Video Transcript
KS Series: Cardioid Solutions
4m 35s
00:05
Subwoofers can be great for creating that big gut-punching concert sound
00:09
that a lot of artists and musicians want.
00:12
They can also help bring clarity to your PA
00:14
by taking on the burden of reproducing power-hungry low frequencies,
00:17
allowing the rest of the system to perform more efficiently.
00:21
However, subwoofers can also come with a few unwanted side-effects.
00:25
Unlike high frequencies, which are very directional, subwoofers radiate energy in all directions
00:31
around the entire enclosure.
00:33
This can lead to undesirable low-frequency build-up on the stage or DJ booth
00:37
and wasted energy around the sides and rear of the system,
00:40
which can often lead to issues like feedback or loss of intelligibility.
00:44
Additionally, if a subwoofer is placed near a wall or in a corner,
00:48
the reflections from these surfaces will most certainly lead to low-frequency cancellations.
00:53
This creates dips and holes in the low-end,
00:55
making the overall dispersion pattern inconsistent throughout the listening area;
00:58
leading to an unpleasant experience for the audience.
01:01
By utilizing what’s known as a cardioid subwoofer configuration,
01:05
you can “focus” the low-end radiation and give your entire system the directionality it needs,
01:10
cleaning up the low-frequency build-up on stage and keeping your PA system sounding musical
01:14
and intelligible for both the audience AND the performers.
01:18
Being able to direct the low-frequency can also be handy
01:21
when trying to keep your neighbors happy.
01:23
Traditional cardioid subwoofer deployments are created using an array of individual boxes.
01:28
In the simplest cardioid setup, you put two subs together either next to, or on top of each other,
01:34
with one of them facing backwards.
01:36
You heard that right.
01:37
Backwards.
01:38
Then, by using appropriate adjustments of the phase, delay, frequency, and gain alignment on both units,
01:45
the resulting pattern of the subwoofer array will become cardioid
01:49
and cancel out most of the low frequencies that are radiating toward the back.
01:53
How, you ask?
01:54
Because physics.
02:00
In this video we will demonstrate 3 ways to quickly and easily setup a cardioid configuration
02:06
using two KS118 active subwoofers.
02:09
One of the great features of the KS118 is the factory Cardioid Preset.
02:14
This Preset instantly takes care of all the adjustments needed
02:17
to set phase, delay, frequency and gain.
02:20
You don’t have to worry about all the math and the extra equipment it would take
02:23
to otherwise do it yourself.
02:25
The first deployment we’ll look at is a side-by-side configuration.
02:29
In this deployment, the two subs are placed side-by-side facing opposite directions.
02:34
Make the proper connections to your PA system
02:36
and then select the correct “Cardioid” preset on each of the KS118s.
02:39
On the front firing sub, select the CARDIOID FORWARD Preset
02:43
and on the rear-firing sub select CARDIOID REAR.
02:45
That’s it!
02:46
The presets will apply phase cancellation, correct gain and time alignment to the subwoofer array
02:51
and effectively create around 15 dB of low-frequency rejection behind it.
02:56
It’s pretty dramatic when you hear it in action.
02:58
If you have the vertical space available, you can use our second deployment
03:02
which is to stack the subs on top of one another, with the top cabinet pointed toward the audience,
03:07
for a an improved cardioid pattern.
03:09
In the last configuration, we’re going to position the subwoofers back-to-back.
03:14
This of course requires more horizontal depth, as the rear-firing sub will be directly behind
03:19
the front-firing one.
03:21
This setup will yield the best results out of the 3.
03:23
The time alignment in the Preset is perfectly optimized for this configuration,
03:27
which provides the highest amount of rejection in the back of the array.
03:31
Not only that
03:32
but the rejected energy in the back of the array will also help push more energy forward,
03:36
increasing the intensity of the low end towards the audience.
03:39
For smaller venues or events that may not require the might of two 18-inch subwoofers,
03:45
but could still benefit from directionality in the low end, we have the KS212C.
03:50
This is a best-in-class single enclosure cardioid subwoofer solution,
03:54
powered by a 3,600 Watt Class D amplifier and processed with the latest DSP technology.
04:01
It features two 12-inch long-excursion drivers, one forward and one rear-firing -
04:07
each arranged in a 6th order bandpass chamber.
04:10
These components all combine seamlessly to produce 15 dB less output at the rear of the enclosure.
04:16
If you’d like to know more about these KS Series subwoofers or how to set up cardioid arrays,
04:20
you can find further detailed information in our Application Guides and User Manuals
04:25
at qsc.com.
04:26
Thanks for watching.
04:27
We’ll see you next time.
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KS Series: Cardioid Solutions
4m 35s