I have downloaded the latest version of Audacity primarily to make ‘live’ single track, single take, stereo recordings from the piano. I have tried all combinations from the 4 options in the drop down menus for recordings but the result is the same: the signal is strong but after a few seconds there is a noticeable ‘dip’ or ‘phasing’ effect resulting in a playback which sounds ‘tinny’ & goes ‘in & out of focus’. I’m sure there is a straightforward explanation which eludes me?
Windows thinks you’re trying to make a conference call and is suppressing any sustained sounds – like music.
Koz
The rely from Steve has completely resolved the problem thanks. 
(Not sure about the conference call reference however?) 
I have subsequently discovered that nearly all of the aforementioned ‘worble’ was not a record issue at all, but due to the incorrect equalization (presumably too much boost to low frequencies) being applied in playback. If I playback with ‘classical’ equalization or ‘none’ it sounds fine…any other setting is a disaster! 
