all right my name is Dave brat and I'm going to talk about real-world
subwoofer setups implementing them for live shows different designs that are
involved some basic background behind the various designs and
for those of you who don't know who I am I've been mixing Red Hot Chili Peppers for 20 years
I mix Sound garden blink-182 the three bands that most recently been working for I designed
quite a few sound system subwoofer systems over the years and started a sound company about 30
years ago called rat sound that rents equipment internationally for large scale events I'm in
the fortunate position to where I not only see these speaker designs from a design angle and
have designed built constructed and rented them out but also I get to mix on these configurations
listen to them and see what they how they perform in real-world environments and I get a chance to
mix on multiple systems all over the world as I travel with various bands I get to see the
different setups and configurations that are people that people are using and I preferences
and issues with different configurations in order to talk about subs there's three different
parameters that should be looked at coverage which is you know because is it an omnidirectional sub
look a double 18 is horn loaded sub it's fairly directional right off the right off
the bat what's its vertical coverage not only the horizontal covered with the vertical coverage of
the individual and or the sub-array multiple enclosures that are involved feasibility you
know if you have a sub it sounds great and covers well but it's too big to be fit to fit in the door
of the venue or if your sub setup is extremely effective with it that blocks the sight lines
and/or it pushes the barricade so far from the band that the audience is disconnected
or you get a bunch of bleed on the stage you know there's various issues that feasibility
issues with the setups and then finally sound quality what is the sub set up sound like and
there's a lot of prediction patterns which will tell you what the sub will do coverage wise they
don't really indicate what the sub set up would sound like and some of these sub setups that
are being that are being used today sound a lot better than others and there's some significant
issues with some of the setups so being a fairly complex concept my daughter Sammy and I made some
Lego subs actually made a Lego sub array here we use later on the hinges and stuff so I'm going
to cover the various basic types of single box subs most common currently is a double
18 double 21 15 or just a direct rating you see the speaker's right in the front for the most
part at low frequencies these enclosures have close to a omnidirectional pattern which means
they cover all the way around about the same volume maybe they're a little quieter behind
but for the most part there's mommy directional it's important to realize that this pattern is
not only limited to the horizontal plane but it also involves a vertical plane so wherever you
are the same distance from this speaker about a piece of strength should be approximately
the same volume horn loaded cups you know if yourself it's got a speaker in the back of
bunch of speakers there they tend to naturally be directional both in the vertical and horizontal
plane I'm not going to get into those very much because they're not very they're not as common
anymore and not as useful for setting up these arrays depending on the interaction between
the subs in order to achieve the coverage patterns of another type of stand-alone sub
would be a directional sub ricardio tub and there's basically four different methods of
achieving pattern control other than the horn-loaded out of a subwoofer enclosure
probably the simplest one is to have some speakers let's say you have two speakers pointed forward
and also have two speakers pointed backwards in the enclosure the sound from the back speakers
would be radiated first the front speakers would be on a time delay and the measurement
they would do some measurements in the design of the speaker so they measure the time it takes the
sounds that come out of the back of the speaker come around the box and pass the front speakers
and right when it's reaching that point the front speakers within radiates sound and it would be an
additive summation in the fluid axis and since this front speakers are radiating later and
there's a distance they have to wrap around the sound coming out of the front speakers wrapping
around would not be in time of the speakers in the rear causing a subtractive or cancellation
behind and that will give you some cancellation behind and addition in the front another method
of doing this would be to take the rear speaker and reverse polarity on it have speak the south
in this one the time delays are reversed you would have to sound radiate it out of
the front speakers first and the sound that wraps around the back as it comes to the rear the rear
speaker would radiate sound but since it's out of polarity it would cancel out the sound that
wrapped around from the front and Douce the volume behind now this is more effective at
cancelling sound behind but the downside of that is sound from the rear speaker also wraps around
front and causes interference with the front speakers reducing volume and causing some less
than desirable sonic issues in the forward rate eating area so they tend to be less efficient
you're wasting some power there you lose a little volume you lose a little sound quality but you
gain improved rejection behind the box that design there has two other similar offshoots the both of
the first two require two separate amplifier channels and a delay on one of those amplifier
