• Registered: 2011-09-15
  • Posts: 42

Topic: 44.1khz - 48khz

I'm curious about something.

My UFX is set to 48khz and Nuendo  v.5.5.3 is also set to 48khz.

I've connected a 44.1 S/PDIF signal from a Roland V-drum to the AES-EBU input on the UFX using a converter cable as described in the UFX manual.

When the audio arrives in Nuendo it is recorded at 48khz (which is what I want), but is the conversion from 44.1 to 48 being done by the UFX or Nuendo?

2 Reply by Randyman... (edited by Randyman... 2012-05-28 02:59:57)

  • From: Houston, TX
  • Registered: 2007-05-11
  • Posts: 1,191

Re: 44.1khz - 48khz

AFAIK, the UFX does not have any form of AES SRC (peeked at the specs - saw no mention of it).  The Digital reciever (the UFX's AES input in this case) must "lock" to the incoming digital signal before any sample rate conversion was to take place, and this is not currently possible in your configuration as I understand it.

You are basically running asychronus (V-Drum input is NOT referenced/locked to the rest of the system), and are likely getting dropouts but they might not be audible unless you really listen (or look) for them.  So, nothing is doing sample rate conversion.  I'm surprised you aren't getting Digital Distortion (clicks and pops) on the AES Input channels...

Nuendo can't do the SRC as it is being fed 48K Digital Audio from the UFX's ASIO Driver.


One additional thought - Do you have the UFX set to "Autosync / SPDIF"?  If so, it might be over-riding the 48K specified rate and be syncing to the V-Drum's 44.1K SPDIF Input via "Autosync".  What does the HDSP Control Panel say when the V-Drums are all patched in and sounding good?
Then, Nuendo might be set to 48K in the project, but it is likely recording at 44.1K if the UFX is set as described above.  Try to record the V-Drums to a track - then DISCONNECT the V-Drums AES input, and play back the track.  Does it play back 8% faster / higher pitched? (Recording @ 44.1K, then playing back @ 48K once you remove the 44.1 SPDIF input that might be used for "Autosync").  Just a hunch...

cool

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  • Registered: 2011-09-15
  • Posts: 42

Re: 44.1khz - 48khz

Randyman... wrote:

AFAIK, the UFX does not have any form of AES SRC (peeked at the specs - saw no mention of it).  The Digital reciever (the UFX's AES input in this case) must "lock" to the incoming digital signal before any sample rate conversion was to take place, and this is not currently possible in your configuration as I understand it.

You are basically running asychronus (V-Drum input is NOT referenced/locked to the rest of the system), and are likely getting dropouts but they might not be audible unless you really listen (or look) for them.  So, nothing is doing sample rate conversion.  I'm surprised you aren't getting Digital Distortion (clicks and pops) on the AES Input channels...

Nuendo can't do the SRC as it is being fed 48K Digital Audio from the UFX's ASIO Driver.


One additional thought - Do you have the UFX set to "Autosync / SPDIF"?  If so, it might be over-riding the 48K specified rate and be syncing to the V-Drum's 44.1K SPDIF Input via "Autosync".  What does the HDSP Control Panel say when the V-Drums are all patched in and sounding good?
Then, Nuendo might be set to 48K in the project, but it is likely recording at 44.1K if the UFX is set as described above.  Try to record the V-Drums to a track - then DISCONNECT the V-Drums AES input, and play back the track.  Does it play back 8% faster / higher pitched? (Recording @ 44.1K, then playing back @ 48K once you remove the 44.1 SPDIF input that might be used for "Autosync").  Just a hunch...

cool

Thanks for the informative reply.

I have not been able to find where to set "Autosync / SPDIF".

I'm getting no clicks & pops on the AES input.

The Fireface USB Settings window indicates the following:

AES Lock 44.1kHz
ADAT1 Sync 48kHz
ADAT2 Sync 48kHz       (ADATs 1 and 2 are a couple of MR816 interfaces linked via Adat (obviously).

Clock Mode:

Sample Rate:  48kHz
Clock Source: Current Internal

The AES sync light on the UFX front panel is flashing, indicating that the input is not syncronous.

Within Nuendo the project is set to 48kHz / 24 bit, Sync: Internal.

As you suggested, I have recorded a part from the V-drums and saved the project.  There are no audible glitches. The project still indicates 48kHz.  If I remove the s/pdif connection from the UFX AES input and replay the recording there is no audible difference - no pitch change. The Pool Window indicates that the wav file is 48kHz / 24bit.  Opening the file in Wavelab also indicates that it is 48kHz / 24bit.

It's weird - but working!