# Fetting Stereo Difference from 2 audio inputs?

**URL:** <https://www.ruby-forum.com/t/fetting-stereo-difference-from-2-audio-inputs/240715>\
**Category:** GNU Radio\
**Created:** [April 27, 2014, 1:12am UTC](https://www.ruby-forum.com/t/fetting-stereo-difference-from-2-audio-inputs/240715 "2014-04-27T01:12:40Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![Detlef\_R](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/58f4c7/32.png) [@Detlef\_R](https://www.ruby-forum.com/u/Detlef_R)\
**Post date:** [April 27, 2014, 1:12am UTC](https://www.ruby-forum.com/t/fetting-stereo-difference-from-2-audio-inputs/240715/1 "2014-04-27T01:12:40Z")

</div>

Here’s an odd problem I’m having; I am attempting to get the stereo  
difference of two audio inputs from JACK, (Each connected to the L or R  
channel)

[AUDIO IN “L”] - \> Subtract |\_  
[AUDIO IN “R”] - \> Subtract |

What I get however, is summed channels with some reverb. Same for adding  
the two inputs. As GNURadio does not allow JACK to have 2-channel  
input,  
this is the only way I can get Stereo audio into the graph.

Perhaps there is a patch out there to fix that? Anyone have luck with  
this?