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weird automation visual "delay"


Danny Wyatt

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I'm experiencing something really weird on one of my tracks

I'm automating the send amount

Audibly speaking, it's doing what it's supposed to

If I drag the playhead manually over that automation curve, the send knob increases and decreases according to the curve

BUT when I hit Play, it seems as if the automation is happening BEFORE the actually curve. Again, audibly speaking it's working, it's just that visually it's showing it earlier.

 

Other tracks are normal. Restart the computer, nothing changed.

Any idea what's happening?

 

 

The 2 times the playhead is playing faster, is when I hit PLAY. The slow playhead is me dragging it manually:

1739114148_Kapture2021-05-14at21_26_47.gif.612473bda64ad5a9b2e10a01d455d57a.gif

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That's most likely Plug-in Delay Compensation at work? It's possible that PLC makes the track play early and then visually compensates for the playhead position (but not for the send level knob).

 

But it’s only affecting sends not all automation.

I have another track with the StepFX being automated and it works as expected, but on that same track, the Send behaves as I showed here... super weird...

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I have another track with the StepFX being automated and it works as expected, but on that same track, the Send behaves as I showed here... super weird...

Compensation depends on what creates latency and where in the signal flow the latency is introduced. If you insert say Step FX on a track that sends to a bus that has latency inducing plug-ins then the Step FX automation won't be visually compensated, so the knobs move before its automation curve:

 

latency-automation.gif.5f18113b8d4c4febc764aaa6d41ff3d1.gif

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I have another track with the StepFX being automated and it works as expected, but on that same track, the Send behaves as I showed here... super weird...

Compensation depends on what creates latency and where in the signal flow the latency is introduced. If you insert say Step FX on a track that sends to a bus that has latency inducing plug-ins then the Step FX automation won't be visually compensated, so the knobs move before its automation curve:

 

latency-automation.gif

 

But the automation will always be applied where it’s supposed to, right? Even though it’s visually doing it before?

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But the automation will always be applied where it’s supposed to, right? Even though it’s visually doing it before?

Yes, at least that's the goal of PDC. As you may have heard, PDC has limits, and some complex signal routing can push the limits. Typical examples often involved sidechaining:

 

Automation and PDC is just broken (still in Logic Pro 10.6)

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But the automation will always be applied where it’s supposed to, right? Even though it’s visually doing it before?

Yes, at least that's the goal of PDC. As you may have heard, PDC has limits, and some complex signal routing can push the limits. Typical examples often involved sidechaining:

 

Automation and PDC is just broken (still in Logic Pro 10.6)

 

Thanks for the link. I will check it.

 

I never activate the PDC button on the top bar, but I think I remember it highlights the plugins that are introducing latency, am I right?

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I never activate the PDC button on the top bar, but I think I remember it highlights the plugins that are introducing latency, am I right?

No, that's the low latency mode. PLC is a preference that synchronizes audio signals in the mixer by playing some tracks early and delaying some of the audio streams, but it doesn't have any visual feedback in the UI.

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If the automation is happening at the right times sound wise that is a reason to rejoice!

 

Like David said I think this is probably a matter of the GUI code not being synchronized. Instrument and audio channels achieve plugin delay compensation by feeding the audio and midi early to the separate mixer channel objects. You will probably notice that when you click play, the play head cursor will jump back a little ways and preroll without sound until you start hearing sound at the point where it was before you hit play. That is similar phenomenon where the GUI is following exactly things that are being sent to the mixer early from the sequencer. Internally these are separate objects in logicpro. So logicpro has to tell the sequencer to play a little ahead so that the latent mixer channel will sound on time. Automation is associated with sequencing also. The GUI appears to show the timing of when the sequencer sends stuff to the mixer……in this case early. It’s actually sending everything early, midi, audio, but your latent mixer channel makes the sound come later. The GUI is synchronized to the sequencer, not to the latent sound. The send knobs are in the mixer so perhaps the GUI aspects of the mixer are more synchronized to the latent mixer compared to the automation lane on the tracks view, which is associated with the sequencer thst is being played early/

 

Well some things in the GUI are synchronized to the latent sound. Like the transport clocks and the play head for example. I think automation GUI could be also but for whatever the reason it’s not as of now but hey if the automation is affecting the sound at the right time sonically then i would not worry about it too much.

 

As a similar example, vepro has its GUI meters totally out of sync from the sound when a large audio buffer is used. You see the meters when the Dsp is processed and not when the sound is heard later after latency. Could they fix it? Yes probably they could but there are bigger fish to fry

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