Audio FX delay compensation

cold ones wrote on 2/5/2012, 2:41 PM
When I use the more CPU-intensive settings for iZotope RX 2 Denoiser it applies delay compensation so the audio stays in synch with the video (you can tell it's working because the little green FX icon turns gold when in playback).

This works well as a Track FX. However, when I apply the same FX to a bus or event the icon stays green and the delay compensation does not work. Is this a rule? Do busses & events not do delay compensation, or is there a way to make them work?

<edit>
It's actually a bit odder than noted above: when I apply the FX to a bus, the icon IS gold if you click View:Audio Bus Tracks and view the bus on the timeline. (I was viewing the bus in the Mixing Console, which does not turn gold.) However, no matter how you view it, the audio is really late when the FX is applied to the bus. (This is also true of the Master Bus when viewed outside the Mixing Console, except that in this case the FX icon stays gold all the time, even when the project is NOT in playback.)

I can't find any way to apply these FX to bus or master and get the benefits of delay compensation, however.

Comments

TheHappyFriar wrote on 2/5/2012, 3:58 PM
I do remember that since Vegas 3 (when I started using) this was the reason all audio FX applied to the event were rendered and that there were specific track & up audio FX, so stuff like this didn't happen.

Is it a delay before the FX kicks in or a delay before any audio at all kicks in?
cold ones wrote on 2/5/2012, 4:43 PM
It's a delay that results from the time it takes the audio FX to work, and then play out the affected audio. The delay compensation is supposed to help Vegas synch it up, but it seems to be hit-or-miss.

It's nice to have real-time non-destructive FX, but the iZotope FX seems to take a lot of resources. Also, iZotope has a 4 different algorithms you can choose from, which take increasing amounts of CPU effort. Heaven help me, I've tried to apply the lowest-impact algorithm to two different tracks, and this compounds the problem. (If I render out the audio, it seems okay, however). If I reduce the quality level, things play better. That's why I was trying to apply it at the bus level, so there was only one instance of the FX.

Geoff_Wood wrote on 2/5/2012, 4:52 PM
Denoising is not the sort of process that I would not attempt to do in real-time, not on multi-tracks at once, even less likely on a Master Bus, and never-ever on an Bus FX !

As well as typically being CPU intensive and invoking higher processing latencies, it is the sort of thing that a highly-focussed individually tuned approach is required for each individual event, rather that a 'broad blanket approach'.

geoff
cold ones wrote on 2/6/2012, 11:05 AM
Geoff, I agree with you in principle---

In this case I'm working with dialog recorded in a moving vehicle. What I've done is route these (ducked) tracks to a Bus and then apply the denoising to the mix of both. I like it because it allows me to adjust the denoising in a central location.

I can see the logic in what you're saying---and if I apply the FX to the track I get the correct delay compensation. The problem for me is that the more challenging algorithms in RX2 won't play in realtime, so I can't use them during editing. When I render out I've got to remember to change out the FX settings, and if they're in too many places I tend to miss them.
TheHappyFriar wrote on 2/6/2012, 12:32 PM
This is a case where the scalpel called "Sound Forge" would come in to play. This is something it's designed for.