Bus rendering latency : strange results...

Cubase
1

Hi all,

Well, following this thread : fastest way to convert an item to audio - Cubase - Steinberg Forums , I wanted to test how much latency I was getting between recording a MIDI part and its rendering via the dummy bus way and I got strange results… What I did :

  1. I created an output bus in the VST connection window, not connected and named ‘VST Bus’
  2. I routed a VSTi (True Pianos, here) to the VST Bus
  3. I created an audio track with the VST Bus connected to its input.

On the first case, I record on both tracks, playing few notes with True Pianos, which is like rendering the VSTi to audio as I’m playing it (Cubase_VSTBusRendering_Online.jpg).

On the second one, I render what has been previously recorded in the instrument track, after deleting the previous recorded audio event (Cubase_VSYBusRendering_Offline.jpg).

Could someone explain the rather obvious difference ? :confused:

Not a biggy, but I would like a technical enlightment about this…

Cubase_VSTBusRendering_Online.jpg
Cubase_VSTBusRendering_Online.jpg1920×1200 243 KB

Cubase_VSYBusRendering_Offline.jpg
Cubase_VSYBusRendering_Offline.jpg1920×1200 247 KB

2

Try repeating but with a previously recorded on the beat MIDI track rather than playing live.

3

I’m afraid I don’t understand. You mean, recording something with the Auto Q (transport panel) on ?

4

Well, out of curiosity, I tried with the auto quantize function on with a 1/16th value, just to see…

  1. Whe rendering online, I get all kind of erratic results (even negetive delays), but this is normal, as the auto Q acts just after the record stop, it seems, by positionning notes on the grid. The rendering process has already been done. As a 1/16th interval (tempo 120) is 0.125 s, it explains that sometimes I get delays (positive or negative) of up to 60 ms.

  2. When rendering offline, as the MIDI part is already quantized by the auto Q, I get exactly the same value as the offline rendering of my first post : 3 ms.

The mystery remains…