• Registered: 2023-01-04
  • Posts: 29

Topic: OVR and digital clipping detection

According to Pro and DAC manual, "OVR appears for the rear XLR and TRS outputs at +2.5 dBFS, since the ADI-2 Pro FS R (or DAC) has this digital headroom. For the Phones outputs, OVR appears from +1 dBFS, since their analog circuitry limits the headroom here."

Preparatory question: Does the digital headroom apply when the Hor. Meter is set to "Pre-FX"? In other words, what is the input signal level for which the meter shows OVR with "Pre-FX" meter setting?

Real question: What is the easiest way to detect clipping on the input over a period of time (hours)? Something like a permanent "flag" set if an OVR occurred. Is DIGIcheck capable of something like this with pre-FX loopback over USB?

ADI-2 DAC FS
ADI-2 Pro FS R BE

2 Reply by KaiS (edited by KaiS 2023-03-24 18:05:57)

  • KaiS
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Re: OVR and digital clipping detection

WowFlutter wrote:

...Real question: What is the easiest way to detect clipping on the input over a period of time (hours)? Something like a permanent "flag" set if an OVR occurred. Is DIGIcheck capable of something like this with pre-FX loopback over USB?

Usually the DAW serves for this.
At least here.
Would be very time-consuming to play a file in realtime to find it’s peak level.

Keep in mind, in the digital domain “Over“ is just a definition.
The max. level exist in digital is fullscale, 0 dBFS.
There are no bits higher than that.

A common definition for “Over” is 3 adjacent samples reaching 0 dBFS.
There are other definitions too, like ISPs (Inter Sample Peaks).

Best to leave a little headroom, 0.2 to 1 dB.

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3 Reply by MC

  • MC
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Re: OVR and digital clipping detection

DIGICheck can do this easily, even directly on the record (and playback) signal.

On the unit threshold for all overs is highest 24 bit sample value.

Regards
Matthias Carstens
RME

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  • Registered: 2023-01-04
  • Posts: 29

Re: OVR and digital clipping detection

MC wrote:

DIGICheck can do this easily, even directly on the record (and playback) signal.

Excellent, this is what I need: "infinite hold marker".

MC wrote:

On the unit threshold for all overs is highest 24 bit sample value.

Do I understand this correctly: on the device, the highest observed 24-bit value (since power-up?) is taken as the benchmark for OVR?

ADI-2 DAC FS
ADI-2 Pro FS R BE
  • Registered: 2023-01-04
  • Posts: 29

Re: OVR and digital clipping detection

KaiS wrote:

Would be very time-consuming to play a file in realtime to find it’s peak level.

Indeed, but sometimes the input is not a file, i.e. not available for offline peak search.

KaiS wrote:

Keep in mind, in the digital domain “Over“ is just a definition.
The max. level exist in digital is fullscale, 0 dBFS.
There are no bits higher than that.

Sure - that's digital signal basics. But I guess this remark could be useful to non-technical forum users.

ADI-2 DAC FS
ADI-2 Pro FS R BE

6 Reply by MC

  • MC
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Re: OVR and digital clipping detection

I have no clue what 'since power-up' shold mean here.

Regards
Matthias Carstens
RME

MC's Website

  • Registered: 2023-01-04
  • Posts: 29

Re: OVR and digital clipping detection

MC wrote:

I have no clue what 'since power-up' shold mean here.

Ok, then I didn't understand correctly your second remark. Could you please clarify what you meant and if you were referring to the OVR implementation on the device or something else?

ADI-2 DAC FS
ADI-2 Pro FS R BE