This month, we’re going to explore the inner depths of postproduction. This often misunderstood black art of buffing and sheening your recordings is essential in producing high quality output. The postproduction process doesn’t simply involve levelling your mics, but also includes subtle effects and processing that can improve sound quality. With good postproduction techniques, your show can be dragged up from an amateur-sounding effort to a properly produced, professional-sounding masterpiece.

Tooling up
Postproduction generally involves three processes: mixing, adding postproduction effects/dynamics and mastering. Each of these processes can be conducted with your sound-editing tool, but in the case of more limited tools, you may need to use another utility for some of these processes. In this issue, we’ll predominantly use Steinberg Cubase SX to produce a simple radio show.

The first step is to lay your recorded content and musical interludes on separate tracks. It’s always advised that you keep different types of content on separate tracks. For example, you may have a single recorded track with two or three vocal mics on one track (this is fine), but keep any additional musical breaks or third party clips (such as pre-recorded material or adverts) on separate tracks. This gives you the ability to apply postproduction to different types of content on a track-by-track basis. Place your content on the different tracks in the right order. Don’t worry about accuracy at the moment. At this point, you should get a good idea of how the show is ordered, so ensure you adjust the order of your content until you’re happy with it.

Expanding tracks
The next step is to start at the beginning of the track and to stitch the different sections together. This process will involve accurately placing the clips together and adjusting the different volume levels so they sit well together. Most sound-editing programs include a ‘zoom’ tool that you can use to accurately place the second clip after the first one.

When the clips are placed, you should adjust the volume. The vast majority of editors include some form of volume control that you can apply throughout the track. Here, we’re not interested in a volume for the entire track; we want finer grained control to adjust the volume in different parts of the same track. In Cubase, this functionality is available by expanding the track you’re working on. In the expanded part of the track, you’ll see a line running throughout. You can use the ‘pencil’ tool to draw a point on this line and then use the hand tool to move the point up or down. The higher the point, the higher the volume. Most tools include a means to control volume by adjusting the position of points.

Dynamic scrubbing
The process of going through each of your clips, placing them in the right order and adjusting the volume levels, is an essential yet time-consuming process. When this is complete, the next step is to place any additional clips and overdubs into your project until all the raw material is complete.

Dynamics is the postproduction work that scrubs up the quality of your audio to emphasise the right audio frequencies. This typically involves two dynamics: compression and limiting. Of these, compression is next on the list for us to apply. Many editors include support for dynamic effects in VST form on Windows [ click here ], or LADSPA form on Linux. You can apply the effect by adding it inside the mixer window or by right-clicking a track and adding the effect.

The compression effect makes louder sounds more level and the quieter sounds louder. This results in an even balance in which the different voices can be heard more clearly. Compression is a hugely complex subject and we don’t have the space to cover it here, but there are usually presets that get you started. Look out for a ‘Vocal’ preset in the compression or dynamics part of your editor.

Limiting loudness
Next, we can apply some ‘limiting’ to the volume of your track. One of the biggest risks associated with any kind of vocal recording is the fact that you’ll have some people talking quietly on the mic and some talking much louder. If you’re feeding each of these different mics into a mixing desk and recording to a single track, there’s a risk that you may make the volume louder to hear the quieter people and make the louder people so loud that their voice distorts.

The solution to this problem is to apply limiting to the track. This effect will simply ensure that the audio isn’t allowed to rise above a certain setting, most typically 0dB. This will ensure that the audio remains at a volume that music players can handle. You should never have any audio louder than your limiting setting. To apply limiting, you can normally add it in the ‘effects’ part of your editor, or in the mixing section. You shouldn’t add limiting to music unless the music is too loud. It’s always better to simply adjust music with your normal mixer faders.

Mastering
With your audio mixed, it’s time to master it. The mastering process can involve its own degree of audio processing, but this kind of processing is redundant in a grass roots Internet radio show. What’s important is to ensure that people can download your show and listen to it easily. Mastering all your tracks down to a single audio file is simple, and is often referred to as ‘mixing down’. In this process, your final audio file is likely to be saved as a large WAV file. When you’ve saved this file, you can convert it into the different formats that you may want to distribute. Any show you create should be made available in MP3 and Ogg format. To perform the conversion, you can use either lame on Linux to create MP3s or oggenc on Linux to create Oggs. On Windows, you can use WinLame for both formats.

Distribution
You’re now ready to release it to the world. To do this, you should ensure that you create a podcast feed to enable people to use podcasting software to pick the file up. In addition to this, you should make the files generally available on a website. It’s likely that your MP3 and Ogg files are large, and if you have a limited amount of bandwidth with your ISP, the download count may outstrip your bandwidth limit. You should explore other methods of distributing your files, such as using mirrors or bittorrent .

In this series, we’ve explored the different processes of creating an online radio show. You’re now set to join the burgeoning revolution that’s setting MP3 players across the world ablaze with shows and podcasts. Good luck with your show, and don’t forget to let us know how you get on!