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  

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