Podcasting gives me the feeling that I have the keys to NPR; that I can interview anyone I want and then deliver it over the internet to anyone who wants to listen in. Podcasting involves producing your own audio files (usually in MP3, Ogg, or WMA formats) and then publishing them online somewhere, indexed for subscription and reception by an RSS (Really Simple Syndication) reader. They're then downloaded to subscribers' iPods, cellphones, iTunes directories, or other locations to listen to whenever they want. As you'll see, anyone can do this, using all free tools. The podcasting genre particularly shines for interviews. I've interviewed makers from around the world via Skype or iChat (plus in person) and made them available as podcasts. Check out MAKE: Audio on makezine.com for lots of examples.
Conveniently enough, all the applications and utilities I use to create podcasts are free. Here’s what they are and where you can download them.
| Function | Software | Platform | Where to find it | ||
|---|---|---|---|---|---|
| Telephony | Skype |  |
 |
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skype.com |
| iChat/AIM | |
|
apple.com / aol.com | ||
| Audio Stream Routing | VAC | |
ntonyx.com/vac.htm | ||
| Soundflower | |
cycling74.com/products/soundflower.html | |||
| Soundflowerbed (optional) | |
cycling74.com/products/soundflower.html | |||
| LineIn | |
rogueamoeba.com/freebies | |||
| AudioHijack Pro (optional) | |
rogueamoeba.com/audiohijackpro | |||
| Audio Recording / Mixing | Audacity | |
|
|
audacity.sourceforge.net |
| GarageBand | |
apple.com/ilife/garageband | |||
| Encoding | LameLib | |
spaghetticode.org/lame | ||
| LAME | |
mitiok.cjb.net | |||
| Podcast Receiving (called a podder or podcatcher) | iPodder Other apps at ipodder.org/directory/4/ipodderSoftware |
|
|
|
ipodder.sourceforge.net |
Windows
Macintosh
Linux
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Related Reading MAKE: Technology on Your Time Volume 02 |
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On a laptop. If you're just recording yourself or conducting an in-person interview, you can use a laptop and a microphone. You'll need an audio application. If you already have one you like, then great--stick with that. Otherwise, I recommend Audacity, a free, open source, cross-platform audio recording and editing tool. Download Audacity and take some time to familiarize yourself with it. Try recording and importing WAV and MP3 files, and cutting and pasting sections around. Also, see if you like how your microphone sounds.
On a portable device. On the street, an iPod or other small recording device is an even more portable way to capture in-person interviews. I've recorded audio on my iPod using Podzilla (see Mod Your Pod, page 135) and using Griffin's iTalk accessory. If you're an old pro, you're probably already sporting a MiniDisc recorder.
I record most things at 44 kHz, 16-bit stereo, but you can choose lower or higher quality to reduce file size or improve the sound. If you think you might want to save your audio to CD or another "audiophile" format later, record at a higher quality; you can always compress or convert it later.
Using Skype. This free internet telephony application is a great way to conduct remote interviews and conference calls for podcasting (and I use it now for most of my regular phone calls as well). Download, install, and sign into Skype. If your interviewee has done the same, the call is free; otherwise you can pay 2 cents per minute to call their regular phone, anywhere in the world.
Using iChat. On the Mac, you can use iChat instead of Skype, but it only supports conference calls in Mac OS 10.4 (Tiger) and above.
Route the output. Now we need to route Skype or iChat's audio output into our recording application, Audacity. Unfortunately, operating systems still have a hard time routing audio between applications, so we'll need to chain them together with a hodgepodge of platform-specific utilities. Given the variety in sound setups, sound cards, input devices, and recording applications, be prepared for a little trial and error.
Some applications need to be launched before others in order to communicate. Unfortunately, this can vary from system to system. So if this Skype--LineIn--Audacity order doesn't work, exit them all and try some launch order variations.
On the PC (Windows XP), we're also going to use Skype and Audacity. See the On a laptop section for Audacity setup (it's the same for PC and Mac). What's different is how to configure Skype and route its audio. Note that the recipe below, which uses XP's Control Panel/Sound Properties window, works for many systems. But with the PC's zillion possible configurations, sound cards, and audio drivers, your mileage may vary.
