First of all - I'm not saying there's anything WRONG with having two subs. It may make placement (which is the REAL issue people should focus on with subwoofers) easier in some rooms. And yes, I did have two smaller 12" Velodynes before I sold them to go with a single larger one, which I keep in a slightly off center position - not in a corner.
The reason you have the potential for multiple subs for movies is because some DVD's may place bass tracks in multiple locations - intentionally WAY out of phase for FX purposes - not for music. You can hear that because two sub channels may be mixed 90 degrees apart. But we (at least I) haven't been talking about DVD/Home theater, which I have no interest in. Perhaps I should have been more specific.
As people have said above, the STEREO location of a piano, for your example, even at the 27.5hz Low A comes from the ample myriad of higher pitched overtones that ONLY arrive through the mains. Good subwoofers (if set up properly) playing NORMALLY recorded music, especially on LP - which is all I listen to - are fed no recognizable stereo information through the crossover to transmit. It isn't there unless intentionally placed by the engineer using digital delay effects - like done in a DVD.
In a true musical stereo recording, the pure bass frequencies cannot arrive at the mics far enough out of phase to be audibly placed - only the overtones can. Even in what is called an "exaggerated separation"/ "ping pong" effect by engineers, 2 stereo mics are placed maybe 10 feet apart with a 3rd one in the center. Even assuming the lows aren't later panned to the center during mixing (which they are), the TRUE bass might be out of phase enough to jump a needle from the groove, but still not enough for you to guess where it's coming from.
re: "Both subs responded at different times depending on who was playing. Apparently there are recordings with the lowest notes in stereo on some cds." Or, as you said earlier, "I can put my hands on each driver simultaneously and feel them vibrate at different times on the same tracks."
- - - - Of course you can! Nobody said the recorded signals to both channels are identical - but that doesn't at all mean if you had your eyes closed (and didn't already know the music) you could point to where the bass is coming from.
Anyway, I give up on this one... there's no argument that defeats the Magic Ear theory.
re: Bumblebee flight
From Straightdope.com:
"The basic principles of bumblebee flight, and insect flight generally, have been pretty well understood for many years. Somehow, though, the idea that bees "violate aerodynamic theory" got EMBEDDED IN FOLKLORE."
From David Wilkinson of Quarksoft:
"bringing two wings flat against each other and then moving them apart, very strong vortices were produced which could generate unexpectedly large lift. The earlier "disproof" was based on an inadequate model but THE STORY HAS AN INSTANT AND LASTING ATTRACTION TO THE NON-TECHNICAL MIND."
'Nuff Said.
The reason you have the potential for multiple subs for movies is because some DVD's may place bass tracks in multiple locations - intentionally WAY out of phase for FX purposes - not for music. You can hear that because two sub channels may be mixed 90 degrees apart. But we (at least I) haven't been talking about DVD/Home theater, which I have no interest in. Perhaps I should have been more specific.
As people have said above, the STEREO location of a piano, for your example, even at the 27.5hz Low A comes from the ample myriad of higher pitched overtones that ONLY arrive through the mains. Good subwoofers (if set up properly) playing NORMALLY recorded music, especially on LP - which is all I listen to - are fed no recognizable stereo information through the crossover to transmit. It isn't there unless intentionally placed by the engineer using digital delay effects - like done in a DVD.
In a true musical stereo recording, the pure bass frequencies cannot arrive at the mics far enough out of phase to be audibly placed - only the overtones can. Even in what is called an "exaggerated separation"/ "ping pong" effect by engineers, 2 stereo mics are placed maybe 10 feet apart with a 3rd one in the center. Even assuming the lows aren't later panned to the center during mixing (which they are), the TRUE bass might be out of phase enough to jump a needle from the groove, but still not enough for you to guess where it's coming from.
re: "Both subs responded at different times depending on who was playing. Apparently there are recordings with the lowest notes in stereo on some cds." Or, as you said earlier, "I can put my hands on each driver simultaneously and feel them vibrate at different times on the same tracks."
- - - - Of course you can! Nobody said the recorded signals to both channels are identical - but that doesn't at all mean if you had your eyes closed (and didn't already know the music) you could point to where the bass is coming from.
Anyway, I give up on this one... there's no argument that defeats the Magic Ear theory.
re: Bumblebee flight
From Straightdope.com:
"The basic principles of bumblebee flight, and insect flight generally, have been pretty well understood for many years. Somehow, though, the idea that bees "violate aerodynamic theory" got EMBEDDED IN FOLKLORE."
From David Wilkinson of Quarksoft:
"bringing two wings flat against each other and then moving them apart, very strong vortices were produced which could generate unexpectedly large lift. The earlier "disproof" was based on an inadequate model but THE STORY HAS AN INSTANT AND LASTING ATTRACTION TO THE NON-TECHNICAL MIND."
'Nuff Said.