Notes recorded before I play them!!

[winkpain]

Time travel?

I'm trying to suss out a possible recording sync issue, and in starting I recorded a MIDI 1/4 note beat from a synth track out to an AUX track to see how the recorded audio lined up with the time grid, assuming there would be delays of varying times with varying latency settings.

To my great surprise, I found that, at higher latency/buffer settings the recorded note, rather than being delayed, it   preceded  the beat it was recorded from!! The higher the latency, the earlier the preceding note would be.   How..... is this possible?!?

The audio is obviously being written, just after the fact, to a location before it actually occurred in time. Is this the "Automatic Delay Compensation"  (which I have never really understood as it is described and seems to be just associated with few and certain plug-ins only some of the times) ?   But the results were the same whether the Delay Compensation switch was on (compensation off) or off (compensation on) and also true with just recording the metronome (to an Aux track) internally OR recording the Metronome with a mic from speaker.

In the screenshot examples I show the extremes of a buffer size of 32 samples (note recorded on the beat), and then 2048 samples (note recorded before the beat).

There is obviously something in the theory of concept of these above settings/process that I have misunderstood.  Please educate me?

I am using a Steinberg UR22 with latest drivers.

 

[David Baay]

It's assumed that when recording a soft synth in real time, it will be driven by live MIDI input from outside the DAW, and the performer will be listening to a delayed audio metronome, so the audio is compensated accordingly. But playback of existing MIDI isn't delayed by audio output latency, so the audio resulting from that is going to end up over-compensated.

Normally existing MIDI would be rendered offline by Freezing or Fast Bounce which will result in correct timing regardless of the realtime buffer setting. If you actually have a need to record soft synth audio from existing MIDI in real time for some reasone, you just need to use the lowest possible buffer size, which should always be the case in any real-time recording situation when audio is input monitored through - or originates from within - the box.

 

Edited April 28, 2020 by David Baay

[winkpain]

15 hours ago, David Baay said:

It's assumed that when recording a soft synth in real time, it will be driven by live MIDI input from outside the DAW, and the performer will be listening to a delayed audio metronome, so the audio is compensated accordingly. But playback of existing MIDI isn't delayed by audio output latency, so the audio resulting from that is going to end up over-compensated.

Normally existing MIDI would be rendered offline by Freezing or Fast Bounce which will result in correct timing regardless of the realtime buffer setting. If you actually have a need to record soft synth audio from existing MIDI in real time for some reasone, you just need to use the lowest possible buffer size, which should always be the case in any real-time recording situation when audio is input monitored through - or originates from within - the box.

 

Thank you, David. I think I understand. This automatic compensation is, well, ...automatic, so we have no need to adjust it, I guess. 

I think I was trying to follow a process that is a standard  procedure in Ableton (recording the met, noting the offset, and setting the compensation manually).  It was mostly out of curiosity that came from following down another path I was on. I am not necessarily having a problem. But when I noticed this, I thought I was having a problem that I didn't know I was having!

It's hard sometimes, not knowing every-bloody-thing like you guys do!  ?

So.... you're saying my above scenario is normal and not cause for concern? 

[David Baay]

Yes, it's normal. I brought it up with the Bakers early on when real-time synth recording was first introduced, and they pointed out that they can't differentially compensate audio generated by existing MIDI vs. live input MIDI when they're in a common stream from the synth.  Since the intent of synth recording was to allow realtime recording from a live MIDI performance the compensation is based on that scenario. 

[John Vere]

As said you will always freeze the midi track to create the audio, No point in running the signal out and back in the digital converters. If what your after is outboard effects then freeze the midi and then loop back the audio, It should be in perfect sync. Always use ASIO for this, all other driver modes won't be in sync. 

[JoseC]

Besides all that, it seems that there is some metronome related malfunction.