hey my name is Dave brat and I'm gonna
talk a bit about Mike polarity onstage
Mikey I did an article about this a
while ago for pros on web and then I do
a video as well people like to watch
ok that'll goes this way
pushes the push of the head out
which is a positive pressure on the
microphone which sends out of the wire a
positive voltage
when the head bounces back the other way
comes this way we get a negative voltage
next so basically if we were to look at
that sine wave pushes out the first
thing we get is a positive voltage and
then I say we get a negative voltage
alright so we got the kick-drum here
Peter
drum drum bearing sits right here on a
drum throne and
behind him let's put a speaker giant
drum fill and in this drum fill or some
big speakers
and we'll put a mic over here and we'll
plug this into a mixing board
kick drum pedal goes this way hits a
drum creates a positive pressure wave on
the microphone positive pressure wave if
your system is wired correct will create
a positive pressure wave here and your
speaker will move outward
so we have speaker moving towards
the drummer and
we have the drum head moving away from
the drummer
then the head naturally rebounds
backwards
creates a negative wave comes all the
way around but it's a negative way and
so our first experience is
speaker moving towards with the drum
head moving away and the next experience
is the drum head bouncing back and the
speaker moving back
if your let's take a look at this
scenario here we have somebody in the
middle of this
we have this one moving towards that one
moving away this one moving towards that
one moving away
think of your home stereo speakers what
if we wired them like that so this one
moved away from you and this one moved
towards you they would be out the phase
out of polarity ideally for maximum
low-end summation coupling we would have
them both moving away at the same time
or both moving towards you at the same
time which is the opposite of what we're
seeing here
so how do what we do to correct this if
we hit the polarity switch in the mixing
board which is down here
then he hits the drum or she hits the
drum it creates a positive pressure
because all the way through it goes into
the polarity switch which turns that
positive pressure whoo a negative
pressure a negative voltage negative
voltage comes into here and this moves
away so when the drum head moves away
the speaker moves away when the drum
head moves back the other way the
speaker moves back now we have an
impotent in phase or in polarity
situation with a kick drum we are miking
the back of the head when the impact
hits it
it puts a positive pressure wave on the
mic make better snare drum
and I'm drummer dude over here number
real tall skinny guy big long like we
have a drum fill back there and he hits
the drum or she hits the drum it moves
down and away you got a little mic over
here
creates a negative pressure wave the
drum is moving away from the drummer and
the negative pressure wave causes the
speaker to move away from the drummer's
here snare drums in polarity let's go
back to the kick drum example in there
John
and here's our drum monitor
when this drum moves away and you have
an outer polarity situation and the drum
fill speaker is moving towards the drum
head moves away the speaker mint moves
towards it actually pushes and impacts
the drum head and moves it farther away
which then creates more positive voltage
which moves the speaker farther out
which moves ahead farther away when the
head finally reaches maximum or whatever
resonance is hit it starts to come back
creates a negative voltage and the
speaker pulls back to head pulls back so
what you get is this resonant situation
and that resonant situation is what we
call
feedback
and so in order to minimize feedback we
would want these to be
cancelling each other out when this head
moves towards it's creating us
impulse it moves the speaker towards
when the head's moving away quit to
speak about hitting the polarity reverse
we actually can use the speaker to
dampen the head slightly and minimize
feedback and
increase
impact
for the drummer
so that's a pretty simple
that up there hope that makes sense how
do we know what it is how do we test it
pretty simple stuff there to
basically just turn it on I like to on
this kick drum we'll draw it again kick
drum we turn on with no e Q
we turn this mic on and we turn it up in
drum fill go out the DF
and
we'll bring it up till it starts to
feedback
feedback do we hit have a B
and we might touch the head a little bit
we set get a little feedback on it then
we will hit the polarity reverse button
on
the channel if the feedback when it's
just at that verge of feedback and
decides to take off if the feedback
increases
then we hit this button again because it
made it worse if the feedback reduces
then we leave it in alright so the
number one thing you do
number one is
determine
kick
pull there a TV
because once you've determined the
kickdown polarity versus the drum film
assuming that the rest of the stage
equipment sound system is wired the same
and correctly
you can now build your polarity system
for the rest of the stage or for at
least the rest of the kit
you'll find that some monitor rigs are
pin to plus and some are pin three plus
a pin 2 plus rig will have a positive
pressure on the microphone which means a
diaphragm is will begin or create a
positive pressure a
pin 3 a positive pressure on the
microphone will create a negative
pressure
all right so now we've determined our
kickdown polarity let's say I came from
has to be polarity reversed
when we mic the back of the drum on on
beater side
and we have to kick mic so the second
kick micro polarity averse next Micha my
mic chart is a snare top
that's not to be polarity verse that'll
be in so we'll call that fun flirty side
by there versus next one's a B snare
bottom we're miking be non stick side of
the head to reverse that
hi-hat will be in polarity because I'm
Mike in the stick side I
got next rack I typically mic from the
top but my even the top it'll be
in-phase
floor drum same thing
ride cymbals typically I meant I am Mike
my ride cymbals from underneath
non spit non beater side I typically
fate polarity reversal now we can take a
look at that we've got a rap tom here
we've got a ride cymbal here we got a
mic on the bottom of that but a mic on
the top of this now look at which way
the mics are pointing for this one is in
in polarity and this one here is
underneath then we'll call this out so
again if you actually
from a level playing field you can
actually say that see that this mic
because it's pointing up is clear
reverse
if this mic was up above let's say that
rides him it was up here and you had
this mic up here pointing this would
actually be a summing point this would
actually because this is flipping
polarity and turned around in direction
would pick up the Tom in phase I don't
you can get into many depths of the
complexities there pretty much what I do
is if I'm Mike in the stick side it's
the opposite polarity as if I'm liking
the nonstick side and I determine my
starting point off my kick drum and I go
ahead and click my polarity of our
switches accordingly from that point
forward what makes in front of house
since unknown mmm I will always I will
just start with the kick and cakes
reversed and snare top their bottom
reversed and
under heads and any under head cymbals
reversed