• 44.1
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  • Registered: 2012-11-11
  • Posts: 9

Topic: upsampling and word clock setting

Hi,

I plan to buy a HDSPe AES audio card for my PC.
All my system is described here below:

PC (96 KHz) ---AES---> DSP UNIT (96 Khz) ---AES--->  DAC (96 KHz)
     |--------ANTELOPE TRINITY MASTER CLOCK---------|

Correct me if I'm wrong but the ASIO driver is able to resample audio data.
As I have several sample rates for my audio data (44.1, 48 & 96) I will fix the sample rate to 96 Khz at the HDSPe card.

The Antelope Trinity master clock has 3 independent & simultaneous audio generators.
I plan to connect all my 3 digital units on it but which sample rate I've to set for each of them ?


My first idea was :

PC : 96 KHz / DSP UNIT :  96 KHz / DAC : 96 KHz


But I read this :

If you have a Master Clock in your system, connect one of its word clock outputs to the sound card’s
WCL IN socket, connect a second word clock output to the DAC’s word clock input. Set the Master
Clock’s frequency to match the file sample rate. 
• For data at 44.1, 88.2 or 176.4kS/s, the clock frequency can be 44.1kHz. 
• For data at 32, 48, 96 or 192kS/s the clock frequency can be 48kHz.

Does that mean I've to set the clock frequency equal to the audio data, independently of the upsampling done by the RME card ?

Thanks for clarification

  • From: Germany
  • Registered: 2007-04-10
  • Posts: 9,690

Re: upsampling and word clock setting

Neither the card nor the ASIO driver perforn any sort of upsampling.


Regards
Daniel Fuchs
RME

Regards
Daniel Fuchs
RME

RME Support's Website

3 Reply by 44.1 (edited by 44.1 2012-11-12 12:51:44)

  • 44.1
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Re: upsampling and word clock setting

http://www.dcsltd.co.uk/page/assets/dCS … _Audio.pdf

In the document above (p.30) we can see something like Audio output Format : 192 KHz.
Maybe it's not something we can do with the Asio driver (most something with a 3rd party software).

But regarding the word clock setting, do you have any idea about what frequency to use ?

Is it the one of the  audio data (ex. 44.1 KHz) or the one at the outptut of the RME card (96 KHz or 192 KHz depending how we configured out) ?

regards.

4 Reply by MC

  • MC
  • MC
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  • From: Germany/Thailand
  • Registered: 2007-04-06
  • Posts: 25,431

Re: upsampling and word clock setting

That part refers to upsampling done by the Mac OS Core Audio. The AES card will then spit out 192 kHz. You can easily change that example to 96 kHz. The main problem here is that you keep us guessing what you want to do - as you don't mention your equipment in detail.

Regards
Matthias Carstens
RME

MC's Website

  • 44.1
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Re: upsampling and word clock setting

Hi,

Thanks for your feedback.
What I want to do is to fix the output sample rate to 96 KHz (so to perform an upsampling of my audio files).
Why 96 KHz ? Because my Trinnov unit is limited to 96 KHz (so it's better to have the same sample rate throughout my system).

Regarding my equipment:

1 : PC with RME card (under construction).
2 : Trinnov - room correction (limited to 96 KHz)
3 : Forssell MDAC-8 (accept sample rate up to 192 KHz)

The Anteloppe clock has 3 independent generators.
I'm able to connect all my 3 devices to the same or a separate generator.

For my PC, it is the sample rate of the audio file I've to set on the master clock or the sample rate at the outptut of the RME card (after the 96 KHz upsampling) ?

regards

  • From: Germany
  • Registered: 2007-04-10
  • Posts: 9,690

Re: upsampling and word clock setting

No up- or resampling in ASIO, you'd have to use WDM, with Windows doing the sample rate conversion (if the card is set to 96k in the settings). But with gear like that, I'm not sure that's what you want. You could use an external sample rate converter for better conversion, e.g. RME ADI-192 DD.


Regards
Daniel Fuchs
RME

Regards
Daniel Fuchs
RME

RME Support's Website