Search Issue Tracker

Fixed in 2020.1



Found in







Issue ID




"Assertion failed on expression" error is thrown when Audio Group's "Send level" variable of "Send" effect is exposed



How to reproduce:
1. Open attached project ""
2. Open "Audio Mixer" window
3. In Project Window select "MisterMixer"
4. In Audio Mixer window, select "Sender Group"
5. In Inspector window, right-click on "Send level" and expose the value
6. Observe the Console window

Expected result: the value is exposed, no errors are thrown
Actual result: "Assertion failed on expression: 'm_ExposedParameterCache.size() == GetMixerConstant()->exposedParameterCount'" is thrown

Reproducible with: 2017.4.32f1, 2018.4.7f1, 2019.2.3f1, 2019.3.0b1, 2020.1.0a1

Comments (2)

  1. Dbe865348965dce994407c6dae59936d?d=mm


    Dec 18, 2019 18:55

    Hmmh, at the moment, in order to have "real" send level control from code, using exposed mixer parameters, I guess one could first insert a stationary always-on-100%-send that sends into a separate dummy track, then expose the attenuation parameter on that extra track - and then, in turn, send downstream from there into the actual desired send target. Control the exposed attenuation parameter from code to effectively get dynamic send level control. It does get a bit messy if you have a lot of groups and stuff to send, but at least it works for now.

  2. Dbe865348965dce994407c6dae59936d?d=mm


    Dec 18, 2019 18:29

    Is there a way to work around this, or is this currently stopping exposing Send levels altogether?

    Just bumped into this when getting to know the Unity Mixer, trying to access Send levels from code, via exposing them first in the Inspector. As this error happens, I can't dynamically vary the Send level of something being sent to a Duck Volume effect, for example, or adjust signal levels for echo/reverb sends at runtime, and such?

Add comment

Log in to post comment

All about bugs

View bugs we have successfully reproduced, and vote for the bugs you want to see fixed most urgently.