The branding of this whole thing is quite confusing - since the upsampling is one piece, the apodizing filter the other. In this case, i'm fairly certain Dolby just wants to push 96 kHz as the standard in playback from their perspective. The PDF below is pretty well written when it comes to explaining pre-ringing: http://www.amr-audio.co.uk/large_image/Tech%20Paper%203%20-%20Ringing.pdf Suffice to say, it's not below the threshold of our perception. While we may not "hear" pre-ringing on its own - the effect it has on our perception of the impulse as a whole is negative. Dolby has some very bright PhD's with psychoacoustics specializations working on this and other projects, and there is a lot of research out there indicating this is a real phenomenon. For my part - I was able to tell the difference in their tests, even with every intention of hearing nothing it wasn't subtle on certain recordings, mostly the orchestral samples.