# An issue about the built-in convolution\_reverb DSP unit

**URL:** <https://qa.fmod.com/t/an-issue-about-the-built-in-convolution-reverb-dsp-unit/14368>\
**Category:** FMOD Engine\
**Created:** [February 14, 2019, 2:15pm UTC](https://qa.fmod.com/t/an-issue-about-the-built-in-convolution-reverb-dsp-unit/14368 "2019-02-14T14:15:00Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![nyanchan](https://avatars.discourse-cdn.com/v4/letter/n/9dc877/32.png) [@nyanchan](https://qa.fmod.com/u/nyanchan)\
**Post date:** [February 14, 2019, 2:15pm UTC](https://qa.fmod.com/t/an-issue-about-the-built-in-convolution-reverb-dsp-unit/14368/1 "2019-02-14T14:15:00Z")

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Hello.  
When using FMOD’s built-in convolution reverb unit, the input file seems to be heard as if it was rendered as mono. If I combine the same input and IR on DAW (Reaper + ReaVerb), the stereo image is preserved.  
I don’t know which is the “right” behavior, but I want the processed output to be heard like the one I did on my DAW.  
Is there any way that I can change FMOD’s current behavior in this situation?

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**Author:** ![richard\_simms](https://yyz2.discourse-cdn.com/flex036/user_avatar/qa.fmod.com/richard_simms/32/261_2.png) [@richard\_simms](https://qa.fmod.com/u/richard_simms)\
**Post date:** [February 14, 2019, 11:27pm UTC](https://qa.fmod.com/t/an-issue-about-the-built-in-convolution-reverb-dsp-unit/14368/2 "2019-02-14T23:27:32Z")

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On the Convolution Reverb effect there should be a button underneath “Channels” called “Link”. Make sure this is disabled otherwise the convolution reverb will mix down all channels into mono.

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**Author:** ![nyanchan](https://avatars.discourse-cdn.com/v4/letter/n/9dc877/32.png) [@nyanchan](https://qa.fmod.com/u/nyanchan)\
**Post date:** [February 15, 2019, 3:33am UTC](https://qa.fmod.com/t/an-issue-about-the-built-in-convolution-reverb-dsp-unit/14368/3 "2019-02-15T03:33:46Z")

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Thanks, it worked!  
I’m experimenting with several reverb algorithms, and I’ve just got another question. I’ll post it as a separate topic since it’s not related to convolution.

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**Author:** ![richard\_simms](https://yyz2.discourse-cdn.com/flex036/user_avatar/qa.fmod.com/richard_simms/32/261_2.png) [@richard\_simms](https://qa.fmod.com/u/richard_simms)\
**Post date:** [February 15, 2019, 3:45am UTC](https://qa.fmod.com/t/an-issue-about-the-built-in-convolution-reverb-dsp-unit/14368/4 "2019-02-15T03:45:55Z")

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No problem, I’m happy it helped! 😃