The popularity of the Create an Acapaella in Audacity tutorial prompt an exploration for a similarly free software that could be used as an alternative to Audacity for creating acapellas using the phase cancellation technique.
The free version of Zynewave Podium came naturally to mind. In fact it appears quite useful for this purpose and undoubtedly has some advantages over Audacity.
Perhaps the greatest advantage is the ability to zoom in and out with tremendous ease - and for sample-level alignment, this is a major plus. The inability of Audacity to playback continually whilst carrying out editing tasks is another time-binning irritation in Audacity.
You'll find a useful set of tips for using Podium below.
This tutorial uses Podium Free version 2.37.
Zynewave Podium Free, by default uses, .WAV and .AIFF files - these are the defaults for imports and for exports - if you need to convert your source files - it should be simple to convert to either format in Audacity.
When you start, you need first to create a project and an arrangement. Getting the right settings in the audio tab in the configure audio section of the project, is essential for getting any sound output from Podium.