You are listening to a 39MB MP3 file as it was downsampled from the original 32-bit 393MB .wav file, as recorded from Hauptwerk's own direct audio output. The release tails sound somewhat "brittle" as compared to the original .wav file, but this conversion (downsampling and MP3 compression to only 10% of the original file size) was required to upload it to the CBCH.
This performance contains highly stylized registrations with each variation, in order to demonstrate the tonal palette associated with Scots' Rieger. The tempo is played slower than usual, with more rubato to allow one to hear the contrapuntal lines as they interweave between one another. The fugue's tempo is more straightforward and less varied than in the Passacaglia.
This is the audio output with zero post processing/reverb added.