Originally Posted by Nigel Goodwin:
“From your claim that subs produce directional audio, in which case the sub would need to be sited in the correct place - which would need to be specified on every individual film.”
To clarify.....
.1 channel can produce frequencies around 250Hz downwards, not just non directional frequencies.
A system consisting of 5 main speakers capable of producing 50Hz, 1 sub that goes down to 20Hz. You set the xover to 80Hz, then everything from 80Hz and below gets sent to the sub. The frequencies from the sub will be non directional, but that doesn't mean you can stick it anywhere in the room, there are other factors to consider, because the wavelengths are long things like reflections, furnishings, standing waves can affect the bass response in the room.
The advantage if its in line of sight you won't be able to tell where the bass comes from.
A system consisting of 5 satellite speakers capable of only producing 130Hz, 1 sub that goes down to 20Hz. You set the xover to 130-140Hz, everything from 130-140Hz and below is sent to the sub, then the sub will be producing directional frequencies, best option is to place out of site, if in sight you will be able to tell where the frequencies are coming from, so again, thought and care is needed in positioning the sub, you can't just plonk it anywhere.
Originally Posted by Nigel Goodwin:
“I agreed a LONG time back that there are limitations on where you might site a sub, but it has nothing to do with any imagined directional properties - only with the physics of fitting speakers close to walls or not.”
You gave the impression that sub positioning was of minor importance because of the nature of its nondirectional frequencies.