Try switching the settings before or during a call, and watch the sound input levels in Audacity to detect when the sound is being routed. You can also use VAC (Virtual Audio Cable), which routes audio from all your devices to Audacity or other sound applications. Check out Virtual Audio Cable at spider.nrcde.ru/music/software/eng/vac.html.
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Once you have your recording, you may want to edit out gaps, remove umms and hmms, and add music or effects. Sound editing is more art than science, and the best way to make a podcast omelet is to break some eggs. Now is also the time to add intro and outro material.
If your interview, music, and other sounds are of different volumes, you should adjust them to even things out. You can do this quickly in Audacity by selecting Edit/Select All and then Effects/Normalize.
Editing and exporting audio on the Mac. Audacity doesn't come with an MP3 converter, because MP3 conversion software can't legally be distributed in free programs. But Audacity and other audio applications can plug in third-party encoders such as LAME.
3a. Download an MP3 codec library, if you haven't already, that works on your platform (see software chart) and extract it to your Audacity folder. Within Audacity, open Preferences/File Format, choose Find Library, and point to the converter. Now you'll be able to save MP3s.
3b. Choose your bit rate in Audacity Preferences/File Format. For voice, I generally use 32 kbps with a sample rate of 22kHz. For a 30-minute segment, I try to keep the files less than 8 megabytes. Experiment with different settings, and keep in mind that many listeners use phones and other devices without much space.
3c. Export your file (or files). Within Audacity, select File/Export as MP3 and/or Export as Ogg. If your audio application can only save WAV files, create the WAV, then use another application to convert via Import/Save As. When Audacity exports an MP3, it will prompt you to fill out the tag information. I usually leave it blank and add it later (see step 4).
4a. Name the file. You can name your file anything (provided you keep the proper extension), but it's considerate to follow a convention that helps listeners find shows in their podcast collections: Show_title-year-month-day.file_extension For example, the MP3 version of MAKE: Audio's June 1, 2005, show would be: MAKE-2005-06-01.mp3
4b. Choose a CC license. A Creative Commons license is a more flexible copyright (a "copyleft") that lets you retain some rights to your works but also encourages sharing, which is what makes podcasts so popular. You can choose a license and find out more at creativecommons.org.
4c. Tag the file. MP3s contain metadata text that you can add to files, such as Song title, Artist, and Genre. Not all players will show these tags, but they're good to add. You can tag an MP3 using many methods, but I use iTunes. To do this, drag the file into the iTunes panel, and then select it and choose File/Get Info. Click the Info tab, and enter the information you want to include. For Comments, you're limited to around 250 characters. I generally list who is on the show, what it's about, and the Creative Commons license. "Podcast" isn't listed in the Genre, but I type it in.
4d. Add artwork (optional). The MP3 format also supports an Artwork tag, which can contain any images you want to include. Most portable players won't display these, but they'll show up in desktop players and on the new color-screen iPod. Adding art increases the file size, however, so you should keep it down to a single JPG or GIF image, 320x240 or smaller. In iTunes, the Artwork tab on the Get Info window you just opened lets you add and delete images.
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5a. Upload the file. At this point, I usually drag the file back out of iTunes to my desktop, and then upload it to my server via FTP. If the show becomes popular, you'll need a server that can handle the traffic, but hosting generally isn't free.
Some podcasters share the load with BitTorrent (bittorrent.com), which is free but not easy to install. Others use Apple's .Mac service, but they've been known to shut off too-popular files. This is a topic we discuss on makezine.com. The important thing is to upload the file to any public server space with a URL you can link to.
