Exploring Dynamic Audio Insertion with TED Audio Collective and PRX Dovetail

A deep dive into the “TED Talks Daily” mystery episode and PRX Dovetail

PRX Official
Published in
5 min readSep 13, 2021


At the heart of the PRX Dovetail publishing platform is a dynamic audio stitching tool that seamlessly weaves sponsorship messages to episode segments. Battle-tested with the biggest podcasts in the industry, the platform allows producers to continuously update sponsorship messages on their entire catalog, creating more opportunities to monetize the work they’ve already done.

Dovetail can insert ads at any break within a show and as “bookends” of episode segments. That, plus standard controls like scheduling, prioritizing, and impression capping, offers platform users complete control of how listeners hear ads in their podcasts. Dovetail users can take things up a notch with more sophisticated targeting like:

  • Assigning ads to episodes by topic/keyword, by show, or even to an entire network.
  • Assigning ads based on the age of episodes (only on the latest or back catalog episodes).
  • Finding audience by general location, listening app, or platform while respecting their privacy.

Dovetail’s framework was the foundation for TED’s audio injection approach to increase podcast discovery in the TED Audio Collective. The TED Audio Collective is a collection of podcasts for the curious. They’re for listeners as excited by psychology and design as science and technology — who want to dig deep into today’s most exciting ideas. For those who know TED well, their podcasts will feel familiar but fresh, and those who are new listeners will be introduced to what TED stands for: ideas, not issues. Persuasion and possibility. Optimism and hope. “TED Talks Daily” is one of the largest shows in the TED Audio Collective and already covers interdisciplinary topics as wide-ranging as the collective, making it the natural fit for this experiment. The typical episode structure for a “TED Talks Daily” episode is as such:

Episode Segment: Intro to the TED Talk — Pre-roll Ad — Episode Segment: TED Talk — Post-roll Ad — Episode Segment: Credits

In this traditional structure, Dovetail fills the pre and post-roll slots based on ad inventory that is managed by PRX’s Ad Operations and Sales teams. For this experiment, we wanted Dovetail to fill a single ad spot in a specific episode, bookended by two traditional episode segments that would serve as an intro and outro to the episode. The infrastructure was already there, however, two more things were required to pull it off. The first was to build a special episode structure that had a single ad spot:

Episode Segment: Intro to the episode — Pre-roll Ad: TED Talk — Episode Segment: Credits

The second thing we needed to do was upload a pool of episodes into Dovetail as “ads” so that the platform could choose and insert an episode into the correct slot at random.

The result: “The Mystery Episode,” an installment of “TED Talks Daily” that randomly served different episodes from the TED Audio Collective. Listeners can hear an episode, then check back in later, or on a different app, and might hear something completely different.

TED is constantly looking to rethink the way they engage with their listeners. Through this ‘surprise and delight’ experiment, they wanted to get to the core of what they stand for: broad curiosity and trusted content. In a world with millions of podcasts, searching for the right thing to listen to is difficult, and TED’s goal was to remind listeners that if you’re curious and looking for new perspectives, you can find that across the TED Audio Collective library. PRX was more than happy to execute and examine TED’s exploration using our technology.

Part of the PRX Dovetail publishing platform is a metrics dashboard that presents the audience of an episode by showing all the unique downloads from every platform and player. The Drop Day chart helps producers see how episodes compare to one another in the hours and days following their drop, allowing them to better understand the timing of episode releases.

Using the Drop Day feature, we can see that “The Mystery Episode” had an average number of downloads on its publish day but climbed more quickly than average in the following days. When compared to the eight episodes before and after, “The Mystery Episode” earned 10% more than the average downloads at seven days post drop and had 7% above average at Day 18. We hypothesize that the boost in downloads post-drop day was the result of intrigued listeners downloading the episode multiple times to test the experiment.

There is a noticeable incline in Unique Listeners after April 30th, the day “The Mystery Episode” published for “WorkLife with Adam Grant” and “TED Business”
There is a noticeable incline in Unique Listeners after April 30th, the day “The Mystery Episode” published for “WorkLife with Adam Grant” and “TED Business”

Furthermore, we can make connections when looking for audience transfer from the “TED Talks Daily” mystery episode to other podcasts in the TED Audio Collective. Twenty-two episodes were selected for this experiment from ten TED Audio Collective podcasts. Two of the podcasts whose inserted episodes had the highest impressions — meaning they were heard the most — between April 30th and May 14th did see noticeable inclines in unique listeners in the days after “The Mystery Episode” dropped. Additionally, “TED Talks en Español” had a 15% increase in unique listeners on the episode that was published after April 30th compared to the previous episode.

“The Mystery Episode” is a nice progression in testing Dovetail’s insertion capabilities beyond monetization. What we’ve seen thus far, is that dynamic insertion is not only a great way to experiment with new content, but also a way to repurpose content from the same feed and introduce your audience to new shows altogether. Experiments like these push the way we think about our technology and move the podcast industry forward with fresh experiences for listeners. As more publishers use Dovetail, we’re eager to see what other opportunities arise. Learn more about PRX’s technology at https://www.prx.org/technology.



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