I record my lectures via USB microphone. I use one of these:
http://amzn.to/1AsaEip It is a bit pricey, but I have not found anything close at a reasonable price to capture excellent audio. It will only capture my voice, though. I also have one of these that I occasionally use:
http://amzn.to/1tofv1F With this one I'll plug it into my computer and use it as a USB mic. My classrooms have array mics in them as well, but I found the audio to be so noisy as to be unusable.
When I was using these devices with Windows 7, I had to make no adjustments at all. With Windows 8.1 on my SP3 I did have to make changes as the first couple of recordings I made were so low in volume it was hard to hear. I simply plugged the device in, and then went down to the system tray and right clicked on the speaker icon and chose Recording Devices. From there I found the device I was using and viewed its properties. On the Levels Tab I maxed out the slider. Problem solved.
I record my lectures and desktop using Camtasia, but the audio capture adjustments above should help with any audio capture software.
I see now that the OP is not the lecturer. I'd still recommend making the audio adjustments noted above to see if it improves the volume of the capture.
