Logic Pro 9 MIDI Latency

Andre Favreau

When I record my virtual instruments, I want it to record and reflect exactly when I played.

Since we know there is MIDI latency going IN to our plugins, should we do something to adjust that or should we leave it like that, and is that possible in the environment?

Basically, when we play our keyboards, should our MIDI recordings reflect when we press the keys or when we monitor the sound? When we play, are we more influence by what we play or by what we hear?

Would it be the same for a MIDI drum? Does that depend on if you you put headphones or not, because playing on a Midi drum, you really feel and hear your stick hitting the pad.

Any opinions or advice?


Playback latency does not matter because you play to what you hear and the latency compensation writes the recorded data to the right position in the timeline.

But latency while monitoring your recording signal does of course matter. And with virtual instruments there is not much chance to get rid of this latency. You may switch unnecessary plugins off in the DAW to bring the overall latency down. You can try a standalone version of your virtual instrument or another plugin host, which may be faster.

But with bigger instruments and if you are an emotional, quick player, and time-sensitive, you have to get used to the modern feeling: Let us wade through honey.

Solution: Hardware.
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Playback latency does not matter because you play to what you hear and the latency compensation writes the recorded data to the right position in the timeline.

By "latency compensation", do you mean I should check the PLC in Logic Preferences, or just that it does it naturally?

And when I record a second Audio Instrument track, should that PLC be checked if there are no insert plugins on the first track?

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PLC should normally be on in most instances, although it won't counteract recording latency it does compensate for playback. Think of it as moving back tracks so the sound lines up with what you see in the arrange page. For example logic may calculate that a midi software instrument takes 1/2s from hitting a note to responding with the sound, in that case logic will play the midi 1/2s early (the same applies to latency inducing audio effect plugins.) So it won't help as your playing in a passage but it'll make sure tracks already there will play in time with each other.

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A more extreme description, far from reality:

Let's say, due to special plugins, your plugin latency would be 10 minutes. Now you hit the record button and takes 10 minutes until the playback starts. This is no problem for the musicians, because they play right now to what they hear right now. And it is no problem for Logic, because it captures the incoming sounds and writes the data 10 minutes earlier in the timeline. This recording would be ok!

Of course, 10 minutes isn't a realistic latency and I doubt that Logic would handle it, but I think the example makes clear why we say "PDC always on". It is a simple matter of math. Play 1 second later, write 1 second earlier. Play 0.2 seconds later, write 0.2 seconds earlier. Without PLC all overdubs would be out of time. Turn it on.


A note on interface latency: It gets added to the plugin latency. To avoid timing problems we should measure it and not just believe that the interface reports the correct value to Logic. If it doesn't, time shifts cumulate with each overdub and the whole arrangement gets out of time more and more.


So, if the DAW handles plugin- as well as interface latency, there remains only one problem: monitoring latency. Whenever you monitor through the DAW, you will get the full latency in your headphones or speakers and you cannot do anything against. If this turns out as a problem, you got to find other methods for monitoring.
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My Record Delay in Audio Device Preferences is set to -88 samples for my MOTU 896 Mk3 and to 0 on Fireface 800. I did the ping test with the I/O plugin.

I will keep the PLC set to "Audio and Software instrument Track" and will put it to "All" when I add plugins to Bus, Aux and Output channels.

Does that sound right?

So what I have left is to set my "MIDI Output Delay". So far I discovered I should put it to -40.7ms @ 1024 buffer size. But I'm still messing with the routing and various buffer size at this point...
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