Creating Ethical Society of St. Louis's podcasts

Folks have asked how I create the Ethical Society of St. Louis’s podcasts. There are countless ways to create podcasts and no right or wrong answers for this question. In all of these approaches there are three required components. 1) You need to get the audio on to a computer (initial capture), 2) edit it to create a file that can be used as a podcast (audio processing), and 3) set up the mechanism that lets users hear or subscribe to your podcasts (RSS feed creation). Having no budget and using readily available free software, I developed processes for each of these components that work for me.

Initial capture: I capture our platform presentations direct to digital. I do this by plugging an output from our sound system into the computer’s microphone jack using a cable from Radio Shack. The recording software I use is HarddiskOgg (http://www.fridgesoft.de/harddiskogg.php) which is installed on an older notebook computer (Windows XP, IBM ThinkPad X30, Pentium III M 1200MHz, 512MB Ram). Using this direct link I record the platform address to a WAV file (sample rate 44100 Hz in mono). While the resulting file is large (300 to 400mb), it is a lossless format ideal for later editing. Note that, because of copyright restrictions, I do not record the musical selections performed before or after the address. If I happen to get them I will edit them out before in the next step.

Audio processing: This component is the most time consuming part of the process and involves multiple steps. First, using an inexpensive computer microphone, I record the podcast’s intro and closing. I then import these two files and the platform recording into a new project in our audio editing software. I use Audacity (http://audacity.sourceforge.net) for all of our audio editing. The hardware requirements for this software are quite modest and I use a older desktop computer (Windows 2000 Server, Pentium 1000MHz, 512MB RAM, with a sound card) for these tasks.

In Audacity, I trim the unneeded beginnings and ends off of the three recordings and arrange them to flow together in the correct order (my intro, the platform address, and my closing). I adjust for volume differences between open/close and platform (effect/amplify with default settings) and compress the dynamic range (effect/compress with default settings). Compression reduces the differences between the presentation’s quiet are loud parts which makes it easier for a listener to adjust their volume to a comfortable level. I also fade out during the applause at the end of the platform (select the audio to fade and effect/fadeout). Once all of this is finished,I export the edited audio tracks to an MP3 file. As part of the export process each file is tagged using the ID3v2 tag format with:

  • Title: Title of the presentation
  • Artist: Speaker, Agency
  • Album: Ethical Society of St. Louis
  • Year: Presentation year
  • Comments: Platform presentation from the Ethical Society of St. Louis (d-MMM-yy)

The last audio processing step is to apply the final compression and filtering to make the file small enough to be easily downloaded (at least for users with a fast internet connection or lots of time). Using LAME (http://www.mp3dev.org/), I process the file exported from Audacity to make sure that it is mono, resample it (input 44.1 kHz output 22.05 kHz) and apply a lowpass filter (transition band: 7557 Hz – 7824 Hz) to remove frequencies that are not important for speech. I finally upload the LAME processed file, which at this point is between 7 and 8 MB, to our web server noting the final file size (this information will be added to the RSS feed).

RSS feed creation: An RSS feed is simply an XML file in a very particular format. There are a variety of free programs that will create the appropriate file structure. Because I develop using Microsoft products I chose Raccoom (http://www.codeproject.com/csharp/rssframework.asp). You can easily find many others (http://www.google.com/search?q=rss+feed+creator). For my part I used Raccoom to create the RSS file for the first half dozen or so platforms. However, much of the information I needed to enter was very similar from program to program and it became tedious to enter it afresh each time. So I started editing my feed in Notepad. I would copy a previous platform, paste it into the file and edit it appropriately. I found this approach to be much faster. (However, it is important to check the feed after you put it on the web to make sure that everything is correct. I usually manage to make at least one mistake that warrants correction.)

The final point is how the web page which presents our podcasts http://ethicalstl.org/libraryaudio.shtml (and the RSS links) is created. Our server supports PHP so I incorporated a free PHP script from a company named FeedForAll (http://www.feedforall.com/free-php-script.htm) into our page. This page and script lists the available podcasts using the information from the RSS feed. So I enter the information once into the RSS feed and it is used by aggregators and on our web pages.

So what are the costs and benefits? Once I have the initial platform recording, the whole process takes 30 to 60 minutes. So the software is free. The computers needed are relatively low powered. The only real investment is in time. As for the benefits I will share just one. We got an email from a person living in the south who was attending their local church. They said

I feel like I cannot, for family reasons, attend and become a part of the "Ethical Culture" movement at this point in my life but I really get so much out of being a "virtual" member of your society.  I just wanted to say thank you for what you do and to let you know that your podcast is really making a difference, and even to those like me that are attending "traditional" churches.

What more could I ask?