is so far discussed including quality of the S/PDIF receiver chip/etc.
Thanks for the update. However, I am still of the opinion that cables need a burn in process including Coax and probably even HDMI. But, you have demonstrated to yourself and it confirms my/our findings that different Coax cables sound different and in different lengths which is counter to what many claim. Did you have a chance to also compare different HDMI cables and in different lengths as well?
Richard A. Nelridge
Going over one of the links I gave it comes out to this:
Every sample is transmitted as a 32-bit word (subframe). These bits are used as follows:
0-3 Preamble (see links; special structure)
4-7 Auxillary-audio-databits (used for 24 bit recordings however I think its invalid to use this as 24bit data for AES/EBU XLR)
8-27 Sample-Actual Audio Data (can set up to 20 bit recordings max)
A CD-player uses only 16 bits, so only bits 12 (LSB) to 27 (MSB) are used. Bits not used are set to 0).
To transmit 24bit recordings it must used the bits relating to 4-7.
28 Validity When this bit is set, the sample should not be used by the receiver. A CD-player uses the 'error-flag' to set this bit.
31 Parity (bit 0-3 are not included)
So for every 32bits transmitted (this is data and other stuff as shown above), we have an overhead for audio between 8-to-16bits (depending if 16,20,24 bit recording).
This is repeated for each channel, so the above subframe example would be for 1 channel, then the next subframe will be the other stereochannel.
The preamble is the bits used to ensure the break is seen between each channel and can also hold the sync information.
That sync info is different to the DAC clocking, as the DAC clocking is embedded with the data (how this changes its looks is also shown in the links).
Ah where it was asked, the bitrate frequency is 2.8mhz when transmitting CD.
Edited for corrections.
Last edited by Orb; 02-03-2011 at 08:48 AM. Reason: Edited for corrections on bits used and how