[PlanetCCRMA] Problems with a quite complicated audio system

Michele Spinolo michele.spinolo@tin.it
Sun Jun 19 11:02:04 2005

Dear guys,

I am writing here because I have some problem with my setup.
It is composed by:

-Linux based audio workstation (Fedora Core 3 with PlanetCCRMA, RME
-Z-sys z-8.8a lightpipe digital detangler
-RME ADI-8 Pro
-A modified SACD/DVD-A/DVD/CD player which is capable of outputting 6 (5.1)
discrete PCM channel (for SACD a DSD->PCM conversion is performed,
converting DSD to 24bit/88.2Khz PCM signal)

On the workstation AlmusVCU is running, which is used as a real-time
The system is connected as follows:

modified SACD/DVD-A/DVD/CD player-->(3 s/pdif cables)-->Z-sys z-8.8a-->(1
ADAT cable)-->RME HDSP 2496 ADAT 1 input-->(1 ADAT cable from ADAT 1
output)-->RME ADI-8 Pro ADAT input

the clock signal is generated internally by RME ADI-8 Pro (48Khz), which is
connected by word clock BNC cable to RME HDSP9652, which is setted in slave
Z-sys z-8.8s does not have an internal clock, so this is provided through
its input 1 by ADI-8 Pro ADAT output; the Z-sys unit is also setted with SRC
ON, so it resample all incoming signal to 24bit/48Khz (48Khz is provided by
ADI-8 Pro) on output.

Now the problem is the sound is very crappy, similar to what you can hear
when DAC is not synched with source signal: switching SRC to OFF on Z-sys
unit provides an even more crappy sound.

I tried all different clock routings I can think to, but never solved the
problem: does anyone can provide some general (I know it will be hard to
"get into" this setup) rules for clock signal routing in setups like mine?
I also tried to play music directly in the audio workstation sending it to
RME ADI-8 Pro (AlmusVCU allows this) and everything sounds fine, so I think
the problem is given by Z-Sys unit.

Thank you very much in advance to everyone who will reply!