all right i'm dave rat and let's do another adventure where we use simple gear to
demonstrate complex concepts i get some questions to these videos asking me why don't i use
audio precision why don't i have this highly complex test gear or i could do better using
you know the same gear that the manufacturers are using to create the spec sheets i could do
the same thing well can you see the the challenge with that if i demonstrate what the gear is doing
using the same equipment that the manufacturer has to demonstrate or show what they're doing
all i'm doing is repeating what they've already done i'm trying to correlate what is going on with
this equipment with the real world and what we hear so that we can utilize these pieces of audio
gear in an optimal way and we can make decisions and know what something's going to sound like
we know what polar patterns are we know that they're omnidirectional cardioid supercardioid
and figure eight and so on so we've got all these different patterns but that's much too simplified
for what really happens because what's the frequency response in the coverage area
in the on-axis well that's going to show up in the chart that's pretty straightforward what's
the frequency response off-axis it's constantly changing you'll see multiple polar patterns each
with different frequency response charts there's a different curve for every angle around and it's
a three-dimensional thing so the amount of data involved is significant as you go from cardioid
which is fairly wide omni goes to cardioid and you start to get a little bit narrower then you go to
super cardio and then you go to hypercardioid and then the next step is figure eight
which then picks up so much off the backside that it's almost like the front side again so
even though we're getting narrower and narrower in our coverage we're also getting louder and louder
on our off axis coverage and uh the other thing i'm going to look at is how do these
mics deal with distance when you're right on the mic when you back away so let's get started
what i've got here is a sound bullet by senect wonderful piece it's got pink noise generator
turn that on and i've got a single in-ear rubber banded to a sharpie and
i've got a couple microphones run into a little mixing board two of these four durometers hooked
up to this mixing board so one mic here and the other mic here so now what we can do
is calibrate so i'm going to put this in front of the article on seven and we will bring up the game
here until we get this meter right into the red so it's bouncing around in the red and we can see
that the peak is in the red and the continuous is reading minus 10 db so the 1db increments
on the meters there now we'll take that same thing we'll put it on the beta 58a there we go
okay so
now that we're calibrated
and
that's on-axis and we'll come around the side
let's do the same thing with the beta 58a
let's compare on-axis to on-axis
let's compare off-axis off-axis
and let's keep going around the back
and you may notice a difference go around it I'll do it this way
as you can hear
off-axis we've got a much quieter output on the Audix or m7
on the side here we can look at where that cancellation is
and we could actually put a pen here so there is our
there's our polar pattern for the no let's look at the audix
and it's somewhere right on there so not quite as wide the audix is about there
sure it's about there the monitor sound getting back into the mic
it's going to pick up high frequency sounds over here
but the beta 58 picks up high frequency sounds back here as well
you can hear that notice does not this is going to offer better off-axis rejection of
higher frequencies let's go ahead and look at another aspect i'm going to put this pen down
and we can see that it's bouncing around that minus 22 range
the drop off of the audits
the drop off of the cure
you can really hear a difference there
just for fun let's do another mic and um take a look at the audix
and let's do this Telefunken m80 and we'll do the same thing let's calibrate the set width
and the other one make sure we're good and let's go ahead and come around the side
and let's see that circle thing
and we can do drop off point them outward so we get a little less bleed into them
cool and we can see that the Telefunken is
kind of um not as drastic as the audix with the drop off it drops off a little slower it's kind
of halfway between the two or some version between the two how about an old school 58
let's try that calibrate
and off-axis
again we're hearing a lot of sound coming from the back of these
not as much rejection behind as the beta 58 so let's try a heil p
30 pr pr35 let's go ahead and calibrate that's a hot mic
and
so the capsule's up far into that um end there let's try it up here
now we're going to drop off really quick
you kind of know where the cure is by now
and it's similar at a distance which means as you back off the mic it's not going to drop in volume
very much and for a singer that really moves around the ohio is going to and the beta 58
and the sm58s are going to be pretty forgiving the m80 is going to drop off quicker and the
om7 is going to drop off the quickest oh let's do one more mic and we'll check out this Royer
figure-eight ribbon calibrated
so the front of the mic
or the two front
this is the front here it's a little brighter put the logo out facing the audience a little dollar
but you can use either side in here
listen though
the top of the mic so the nose traveling around this way so there's two balloons out that way uh
let's see oh one thing that's really interesting is when there's a null in a mic when you see a
polar pattern that's got like this no those little dips those are actually in order for
there to be a no and to have a cancellation we need a polarity reverse that means that
in us with a supercardioid mic that comes around like this and balloons out this way in polarity
out of polarity and if it does this in polarity out of polarity
in polarity so every time you get those no's there's a polarity verse because the polarity
verse and the no are intertwined the reason you have a null is there's a polarity of verse or
the null is a result of the polarity verse or the polarity verse as a result it's their
intertwine they're the same thing and like a figure eight mic is in polarity in the front
outer polarity behind and therefore you have a no all the way around the balloon that's two
balloons that are pinched in the center cardioid mic where you've pushed in a dimple into a sphere
there is no polarity reverse it just cancels out it begins it wants a polarity verse but there's no
signal there so it smells out or the polarity verse is equal to it so the polarity verse
in the in in polarity and out of polarity signals are the are equal at the null point and therefore
there's no sound picked up all right simple tools for complex concepts and thanks for joining
you