While we usually recommend utilising metadata triggers for programmatic ad injection, we understand that this does not fit into every station's playout workflow and, therefore, an alternative solution is required. As such, we accommodate inaudible tone triggers, which can be played out on your stream and trigger the ad injection system via audio detection rather than metadata.

The service detects subaudible 18Hz, stereo-inverted tones of a predetermined length. When audio matching this is played out on your stream (i.e. the subaudible audio file is queued up at the start of your break), the programmatic ads will begin to inject, either conforming to the fixed length of your insertion configuration or to the length of a replacement window (signified by a second subaudible tone at the end of your break).

In this guide, we'll walk you through the steps to effectively use these tones for ad triggers in your internet radio station.

Steps Overview


Step 1: Download 18Hz stereo inverted tones

To get started, download and extract the files from the SharpStream_StereoInverted18HzBeeps.zip folder attached to this article. These tones will serve as markers for the start and end of your ad windows.

Step 2: Insert tones into your broadcast

During your broadcast, insert the 18Hz stereo inverted tones into the audio stream at the designated points. These tones act as triggers for your programmatic ads. Place them at the beginning and end of commercial breaks or at specific intervals within your content.

If using midroll replacements, bookend your predetermined ad window in your playout system with the start and stop tones. 

If you are using midroll insertion, you only need to add a singular tone file at the point you want the ads to start inserting.

Not sure which injection method you use? Read our article here for help: What's the difference between insertion and replacement, and which one should I choose?

Step 3: Confirm with our support team

When you have completed the above steps, let the SharpStream support team know so we can implement the setup on the ad injection service. Ensure the break intervals and lengths match the predetermined ad preferences so we can ensure a smooth programmatic ad injection experience. 

Step 4: Monitor and adjust

As the trigger is baked into the audio, latency between metadata and audio reaching the stream isn't an issue. That said, there may be some latency in response time from the ad injection server, in which case a start/stop shift may need to be applied to ensure your ads are triggered bang on time.

Step 5: Automatic ad playback

When the detection software identifies the inaudible tone marking the start of an ad window, it will automatically trigger the playback of your programmatic ads. These ads are delivered based on listener data, enhancing personalisation.