# VST3 WaveLab 9 Elements Sidechain Issue no processBlock + Reason

**URL:** https://forum.juce.com/t/vst3-wavelab-9-elements-sidechain-issue-no-processblock-reason/20092
**Category:** Audio Plugins
**Created:** [November 30, 2016, 1:18pm UTC](https://forum.juce.com/t/vst3-wavelab-9-elements-sidechain-issue-no-processblock-reason/20092 "2016-11-30T13:18:26Z")
**Posts on this page:** 2
**Page:** 1

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### Author: ![chkn](https://sea2.discourse-cdn.com/flex026/user_avatar/forum.juce.com/chkn/32/3862_2.png) [@chkn](https://forum.juce.com/u/chkn)
#### Post date: [November 30, 2016, 1:18pm UTC](https://forum.juce.com/t/vst3-wavelab-9-elements-sidechain-issue-no-processblock-reason/20092/1 "2016-11-30T13:18:26Z")

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VST3 Plugins with Sidechain in WaveLab 9 Elements, processBlock isn’t called  
(latest tip from develop)

In the VST3 Wrapper:

The reason is totalInputChans == 2 and pluginInstance-\>getTotalNumInputChannels() == 3  
so processBlock isn’t called

(maybe other hosts have the same problem, so better add dummy buffers, if not enough channel-buffers are provided…?)

```
  if (totalInputChans == pluginInstance->getTotalNumInputChannels()
         && totalOutputChans == pluginInstance->getTotalNumOutputChannels())
        {
            if (isBypassed())
                pluginInstance->processBlockBypassed (buffer, midiBuffer);
            else
                pluginInstance->processBlock (buffer, midiBuffer);
        }
```

---

<div class="post-metadata">

### Author: ![fr810](https://sea2.discourse-cdn.com/flex026/user_avatar/forum.juce.com/fr810/32/841_2.png) [@fr810](https://forum.juce.com/u/fr810)
#### Post date: [December 2, 2016, 10:53am UTC](https://forum.juce.com/t/vst3-wavelab-9-elements-sidechain-issue-no-processblock-reason/20092/2 "2016-12-02T10:53:36Z")

</div>

Arggghh… yet another WaveLab workaround. Anyways, it’s fixed on develop.