Ready for some podcasting tips? Ready to make your podcast sound great?

In my last post, I wrote about some of the first steps to take when you are ready to make your podcast sound more like the professional podcasts you listen to.

We started with the two most essential factors in audio quality: the space you are recording in and your microphone. Now, we will move on to the software.

Software can only do so much to make your podcast sound better.

As I mentioned in my last post, software does its best work when you are starting with a good, clean audio signal. That is why starting with the initial recording is so important. Any noise, reverberation, or other room sounds will end up in your digital recording. Any deficiencies in your microphone will also show up in the recording.

While software can help to mitigate audio issues, there is only so much it can do. In some situations, efforts to reduce noise and echo tend to make the whole thing sound worse.

For this series, I am going to assume that you already know how to record sound and do some basic editing in your software of choice. It won't matter which software you are using because these concepts are the same no matter which platform you choose. However, I will use examples from some of the more popular options: Audacity, Adobe Audition, and Garage Band.

Compression, limiting, normalization, and equalization

In this series, we will look at three aspects of audio production: compression, limiting, normalization, and equalization. Used together and correctly, these can make a considerable improvement in the sound of your podcast. Today, we will examine compression.

Compression - In the audio world, compression is the process of reducing the dynamic range of an audio file. In more straightforward English, it reduces the difference between the loudest sounds and the softest sounds in your recording. It does this by lowering the level of the loudest sounds and boosting the level of the quietest sounds. If you have ever listened to a recording that caused you to keep your hand on the volume to turn it up when you couldn't hear and turn it down when it was too loud, you heard a recording that needed compression.

Two roles of compression

In a podcast, compression has two critical roles. The most important task is keeping the volume consistent throughout the episode. Listeners don't want to have to pull their phone out of their pocket to change the volume constantly through your show. The second role is crucial if you use music in your podcast. Shrinking the dynamic range of your vocal audio makes it easier to mix your vocals with music without having to continually adjust the music.

Let's listen to an example.

I recorded that in the built-in Garage Band app and turned off the built-in compression and reverb. Let's see what this looks like. We will take a look in Adobe Audition's audio editor.

You can see the significant differences in the dynamic range. Next, I will put some compression on it. If you only remember one thing about compression, remember not to use too much. In layman's terms, it will make your podcast sound bad.

When applying compression, in most software programs you will find some presets. If you don't want to learn about how compression works, you may find one that does the trick. But, just for fun, let's look at how it works.

Threshold, Ratio, Attack, and Release.

There are four main factors in compression: threshold, ratio, attack, and release.

Threshold & Ratio

Threshold is the level at which the compressor starts doing its job. In other words, how loud does the sound need to get before it needs to be reduced?

Ratio is about how much we are going to lower the level once it surpasses the threshold. This starts to get into math, so I am going to attempt to simplify. The higher the ratio, the more you will be compressing (or reducing) the sounds that are louder than the threshold you set. A 1:1 ratio wouldn't have any impact. A 20:1 ratio would act more like a limiter not allowing much of anything to go past the threshold.

If you want to get a good sound out of compression, you are going to need to experiment with the threshold and ratio. Back in the day, when I learned, compressors were big, rack-mounted components with knobs.  I found it easier to experiment on those, but the new digital plug-ins give you much more power and flexibility.

Attack & Release

Attack and release are a lot simpler to understand but just as important and just as tricky to master. Attack refers to how fast the compressor kicks in when the signal crosses the threshold. Release is just the opposite. How fast does the compressor release the signal after it goes back below the threshold? The fundamental rule of thumb is that you want this to be as fast as possible without causing any distortion. Again it is about experimentation and careful listening. Let's look again at our audio clip now with some compression.

See how those levels are more consistent across the track? You will also see (and hear in a moment) how that background noise, breaths, and other sounds have also been increased. We Will deal with that in another post.

Let's listen.

Now, as an example, I am going to put way too much compression on the track.

Take a look.

Now take a listen.

The toughest thing about compression is that you need to trust your ears. This is where listening to other podcasts helps. Have a listen to a couple of podcasts that sound really good to your ears. Then, start experimenting with compression settings that make your show sound better.

And, this is just one step. In the next post, I will examine limiting and normalization. Once we have the compression right, these will help us get our levels set correctly.