# Plugin Downmix

**URL:** https://qa.fmod.com/t/plugin-downmix/12133
**Category:** FMOD Engine
**Created:** [November 3, 2015, 7:32pm UTC](https://qa.fmod.com/t/plugin-downmix/12133 "2015-11-03T19:32:56Z")
**Posts on this page:** 2
**Page:** 1

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### Author: ![rsabi](https://avatars.discourse-cdn.com/v4/letter/r/5f9b8f/32.png) [@rsabi](https://qa.fmod.com/u/rsabi)
#### Post date: [November 3, 2015, 7:32pm UTC](https://qa.fmod.com/t/plugin-downmix/12133/1 "2015-11-03T19:32:56Z")

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I noticed the FMOD Channel Mix effect is able to take in multiple channels and down mix it to a user specified number of channels, how would I go about writing plugin that takes a signal and down mixes it?

Thank!

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### Author: ![rsabi](https://avatars.discourse-cdn.com/v4/letter/r/5f9b8f/32.png) [@rsabi](https://qa.fmod.com/u/rsabi)
#### Post date: [November 3, 2015, 10:28pm UTC](https://qa.fmod.com/t/plugin-downmix/12133/2 "2015-11-03T22:28:21Z")

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To answer my own question, a good example that does this is the fmod\_distance\_filter plugin. Look at the callback FMOD\_DistanceFilter\_dspprocess