:: Ultra Music Festival ::
The PA consisted of flown d&b J8/J12 (no J-Subs), and (16x)
BASSMAXX X2C “Deuces” lined up across the stage.
The sub line was long enough to get some serious pattern control outside the edges, and in fact this is what we
wanted in order to avoid spill to the extent possible in other
areas. With this many systems, and this much sub content,
any control available is gladly exercised. So a quick alignment
job on Bayfront consisted of sub alignment via phase trace to
the flown PA, some quick EQ on the PA (the d&b systems
seem to never need much, particularly outdoors), and some
sweetening by ear on the subs. A 6 dB low shelf boost on the
Deuces suggested by Dr. Bassenstein was applied, and after a
little experimentation using the Lake Contour controller we
liked what we heard.
WORTH NOTING
Our efforts were concentrated on
integrating the center BASSMAXX
stack with the spread CSA B2 stacks
residing under each side of the PA.
The lack of a tech day meant that forklifts and lulls were
constantly working everywhere. At one point on Bayfront I
had my back turned to the stage trying to figure out what was
going with this crazy transfer function that could not possibly
be right, noise running at a fairly high level. I turned around
and a lull had pulled up next to my measurement microphone,
completely contaminating the measurement. It turned out this
would be the rule, and not the exception, the rest of the day.
Back To The Main Stage
The amp rack for the center BASSMAXX array eventually
arrived and we began. The first set of measurements was
mostly on axis with the house right portion. Using the multi-channel capacity of SysTune, it was quite easy to quickly
switch between measurement microphones. Additionally,
the easy management of overlays helped me move quickly
between tasks.
Since we were short on time, our efforts were concentrated
on integrating the center BASSMAXX stack with the spread
CSA B2 stacks residing under each side of the PA.
The following screen shot is of a measurement overlay taken
on site, and reloaded back into Sys Tune after the fact. The measurements were done with a 64K FF T size, yielding 1. 46 Hz
frequency resolution. This resolution is OK for low frequency
work but is too fine for HF work. Also, the delay offset and
measurement levels do not affect the loaded overlays. Savvy
users will notice the “zero” delay time – this is because we’re
looking at reloaded overlays, not live measurements.
The previous measurement is of only the steered-out B2s,
taken from the center of the audience area. The next step is
to add the BASSMAXX cluster in the center:
Keep in mind here we have steered the outside B2’s away
from the center a bit to allow the BASSMAXX boxes to have
some of their own space. We have not adjusted the gain on
the center sub array at this point. Listening tests validated
our original notion that if they sound different enough, we
should avoid overlap if possible, and these subs definitely do
not sound “the same,” whatever that means.
So in our center position, the B2’s began to drop off just
below 40 Hz as seen in the screen shot. The BASSMAXX
subs remained quite flat to 30 Hz. The phase angles are mostly
matched, if not perfectly timed at the measurement position.
However, after listening we decided to treat the BASSMAXX
array separately and Rosenstock inserted an 18 dB octave low
pass filter at 47 Hz (after some experimentation), and this