channels and possibly some processing in order to achieve its coverage there are some passive
versions of cardioid subs where they've taken the sound of the rear and created some chambering or
the way the enclosures built basically acts the mechanical time delay and maybe there's
a port in the back that radiates some sound so the sound from the front is canceled out
by the sound radiated at the rear port and a very similar design of that would be to have the rear
panel of the speaker cabinet be non-rigid have some vibration to it flexes either rallying a
channel in there putting some silicon the weight of that the size of that and how well attached
that is would determine the volume and frequency at which that resonates that could be that can be
tuned to cause a cancellation behind the box of some of the energy from inside the box would come
around and cancel and cause a cardioid pattern again a single F channel no profit no processor
required solution to creating a single enclosure cardioid some for the most part I'm going to lump
all those together into a single entity and just call them a single box cardioid sub for the rest
the course of this I try and stay away from the ones that have the out of polarity rear-facing
speakers because they become less efficient there's a sound quality hit up right off the
bat and for these multi block these multi box setups that I'm going to show later we
can establish fairly effective cancellation behind without sacrificing the sound quality and having
that out of phase component and also when you have an out of polarity speaker mounted in the rear it
really needs some open space so if you have some barriers or some blockage behind it it can really
screw things up so they're a bit temperamental and we leak so we'll stay away from those for this
it's more the Lego invention we've got into this is actually Harry Potter on vocals and we have
a stormtrooper from Star Wars playing I believe that's a guitar or a bass looks kind like a key
to me I'm not sure who this guy is he looks like another oh man I'm going to get some Harry Potter
but uh kind of like how the bigger the evolution or kind of how these sub subsystems kind of come
about here in the most basic setup you've got you know you get your band playing on stage and you
put a subwoofer on each side of the stage make sense looks good but there's some issues that
arise here if you want a picture in your mind a simple way to look at subwoofer coverage patterns
is wherever you are equidistant from the sources they will tend to be the loudest with if there's
no other outside effects like time delays or weird anomalies in the venue or building the cheer in so
here we're going to get what we call power alley we are equidistant from the two sub sources just
off to the sides of power alley you are still very close to the center the subs are very close to the
same volume but you're closer to one set than the other you start to get cancellations I'll
call those power valleys these are areas where we get maximum cancellation just to the either
suggest either side of power Valley this is going to be most apparent in outdoor venues
indoors we get reflections which will help dilute that to some degree and then as we go off there'll
be other areas where we get cancellations second third but for the most part just that first major
cancellation is our primary issue off to the sides as we increase the size of the selbo for setups
we increase or exasperate that problem the power Ally becomes stronger and we get
considerable narrowing in the horizontal domain it's important not to forget the vertical aspect
as well this power Ally if we're looking at equidistant or equidistant from these subs here
but we're also equidistant from them here and we'll also equidistant from them here so this
power value is actually not just an ally it's a complete disk or a half of a disk that goes
right down the middle of the stage and up into the ceiling as well and this is having both of
those or significantly undesirable aspects that can be reduced by using cardioid subs
now views cardioid subs we have reduced our coverage we have less behind so this power
rally behind is reduced in volume the amount of energy radiated towards the ceiling is reduced
but we still have the to know modes to power valleys and a significant reduction coverage
to the sides to help solve that a common thing to try was the set point of these subs outward
because we have an equidistant point here we get a little peak right in front instead
of having that peak here we can move that peak outward we can move this peak outward and now
we've slightly increased our horizontal coverage but it's still off to the side
going to be less than optimum especially with the larger scale setups other methods of doing
this to set up an L now you're equidistant point for this sub-array is at 45 degrees so it's a
simple way of increasing your coverage slightly without giving too complex and even though this
is pointed here you've got a little bit of power so now you've widened it again but still you're
not going to get significant coverage 90 degrees off-axis at this this area it's always important
to look at our equidistant points and check out our vertical in this setup we've begun to form
an arc so our maximum equidistant point from all subs is probably right in here somewhere
that means we've got significant energy headed towards the ceiling less-than-desirable all
right that's probably enough for this one in the next upcoming videos I'll cover some more complex
setups type of flown subs achieving cardioid with multiple enclosures and some of the concerns with
setting up a straight line of subs and creating a delayed arc and Oh get that dozen all right