I'm told it's a problem with the filenames, which were prepared on a Mac and which aren't readable by some Windows systems (though strangely I had no problem on my own...), which cause some files not to show or not to open. Anyway, we're re-naming and re-uploading so that they work. Apologies again for any inconvenience.
According to the article in the mag that I have in front of me now, 1a and 1b are of a dry vocal with a fixed tempo; the file 1a should be the vocal alone, whereas 1b adds a metronome so that you can 'hear' the tempo. Example 2 should have the delay on it. But if I'm missing something here, do let me know!
SOS Reviews Editor