TestGenerator sine wave distortion

Nuendo
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1

I noticed that the TestGenerator in Nuendo 11 distorts significantly as soon as you play a sine wave louder than -6db.

To be on the safe side, I compared to the TestGenerator in my Cubase 10.5 version, where this Bug did not occur.

2

Are you sure this is a bug ?

Seems more a stereo to mono conversion that create a signal heavier than 0 dBFs when you inject more than - 6 dBFs before conversion, saturating the audio interface.

3

I’m pretty sure.
I have tested it with mono and stereo tracks, with mono tracks the distortion starts at about -3dbFS. My True Peak Analyzer does not show any levels above 0dbFS.

And Nuendo processes internally with 32-Bit Floating Point operation, so even if signals are above 0dbFS, there shouldn’t be any distortion.

4

And Nuendo processes internally with 32-Bit Floating Point operation, so even if signals are above 0dbFS, there shouldn’t be any distortion.

Yes internally. But if something is higher than 0 dBFs on the audio output it will clip. If the stereo to mono conversion is done for example in the control room you will not see this clipped level on your meters.

I had this problem recently for a mono monitoring output (Nuendo 8). Mono summing was the culprit.

I can’t see another reason. A bug in the Test generator seems very improbable.

Check the level on the audio output, using an external meter.

5

I have found my mistake. I routed my stereo output AND the control room output to my audio interface at the same time, which caused the signals to add up.

Thanks for your help!

6

Classic user error for me too. ”Where is the clipping coming from…?” Ususally find it fast when it happens. But really, I see no reason that this particular routing is ”allowed” by the application. I might be wrong though, happends all the time.

7

Then you ignored the warnings?

8

When this has happened to me it’s always been ”automatic”/unitentional, when moving projects between computers with different soundcards and output configuration. Also never yet in N11, still only using N11 on my portable rig. I did not even know there was a routing warning.

best regards
Johannes

9

If you trying to set your outputs to already used ports you will get a warning that these are in use.