A while back I was having trouble getting my audio input level to remain constant. It turns out that the problem was with Skype.
I do video interviews via Skype and other services on my MacBook Pro. Since interviews contain multiple audio sources, if my audio input doesn’t stay constant, it creates a big mess. I’ve gotten most of the bugs out of the system (See Remove hiss in audio recordings, What I use: online meeting and podcasting audio setup) but the biggest issue was this wandering, mostly diminishing audio input volume.
For reference, here are my System Preferences:As you can see, I’ve chosen an input level for the iMic device (connected to my mixing board and mic) but even though I could set the input volume here, it would still wander downward. Even worse, when setting the input volume, I could watch the slider slide downward (Ironic, no?) when it recognized silence in the room.
The Guilty Party: Skype Auto Adjust
Skype has their own set of audio and video preferences and most sound like they can defer to the current system settings. In the screenshot below, you can see that I have chosen a specific microphone input, but deferred to the system settings for ringtone and speaker settings. While I could have also chosen Same as System for the microphone as well, I regularly disconnect my laptop. I have discovered that upon reconnect, the system tends to revert the audio input (mic) setting back to the laptop mic input.
In particular, note the Automatically adjust microphone settings check box. This is just ambiguous enough to sound like a good idea, but when selected (in my case) it gently pushes the volume down to an unacceptable level, even when the Skype preferences are not open.
The bottom line
When using Skype or other software to record audio, make sure that any auto settings are disabled and manually adjust the inputs to appropriate levels. And of course, always test record your equipment before interviews or running an online recording session.