Originally Posted by bossobass
Yes, Josh, but I've been down this road before. I've posted FRs from every seat, separately and averaged, smoothed and non-smoothed. I've posted FRs during every step of the anechoic vs in-room with signal shaping to bridge them after placement, phase, delay and levels tweaks. I wrote a setup guide based on all of that.
Guess what? No one cares. They seem to prefer to hang on to the Magic Room theory, or that some silly gadget will do all of that for you, as long as you have 4 subwoofers.
I would as well. Or, as I mentioned earlier in the thread, a stack plus a spread across the wall. Or anything real from actual posters' situations, really, anything but this Harman infomercial stuff.
I should head your way and we can spend a day trying the Harman white papers stuff vs whatever else approach and post the results for "peer review".
I see several people being correct here.
JBL ignores the z-axis for a very simple reason that bosso pointed out: they have no products that would fit the situation. While JBL/Harman does have some of the most complete documentation and information out there, they are still a for-profit enterprise, and don't think that any author's work is not looked at carefully by other JBL folks before it is published.
The theory behind the Welti/Devantier method is sound. Their process has many holes in it, unfortunately. Do you think that 'audience box' started out that small? HELL NO (or at least, probably not). But by making it smaller, they got to report better results.
The theory of the Geddes method is similar. But it also is flawed. Seriously, run a pink noise RTA/Spec Analyzer and wave a mic around to see what your freq response is doing 'in the listening area'? GTFO.
The best way to do a room setup is use some theory to help guide initial placements, then verify with measurement, modify placement/bass trapping/delays/eq/etc, verify again, and continue the iterative process until you reach nirvana or simply say 'good enough'.
All of the 'theories' and 'methods' are complete and total BS unless verified by measurement IN THE LISTENING SPACE IN QUESTION. There is no such thing as an 'average room'.
If you truly had a rectangular room with reflective/absoprtive capability the exact same for all 4 walls, ceiling and floor (what Welti and Devantier assume in their simulations), then eight subs, placed at the 1/4 points in all axes would be ideal. You cancel EVERY odd axial room mode and the first even room mode on every orthogonal axis. Second best would be to give up the 2nd mode cancellation in the z-axis and bury the subs in floor and ceiling at the 1/4 points.