Originally Posted by Bill Fitzmaurice
As for sub stacking, you'll get a better result spreading them about the room. Stacking subs gets higher output, but does nothing to address room modes. Vertically stacking cabs does have a major benefit when the stack is at least 3 wavelengths high. At 100Hz that's 33 feet; at 20Hz it's 170 feet.
Sorry Bill, theorizing is one thing, but this ^^^ is just nonsense. Show your data.
Vertically stacking eliminates the floor-to-ceiling standing wave and incorporates the ceiling as a 4th virtual primary point source.
One sub in a corner vs a stack of the same sub in the same corner. Mic position is unchanged. The traces are normalized to show the difference in FR because the output increase is a given.
You go from (+/-) 21dB to (+/-) 8dB and, with a single PEQ filter you're at (+/-) 3dB. You're welcome to lug the 4 modules all over the room based on a) where your rooms layout will actually allow you to physically place them in the room, b) your latest mathematical guru-inspired theory, c) trial and error or d) a combination of all of the above. But, to state categorically that stacking is not a viable option tells me you have no evidence from the real world.
Having extremely accurate measurement capability, you would then compare the digits on a full bandwidth disc to the mic'd version from the listening position. The following is a scene from HTTYD when the big dragon bursts out of the cave, captured straight off the player and mic'd at the LP.
If it gets better than that ^^^, please post the data.
Getting back to the topic, Arch mentioned GTGs as a metric for benchmark, or subjective preference, or whatever anyone would like to call it. Since there really is next to zero objective data used to explain the preferences at a GTG, I, after following one of those threads, took the FR data posted and created a Spectrograph of one of the scenes listened to at the GTG and made a simple comparison showing what the participants actually heard from the SM vs a Cap sub:
I've posted countless times that ULF does not have to be 145dB (or whatever the Equal Loudness Curve graph and similar opinions theoretically dictate it 'needs' to be) to be heard, felt, sensed, etc. When there is a +20dB difference from one presentation to the next and a +4dB difference at the center frequency, every listener will notice the difference and the majority will judge it to be 'better'.
If there were digital vs mic'd version spectrographs of the scenes presented at a GTG (the digital versions could be done in advance and the mic'd versions done at the GTG), one would be able to see the distortions presented to the listeners.
Playing "What if?", what if the SM gives 100% THD at 8 Hz and it's mostly 2HD? That 16 Hz 2HD would add impact at a frequency where the other subs have no output at all and at a frequency where there is no content in the soundtrack. There are many more variables that decrease the value of the subjective opinions of listeners when there is no data to help explain those preferences and opinions.
So, hats off to Seaton for designing his sub to use the room (and that would be any room the sub is placed in) to allow owners to experience another octave. I've said so many, many, many times since the SM hit the streets. But, the 'benchmark' is a combination of hard numbers data resulting from a rigorous regimen executed by an extremely capable young man. You simply can't dismiss that data because some guys liked the sub better than a couple of other subs, excluding the current benchmark subs.
IOW, the SM either gets included in Josh's Data-Bass, or no benchmark for it. Once it's been tested and the results are included, then you can see if there is a correlation between "everyone liked it best at the GTG, so it must be a benchmark" and the actual numbers. It's my opinion that there will be, but my opinion is just that. Folks who place their opinions above the data... well, good luck with that.