VST frequency analyzers are kicking in before audio??

I’ve got Fabfilter ProQ, Waves PAZ, and Melda DynamicEQ set up on a VO track. All of their spectrum/freq analyzer’s timings are off though, they kick in about 1 sec before the cursor even hits the waveform. This is bad for me since I’m trying to de-ess, and I cant accurately tell what freq is spiking during an ess.

Ironically, the stock C8 analyzer in Channel Editor/EQ works accurately.

I just switched interfaces to a UH-7000, and am wondering if it’s part of the problem? At first I thought I was having huge output latency issues --but then I noticed that the plugins are just EARLY, and that the audio is not LATE!

Any ideas?


Plugin Delay Compensation in a DAW gets insanely complex, very quickly. The DAWs hide this from us.

There are potentially many different latencies inside the signal path of a DAW due to how plugins are chained, group channels are arranged, and so on.

What you’re seeing with the meters is a glimpse into that machinery. The meters react when they get a signal, which may or may not be when you hear it, or even when other plugins and meters within the project get them (and respond).

It is possible to control this, however, but it’s a moving target every time a new plugin that potentially shifts the latency of the project is added.

What you can do is set up your meters on dummy group channels that terminate and then use Sends (set to 100% pre-fader) to send signals to them. You can then simply power on the Sends of the channels you want to monitor. Sends are good, because they can sometimes short circuit that latency issues, but you’ll have to experiment with where you place the meters.

I think if the dummy channel you put your meters on has no inputs and no output (only what is sent to it via Sends), you should get close to what you want because the vocal channel (that you’ll put your send on) should be hardwired to the meter and therefore in sync.

But that might still be delayed from when you hear it. If so, you may have to add a sound delay plugin (Voxengo makes a free one) before the meters and test some ping signals to calibrate it, to make sure the meters trigger when your hear the sound.


About halfway thru ur message, I remembered that we can sort VST’s by instances in Plugin Manager, and then look at their latencies. I have Waves Z-Noise on a channel, and it’s at a whopping 34,702 (2nd highest was 64)!!

I turned it off (bypass did not work), and my timing was good again. I can of course turn it back on once I’m done freq analyzing.

THANKS for the insight Jalcide…I don’t use Z-Noise that often, I’ll have to remember this :slight_smile:

Good news! Just in time for the long weekend.

But you should report this behaviour to FabFilter as they don’t synchronize their user interface to the audio signal properly. If they don’t know about it, they won’t fix it. And it’s their job to do it right :wink:


It’s not a bug, because it’s not technically possible.

Plugins report their internal latency to the host, not the other way around. So there is no way for a plugin to know by how much to delay their meter graphics to match the downstream PDC.

Having a plugin know about the total PDC on the DAW’s output, or even the PDC at the plugin’s own scope, is not part of the VST, AU, etc. spec.

The workaround is to monitor the signal where the meter is, somehow. Or to bounce the audio into a low latency project where metering is responsive.

I haven’t tested this, but the Ext effect plugin in Cubase should allow a signal to appear on an audio interface’s outputs immediately (like a “tap” into a line), where it could then be monitored, free of any downstream PDC introduced latency (which should then be in sync with the meters on that channel).

This is wrong, part of the VST2.x and the VST3 spec is the possibility for a plug-in to know when it’s audio will be heard:
For VST3 lookup the documentation for IAudioPresentationLatency.

This is used by the Channel-EQ in Cubase to make sure that the display is in sync with the audio.


Thanks for the reply, Arne.

Is this a recent part of the spec? Or is it DAW dependent?

It seems to be 3.1.0 version of the VST spec, only.

Also, the spec appears to require a “busIndex” for which to return the latency? Is it possible to obtain the bus index responsible with outputting the sound? Is that something all DAWs support?

I’m just trying to understand why we don’t we see this being used more often?

Even the Waves Dorrough meters do not appear to honor it.

Thanks for your insight. I have more than a passing curiosity, as I’m considering the development of VST plugin as part of a visualization product I’m working on. I’ve always thought this was not possible.