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Originally Posted by
deedeeyeah
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not quite...
these measurements (rta as you correctly mentioned) stem from three different locations of which only one uses a line array - also, most subwoofer arrays are designed in a way that they become rather directional at whatever frequency; of course the lower one goes, the more difficult it gets - the idea that one hears just the output of a single directive horn in a specific position when using a line array is flawed.
nothing else going on here either and no way on earth someone is cutting the lows this much: on the contrary, most system these days get aligned with a 6-10dB bass bump (unfortunately)!
please note that as mentioned previously, these screenshots are no measurements of the systems with pink noise on but what the actual response of the music looks like; measurement responses of the systems with pink noise would indeed look way more flat, depending on distance and alignment. nevertheless, roll off starts almost always clearly below 10kHz, certainly for music reproduction: i usually go for a curve that is close to the old b&k curve (or the whatever the headliner's tech wants me to dial in).
for comparison, here's a screenshot from a measurement (fft in this case) of a system which i re-installed last summer, in a venue that mostly houses classical music (and for which the system doesn't get used at all) but also modern music and jazz which was taken into consideration when designing, positioning and aligning the system (which is fairly large/uses a multitude of speakers, both arrays and point source speakers, fills, delay lines, subs etc.)
Did you really leave the system like that? Were they happy with it?
I hope I'm not coming across as a jerk, I'm just baffled by seeing that curve. I design and tune installed systems and would never ever leave a system looking/sounding like that. Yes, sometimes clients want 6db of sub tilt below 100hz. But to not correct the rest of the range, especially the low-mid summation build-up and at least some of the air absorption (which is that sharp roll-off at 14k you have)... I can't imagine that system is anywhere near sounding its best.
The correlation trace is abysmal too, which makes me think either the measurement is not being done properly, or is way off-axis of the speakers, or the space is incredibly reverberant, or something in the system is straight-up broken. Given the correlation trace, you can't rely on any part of the measurement being accurate other than the 150hz region. Where is the signal in time, in the impulse measurement up top? It should appear as a single point in time, plus or minus a couple distinct later reflections. Instead there is a cacophony of noise. It looks like SMAART probably couldn't even find the correct delay value.
As for the frequency response, like I said, line arrays or other multi-element systems often start out looking something like this. But they cannot be left in that state. It would sound horribly muddy and exacerbate any room build-up. You said "no way on earth someone is cutting the lows this much" but I promise you it happens every day on professional systems. Such cuts are almost always built in to multi-element presets in system processors. Processors are designed to be used to cut that much of the lows in multi-element installations.
Have a look -- here is the default EQ curve that Meyer uses for a 4-box Mina array at 100ft distance with 100% atmospheric correction (which is the 16Khz bump *only*). This is what they know will bring 4 boxes flat in an anechoic environment - and each individual box starts already flat in the nearfield by itself. The curve needs to get even more extreme if you add above 4 boxes, and also is not accounting for any kind of room response yet. EQ curves bigger than this are being used every day on systems everywhere.