You can't hear a digital filter? How about a digital filter which removes all frequencies above 1khz, or a digital filter which compresses 70db of dynamic range down to 40db? While those filters themselves may be technically "inaudible", everyone can certainly hear the results of those filters.You can’t “hear” a digital filter. The filter removes the hiss and replaces it with nothing. All you hear is the original dialogue, and it sounds natural.
plektret's concern was over wording used in the advertising of this disc. As RAH correctly noted, Warner typically does a good job with audio, so with any luck this particular disc will be fine. But this disc aside, the concern over audio manipulation is perfectly valid. Just as there are limits to how much film grain can be removed without loosing visual detail, there are limits to how much audio "noise" can be removed without loosing audible details.
This is an important and fascinating subject which deserves it’s own thread. As most of these posts have nothing to do with Maltese Falcon, it would be wonderful if they were ported over to a new thread.
Fortunately so far, no one has complained about the audio on this release.