Originally Posted by mastermaybe
I'd be interested to hear the drawbacks of such a feature
Some I mentioned previously, some I haven't:
You would lose your HPF protection on the analog multi-channel inputs (on the vast majority of AVRs, maybe all but one?);
You would lose the ability to use infrasonic devices (buttkickers, etc.);
The vast majority of subs typically used already have a HPF (if they need one). So in most cases, you'd be double-filtering (which is considered bad practice) and you could end up losing extension unnecessarily;
It would be an imprecise method, because Audyssey wouldn't know whether or not the sub NEEDED a HPF. Does the sub have one (or doesn't need one), and the -3db point is the natural intended rolloff, or is it an unprotected ported sub that should be rolled off aggressively from that point? Sealed subs typically roll off at 12db/octave, while ported subs should typically be rolled off around 24db/octave (or other values for other alignments). How much of the rolloff curve is due to the sub, and how much is offset by room gain? How would Audyssey know what rolloff curve (if any) is appropriate?
... especially considering that a decent sum looking into high end apps of Audyssey XT 32 may very well have passive subs and amps that are not so easily configured to accomplish the goal.
Me being the type that "enjoys textual combat", I'd argue that point.
If you look through the "Subwoofers, Bass, and Transducers" forum, I think you would find that very few have subs that need a HPF, but don't have one. Earlier you indicated that a DSP with the appropriate filters can be had for $50 (I don't know, I've not searched for them). If so, I would suggest that anyone looking in to a high end passive sub that needs a HPF would much prefer one that could be tuned to the specific needs of that sub, rather than letting Audyssey guess at what it should be. Is it really worth all the potential negatives to save $50 on (what I perceive to be) a very small percentage of applications?
It it were done as a feature that could be turned on of off, then many of those negatives would go away. But my opinion is, that function is best served by the subwoofer circuit, and therefore there would be little value in "marketability" of that feature from Audyssey's perspective, especially considering the additional liability they'd be taking on.