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Cinematic Media Audio (Cinematic Media) asked a question.

September 5, 2022 at 4:16 PM
Digital noise using Pro Tools, DAPS and Focusrite Red4Pre
Hello there, I'm reaching out for help!
I have a Mac mini (2018), 3.2 GHz 6 Core Intel i7, 64GB RAM, Monterey 12.4 running Pro Tools Flex 22.7, DAPS 3.7.2 with a Focusrite Red4Pre, an A16R (for the speakers) and Focusrite R1 with all the correct firmware in the devices.
When I open a session with Pro Tools and DAPS running with Dolby Audio Bridge as output/input and from DAPS to Red4Pre I have digital noises all over the place, more like crackles, regardless if the session has 200 track or 1, and the video goes out of sync and eventually the computer sends a Pro Tools error.
But if I change the PB Engine to Red4Pre directly and close the DAPS the audio is fine and the session runs like a charm, again 200 or 1 track, works great. But if I just open the DAPS, then the digital noises appear again. Any idea will be highly appreciated.
  • 5 answers

  • AdamP (Dolby Labs)

    Hi,

    Just to clarify when using the Production Suite the playback engine in Pro Tools should be the Dolby Audio Bridge and the buffer size must be 1024 at 48kHz. In the Production Suite the input should be the Dolby Audio Bridge and the output should be the Focusrite A16R.

    A couple of other things to check are to make sure the sample rate is correct in the Rednet app and SRC is off, the channel count and sample rate are correct in Audio/MIDI setup.

    Also, in the Pro Tools Playback Engine window, ensure that “Ignore Errors During Playback/Record” is disabled during mastering. It may be enabled while editing, but if it is, ensure that “Minimize Additional I/O Latency” is unchecked, as this will induce 6101 errors regardless of system usage.

    Hope this helps.

    Thanks,
    Adam
    Expand Post

    • Cinematic Media Audio (Cinematic Media)

      Hello AdamP, thanks for your reply, all your recommendations had already been test and the noise still persists, I'm just not sure about the SRC off in the Rednet app, I will and get back to you.
      The output of the DAPS is going to Red4Pre via thunderbolt with Apple converter and Apple TB2 cable and then to the A16R via DANTE in order to be able to use the R1.

  • AdamP (Dolby Labs)

    Hi,

    Got it.

    I'd check the device samplerates in the Dante Controller as they have a way of setting themselves for 192kHz which can also be the cause of noise.


    I'd also suggest trying the Dante Virtual Soundcard (    https://www.audinate.com/products/software/dante-virtual-soundcard) and routing to the Focusrite directly via the Dante Controller.


    For troubleshooting purposes if nothing else. If it works, then you can decide if you want to purchase it.

    Thanks,
    Adam
    Expand Post

  • Cinematic Media Audio (Cinematic Media)

    Hello AdamP, an update regarding the noise. Just change the computer to a MacMini 3.2 GHz 6 Core Intel Core i7, 32 GB of RAM, with same configuration of software and the noise is still present. The computer starts to get the digital noise when the renderer is open.
    If the renderer is close and I select on PT the playback engine to be the Re4Pre, then the audio and the entire session works great. I can send you the session without media if you can give it a try.

    Please advise.

    Thanks for your help
    Expand Post

  • AdamP (Dolby Labs)

    Hi,

    Sorry you are still having issues.

    I doubt the session or the computer used has anything to do with it. It sounds like it is a clocking and/or sample rate issue.

    Can you confirm if a master file recorded by the Production Suite has the noise in the file (showing up in meters)? Or if the noise is present if Pro Tools is closed and you playback a recorded master file (or an exported ADM BWF from Pro Tools)? Also if the noise if present if Pro Tools is open but playback is from a master file rather than the renderer input. And lastly if the noise if present only when the Renderer is chasing timecode (sync button engaged). Just trying to narrow this down. It would also be helpful to look at the Renderer logs to see if there are any errors. These can be accessed from the Production Suite help menu. If you could zip and send along the whole folder that might shed some light on this.

    Please verify that sample rate and framerate in the Production Suite matches Pro Tools. And that the sample rate is set the same in Audio Midi setup, the Dante Controller, and the Rednet App. As mentioned before try disabling SRC in the Rednet app as well.

    Lastly what is the master clock for this setup in the Dante Controller? Is this running on internal clock or is there external word clock input to one device that is set as Master in the Dante Controller.

    Were you able to try the Dante Virtual Soundcard as the output of the Production Suite routed to the A16 instead of the Red4Pre?

    Thanks,
    Adam
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