5b. Create and publish the RSS feed. The magic of podcasting happens when a podcatcher checks an RSS feed to see if there's a new show. If so, it downloads the show for you to play later. Blogging applications like Movable Type have plug-ins that automatically create an RSS feed, so if you use one of these, it's worth checking for this. Otherwise, here's how you can roll your own in any text or HTML editor. Create a file that looks as shown below (the bold parts are what you change every time you publish a new podcast; the normal text is an RSS template):
<?xml version="1.0" encoding="iso-8859-1"?>
<rss version="2.0">
<channel>
<title>Title of your site</title>
<link>http://www.yourserver/podcast_info_page/</link>
<description>All about your Podcast</description>
<language>en-us</language>
<lastBuildDate>Fri, 01 Jun 2005 08:00:00 +0000</lastBuildDate>
<pubDate>Fri, 01 Jun 2005 08:00:00 +0000</pubDate>
<item>
<title>Title of your podcast.</title>
<description>Show notes and other information.</description>
<enclosure url="http://www.yourserver.com/yourfile.mp3" length="31337707" type="audio/mpeg"/>
</item>
</channel>
</rss>
In the enclosure tag, the URL value is the server location of the file; length is the file size in bytes; and type is the file type and format. Other possible enclosure type values include application/ogg (for Ogg Vorbis), video/mpg, video/quicktime, image/ jpg, and application/x-bittorrent. You can learn more RSS capabilities at blogs.law.harvard.edu/tech/rss. lastBuild and pubDate are the times the feed was last updated and published (for us, the same thing). It's important to keep these up-to-date so podcatcher applications know when you've published something new.
Save this file, in plain text format, with the extension
"xml" (for example, podcast.xml). Then upload
this file to your server. This is the file that tells the
podcatcher apps what you have to offer, and you'll
update it with another <item> section whenever you
publish a new podcast.
If you use GarageBand, you can use the loop browser to create music for your podcasts. I dragged-and-dropped the bongo drum intro for MAKE: Audio from Garage- Band right into the Audacity track. Voilà, a free and easy orchestra.
5c. Create OPML show notes (optional). Outline Processor Markup Language (OPML) is an HTML/ XML relative that's used to create outlines. Some podcasters create notes for their shows in OPML format and upload them alongside the XML, making a richer layer of documentation available to compatible podcatchers. While not a requirement, it's worth checking out at opml.org.
5d. Publish to the web. You're almost a podcaster! Now you need to let the world know about your podcast. There are a few directory sites you can register your podcast on, with more in the works. Start by filling out the forms at audio.weblogs.com, podcastalley.com, and odeo.com.
You've recorded your audio, edited it, compressed, tagged, uploaded, syndicated, and published it. You're a podcaster now. Talk hard--and welcome to the revolution!
The most important part of all comes next: building an audience. Tell people about your podcasts. Participate in the forums on podcast sites. Listen to any audience feedback you receive, and use it to make your podcasts better.
But the surest way you'll develop an audience is through your material. My best advice is to follow the things you're passionate about. If you have a good show and you keep it fresh, people will find you.
The types of podcasts out there are as varied as the web itself. The majority of podcasts tend to be bloggers who use the audio medium to supplement their sites. Podcasts aren't censored, they're not bound by any time limit, and there are no rules.
To get an idea of the more popular podcasts out there, check out my favorite spot: Podcast Alley at podcastalley.com.
You can also see the latest podcasts published from all over the web on audio.weblogs.com. When a podcast is published, the site is usually notified (pinged) and populates the list. If you're ready to listen to your first podcast, then it's now time to grab an application that will do the podcast grabbing for you.
Browse and search podcasts on the same sites where you published yours. Of these, my favorite again is Podcast Alley, which features forums and vote-based rankings.
On the application side, dozens of podder/podcatcher "getters" have been coming out, and most of the ones I've tried work just fine. iPodder.org is a great resource for assessing what's available. My favorite is the iPodder, the standard, which is free, cross-platform, supports BitTorrent, and lets you add podcast feeds from the iPodder.org directory without having to manually cut and paste them in.
Podcasting can be used for any type of file, not just audio. Following the usual succession of tech capabilities, video podcasting (a.k.a. videocasting) is starting to pick up steam, as evidenced with sites like ourmedia.org.
Editor's note: This article was originally published in Volume 2 of Make Magazine. If you'd like to find out more about Make, or how to subscribe to the magazine, go to www.makezine.com. Podcast fans: You can also click here to subscribe to add the Make podcast to your iTunes.
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Illustration by Tim Lillis
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Related Reading Podcasting Hacks |
Phillip Torrone is associate editor of MAKE magazine and producer of MAKE: Audio, all the DIY audio you can shake an iPod at.
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