# Listening for subaudible tones

**URL:** <https://community.wowza.com/t/listening-for-subaudible-tones/632>\
**Category:** Wowza Streaming Engine\
**Created:** [November 13, 2014, 1:46pm UTC](https://community.wowza.com/t/listening-for-subaudible-tones/632 "2014-11-13T13:46:24Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![system](https://sea2.discourse-cdn.com/flex002/user_avatar/community.wowza.com/system/32/447_2.png) [@system](https://community.wowza.com/u/system)\
**Post date:** [November 13, 2014, 1:46pm UTC](https://community.wowza.com/t/listening-for-subaudible-tones/632/1 "2014-11-13T13:46:24Z")

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We have RTMP streams that we are transcoding in Wowza Streaming Engine that have local and legal ad breaks with 25 and 35 hertz tones embedded in the streams. Is there a way to set up a listener within Wowza to detect when one of these tones has been played?

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**Author:** ![Paul\_Shields](https://sea2.discourse-cdn.com/flex002/user_avatar/community.wowza.com/paul_shields/32/390_2.png) [@Paul\_Shields](https://community.wowza.com/u/Paul_Shields)\
**Post date:** [November 14, 2014, 4:22pm UTC](https://community.wowza.com/t/listening-for-subaudible-tones/632/2 "2014-11-14T16:22:11Z")

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Hi,

We don’t have anything that can detect frequencies in that way. I would think you would need to write a custom module to perform frequency analysis of the audio track. If you need assistance in that area you could ask at our [Find a Consultant](http://community.wowza.com/c/-/7;tabid=70) forum.

Paul