The Interactive Advertising Bureau is testing the podcast marketing waters with a special fall upfront featuring 20-minute presentations from digital audio's big guns.

AdLarge, Midroll, NPR, Panoply, Podtrac and WNYC will present to an audience at an IAB Podcast Upfront Showcase, where select advertisers and media buyers will be able to preview "the latest in innovative podcast programming" from the networks, according to the IAB.

"The whole point of the event is to test the market," said Carl Kalapesi, VP of industry initiatives, IAB. "We know there's a lot of interest."

Interest in podcast advertising has bubbled since last year's premiere of "Serial," the record-setting podcast whose MailChimp audio ads became a bit of a sensation. Podcasters and others are still working out kinks in the ad model, though, in an effort to broaden the format's appeal to marketers. The IAB released a digital audio buyer's guide in April, developed by its digital audio committee, aiming to set ad standards.

Momentum is hot, though, so why not debut the upfront alongside the spring TV upfronts and IAB's digital video-focused NewFronts? NPR, WNYC and WBEZ put on a podcast upfront in April, while IHeartMedia pitched advertisers on podcasts at a "Soundfront" the same month.

The Podcast Upfront Showcase just happened to work out with the IAB digital audio committee's calendar for early September, said Mr. Kalapesi, adding that the upfront's podcast partners had talked for a while about organizing a broad event to educate marketers, showcase content and bring the podcast industry together.

Podcast presenters include companies responsible for "Serial," "Freakonomics Radio," "Planet Money," "Slate's Political Gabfest," "TED Radio Hour," "This American Life" and "WTF with Marc Maron."

The showcase will be held Sept. 10 at the Jerome L. Greene Performance Space in Manhattan.