I have a friend that seems to find a polarity inversion on almost
every show he works on and I almost never find one so I'm either not
looking hard enough or I'm just really lucky. Let's talk
about how to identify a polarity aversion in Smaart. This can be a quick
easy process it's one of the very first things we do in the verification step of
our sound system tuning roadmap and it's a thing that you could actually do in
the shop the day before so it doesn't need to really take up any time once you
get into the field if you know exactly what speakers you're going to use but if
you're the kind of person that just has to show up and use some unfamiliar
equipment this is probably a step you want to go through so that you don't
have to find out later on what you have speakers up in the air that one of them
has a polarity inversion and now you need to like take the box apart or take
it out of the rig or whatever so what I'm gonna recommend is that you just
turn on delay tracking and then basically go from speaker to speaker and
just keep an eye on your phase trace here if you have an assistant that can
make it even easier because then you can just stand and look at the analyzer and
you can solo speakers one at a time and your assistant can like to move the
microphone around but if you're by yourself then maybe you have a tablet
that you can walk around with or you might need to move the microphone then
come back and look at the display so let's do it so I'll push play on my
measurement I'll start up the generator
and I don't hear anything okay cool so I'm not even really gonna pay attention
to the magnitude trace here in fact let's go ahead and do this
that's actually really hard to see though
let's go back to a regular display
all right delay tracking on and I'll stop talking and save the trace
then all I need to do is move from speaker to speaker and compare
you
okay this one checks out looks pretty good I can save if I want to reference
it later okay now I'm about to move on to the sub but remember as we talked
about in previous videos the delay locator automatic delayed tracking
doesn't work so well with the sub so I'm going to turn off the delay locator
before I switch to the sub and I'm actually going to use the same
microphone position because these are matched speakers that they're designed
to work together so my expectation is that with them set up the way they are
with one on top of the other I should not see a palladium version so let's
just try it that way first
mmm I don't know about this let me zoom into the low end okay this looks like a
polarity inversion to me okay cuz we've got what 0 about around 118 and then
we've got negative 180 and positive 180 around that area okay so I believe we
have identified a polarity inversion so I could do that at the mixer or the
speaker processor let me take a look at the sub though because sometimes those
have a polarity inversion switch and yes it turns out that it was set to reversed
who did that I don't know but I'm glad I found it okay so I'm glad I checked and
didn't have to find out later and I'm glad it was as easy as that and now we
can see that where was 180 degrees out before now we are in alignment again
another helpful tool to find a polarity inversion is the impulse response and
you can open that up if you don't already have it open by clicking live IR
and smart so let me start up the generator
hit play my measurement
all right so here's my impulse response and if i zoom in
oops I need to be able to see the top and bottom
then I can see that it Peaks down first and then up that means somewhere in my
system there's a polarity inversion but all I really care about is that they all
match so this would be another good thing to look at as I'm saving my traces
and move them from speaker to speaker just make sure that they all peak down
first and I realize this window is a little bit small so it's a little if you
want to head over to the impulse response window and then it starts out
looking like this but if I go to option one that zooms in and then I can right
click and zoom in even more there we go so now it's really obvious that this one
is peeking down so what I would do now is just go from speaker to speaker and
hit play so let's try that so let's go to the other speaker
there we go so I've now verified that both of these speakers are peeking down
first in the impulse response here and that they have matching polarity as you
can see in the sub window this is not so helpful I would have to I guess a zoom
way in like this and now I can see that it Peaks down here but still a lot
harder for me visually to see than just when I was looking over here on the face
response in the transfer window so that's why I don't actually switch over
to the impulse response that much but it is another good tool to have open so I
guess what I would do most of the time is stay in the transfer window and just
have this impulse response open and you know command I can open and close it
really quick so in case I'm wondering like are these really - I can just have
another piece of information there and that is how you identify a polarity
inversion and smart if you have another way of doing this I'd love to hear about
it I'm always trying to improve the methods that I use and share with other
people so comment below this video and let me know