Beyond Traditional Broadcast
For most of the twentieth century, the idea of broadcasting audio came from traditional sources such as radio or television. These formats used FCC licensed airwaves, and later purchased cable services, to send out a signal that a large cross section of the public received. Today, the term may not refer to this at all but rather using Internet technology to broadcast to a much more specific group. Beyond the audience, it is also fundamentally different. It is often a cohesive audio track rather than a live broadcast. Because of this, you will notice much of what you take into account when preparing one of these broadcasts is different from the more traditional formats.
Today, the formats for digital audio broadcasting usually fall between exclusively talk and exclusively music. When you are working with purely music tracks, mastering the final track is easier since the files already exist in their final version. The main item to identify is the highest possible audio track you can work with. You will usually want to avoid more compressed MP3 files and go for a WAV file instead. If you do not have a direct access to the source files, you might not have many options. You cannot convert an MP3 file to WAV since it will already have the quality loss. When you do have the files you may want to just stack them together onto a timeline-based audio mixing program and intersplice this will talk periods introducing or commenting on the music content.
Talk radio, which dominates audio podcasting, works differently. First, you are responsible for producing the audio that you are working with. At the same time, you usually are using less than professional equipment to do this. Because you can go back and mix the audio of the downloaded recorded track, you have more opportunity for this method than live types. In this situation, your main goal is the clarity of people speaking. If you use outside sounds or audio snippets then you will likely try to add them during the mix so that you have control over their quality rather than play them during the actual recording.
Go beyond your computer's microphone when recording sound or dialogue used in a digital audio broadcast. Your computer may not have the capacity for a full audio range or maintain the kind of quality needed to sustain an audience. When creating a podcast or streaming radio program centered on talking, get the cleanest and fullest sound you can, which means attaching an outside microphone to your computer.
Since you will be indoors and have a reasonable amount of control over the recording situation, choose quality and sensitivity over rugged durability. A condenser microphone may be best, but if you have to record outdoors with weather interference, you may want to go for some type of dynamic microphone.
Maintain sound quality as much as possible when preparing your final mix for digital audio broadcasting outlets. This means observing the same rules for export that you would use when importing audio. Use uncompressed modes that allow for the least amount of loss and the largest audio file type. The actual place that is hosting your audio podcast or streaming radio will have its own requirements that must be observed, such as the distribution mode made with iTunes, so you need to use those limitations as your base requirements. You always need create as fundamentally large a file as you will be relegated to.
This does not mean that you have to worry too greatly about loss, however. The majority of people listening to these broadcasts, especially with audio podcasting, will be on low quality playback tools. Whether these are low-end speakers or iPod headphones, they are not going to give much of a difference if there is minor loss.
Source: Author's own experience.