Better Sound with SnapzProX

When recording a screen movie, e.g., a software tutorial, with SnapzProX, you can choose to record a voice-over with either the built-in or an external microphone. The problem is that the sound quality is not very satisfying given that it is a straight recording. It would be better if you could filter that audio recording in real-time. The solution comes through Soundflower and Audio Hijack Pro.

I happen to already have a license of Audio Hijack Pro (AHP), but I am sure this would also work with Ambrosia’s WireTap. You need to have Soundflower installed before you start. In AHP, this can be done conveniently via Install Extras… from its program menu. Here’s how to set it up:

1. Go to the OS X audio system preferences and select Soundflower (2ch) as the input source and Internal speakers as the output source. Then mute your internal speakers. Note: as a shortcut to the audio settings, type Option+one of the three volume keys.
2. In AHP, create a new entry and select either the built-in microphone or your audio interface as the input device, and Soundflower (2ch) as the output device.
3. Click on Advanced… and choose your microphone input channel for both left and right input. Choose channels 1 & 2 for the output. That way, the mono microphone will be heard on both the left and the right speaker in your headphones and recording.
4. Next set up your audio filters. I like to use a noise gate filter to remove background noise and a little bit of reverb.
5. Now hijack the audio stream and set up your screen for recording your tutorial.
6. In SnapzProX, after selecting to record a movie, also click the box next to Microphone Track. Do not select the Mac Audio track.
7. To monitor your audio recording, the best option is to use latency-free monitoring with your audio interface if you have one (If not, then connect your headphones to the Mac and unmute it; the associated delay will be quite long. I find it too distracting to be useful.). Using latency-free monitoring you will hear the raw audio, not the filtered signal. To monitor the filtered signal, you can add an an Auxiliary Device Output to AHP’s Effect’s patch and set it up to route the audio to your audio interface (This will add a tiny bit of delay, but I find it not distracting).

Here’s what this does. When recording your movie, Audio Hijack will capture your microphone input, pass the signal through your audio filters and then pass it on to Soundflower. The microphone sound will be provided by the Soundflower channel, because that is how we set it up in the system preferences. SnapzProX in turn will take that microphone sound and record it with your movie.