First, you have to investigate on the DCX2496 spdif input side. I doubt is uses top grade components and it may be of some interest to mod this DCX2496 (clocks, psu etc...)
Now if you'd like to mod and AVR to add 4 spdif outputs, there will be absolutely no digital loss during this I²S=>SPDIF conversion ; the master clock used should be the same that the one feeding the DACs thus the quality of conversion is not dependant on the chips used but on the clocks inside the AVR. High-end AVRs shouldn't be too weak on that parameter.
The length of the cable should be approx 10 to 20 centimeters (sorry guys, I don't speak your inch language...). With proper grounding, this will perfectly carry audio signals sampled at 48kHz.
rfbrw said:
from lexicon's page :
For maximum flexibility, each of the main audio outputs has independent crossover, speaker distance, and output level controls. The crossovers can be adjusted in 10Hz increments from 30 to 120Hz. The MC-12 HD is also THX Ultra2-certified and integrates the processing and enhancements of the THX Ultra2 standard.
WOW ..what an impressive feature!
xovers adjustable in 10hz from 30 to 120hz...
exactly what i am looking for ..
NOT
Johnix said:
i read that the clock signal is compressed within the SPDIF signal and not with the I2S, so any conversion between the 2 introduces some jitter
not too sure on how much though..wasn't mentionned
so do you believe that sending out spdif signals would do it ?
don't know if i'll have much time to mod every single dcx input ..i'll probably have to mod already all the outputs to get better DACs in there
If you want to roll your own DD/DTS decoder, both are open standards since they're used for terrestrial TV broadcast. DTS is an ETSI standard, and Dolby Digital is the audio component of ATSC, known there as "A/52".
DTS: Go to this site - http://pda.etsi.org/pda/queryform.asp - search for "DTS Coherent Acoustics". What you'll want is ETSI TS 102 114 V1.2.1 (2002-12), you'll have to register (free) on the site to get it.
Dolby Digital: http://www.atsc.org/standards/a_52b.pdf
There are also software libraries for decoding these two, "libdca" for DTS and "liba52" for DD, that you can use as a software reference.
Now, these won't cover Dolby Digital Plus, Dolby TrueHD, or any of the new DTS Neo:whatever modes. Also, if you actually implement and sell a system based on these specifications, you'll need a license from Dolby or DTS.
As far as hardware to run this stuff on, this could be anything from a DSP chip on a custom board to a off-the-shelf PC with a multichannel soundcard. That all depends on your capabilities.
DTS: Go to this site - http://pda.etsi.org/pda/queryform.asp - search for "DTS Coherent Acoustics". What you'll want is ETSI TS 102 114 V1.2.1 (2002-12), you'll have to register (free) on the site to get it.
Dolby Digital: http://www.atsc.org/standards/a_52b.pdf
There are also software libraries for decoding these two, "libdca" for DTS and "liba52" for DD, that you can use as a software reference.
Now, these won't cover Dolby Digital Plus, Dolby TrueHD, or any of the new DTS Neo:whatever modes. Also, if you actually implement and sell a system based on these specifications, you'll need a license from Dolby or DTS.
As far as hardware to run this stuff on, this could be anything from a DSP chip on a custom board to a off-the-shelf PC with a multichannel soundcard. That all depends on your capabilities.
JinMTVT said:
the SPDIF DIT chip is simply a I²S to biphase encoder, adding preamble and various other bits but is synchronous to the global clock of the AVR. So if you have (significant) jitter before conversion, you'll have also (significant) amount of jitter after. But if you feed proper clock to your DIT stage, forget about jitter.
I agree on the point that changing the (cheap) DACs on your DCX will greatly improve the whole thing
rfbrw said:
info on this can be found on the DCX thread ???
John : great !!!
so i will be looking for the correct AVR in the coming months , and then i'll open it up and post it in here!
i hope that you will be of assistance, again
as you have prooved very helpfull mon ami
thanks
GMarsh : i do not wish to go at that extent ..
i do not posess the required skills/knowledge
for software/chip standalone,
unless a kit or something similar to diy kits is available.
i'd rather mod a commercial , working AVR to get all the features at the same time, than invent something that will take very long time to complete and will not provide me with all what i need.
and then the recent avr will support all those other multichannel signals and more
+ video switching and balbalbal ..
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