We took a look at our main sub phase relationship in
the near field now let's do the same thing in the far field so I've got my
speaker separated here and still got my sub here in the ground now I move my
main over there and that's what happens out in the field sometimes, right? We
don't get to always put our main right next to our sub and then I've got my
microphone over there farther into the room so let me actually measure the
distance 17.8 - 16.7 that's about 1.1 feet and if we want to find out what the
offset is in milliseconds and we multiply that by 0.9 to get one point
one time's gonna be one right yeah one millisecond so if I want to maintain the
alignment that I found in the near field I need to head over to my X32 and add
one millisecond of delay to the sub and this should actually be two point seven
right that's what we found in the previous video so I have my original
delay here that I measured to find phase alignment in the near field two point
seven milliseconds and now I'm just adding one millisecond because of the
distance offset for their arrival at the microphone cool so the next thing I want
to do is measure each of them solo and just make sure that their levels are
still hitting the target trace where I want them to be so I'll turn on my
target trace here and let's measure that
well this looks really bad right I almost have no information here in the
low-end well what is the problem here so there are three potential problems four
loko hearings right and the first one I think is really obvious signal noise
Ranger right when we started we had the microphone right up next to the speakers
and now we have the microphone far away and I've got to wear conditioners on
because we're experiencing a heat wave here in Minneapolis okay
so can i improve the signal noise right sure well normally you wouldn't be able
to do this in the field but just here in my apartment I can turn off the two air
conditioned so let's see if that's all right air conditioners off let's try it
all right much better right but I'm still still not getting very good
coherence here in the low end what's another way that I could improve my
signal noise Rachel well I could turn up the signal in the room right to get over
the noise floor and I don't want to bother my neighbors too much so as we
talked about in a previous video what I'll probably do is switch the signal
generator to pseudo random noise so that I'm not listening to the entire
frequency spectrum and annoying myself in my neighbors maybe but before I do
that let's make sure that I am close to the right level with my stuff
not quite so looks like the sub is going to need to come up a bit if we're going
to get up to the target taste and we're already at zero so it looks like the
main entrance to come down so here's what I'll do I'll actually just turn up
the preamp on my microphone here until I get the sub in place where I want all
right there we go so it looks like it's a one-note wonder right now but at least
we're getting up to where I want for my party tricks so I'll switch back to the
main
okay great so now at least I have a closer relationship to living my target
choice between my man and my sub so now let's talk about getting some better
data here I know I can turn up the signal that'll help me now so let's try
that first and maybe we'll head over to the spectrum view and see how much we
really need to turn it up
so first of all stop talking and we'll just measure the noise where the phantom
will turn on the signal generator and now you can see this is why we weren't
getting very good measurement down there we're not above the noise floor down
below say 60 Hertz now we may be your speaker isn't even playing that low but
let's turn it up and see if we can overcome the noise for
okay remember how I talked about we might switch over to pseudo-random noise
I think it's time to do that
okay it looks like we're not gonna quite get above the noise floor all the way
down here but potentially the speaker isn't even playing down there because we
can see over here well above the noise way okay
so I'm gonna zoom that it's doing the same that we should be plenty above the
noise floor in the sub now let's take a look oh yeah great so I better go over
the chancellor function here and now let's take a look at our main cool much
better data right I mean this is stuff that I can read let's save that and look
at the sewed
cool so some come til during here right this could be from a wall it could be
from floor and the only problem is that I would kind of like to see this data
here I would like to see the whole thing connect so we have a pretty good we have
pretty good data here but I think I can do even better by putting microphone on
the ground and removing the floor balance now that's not totally realistic
because we're not going to be laying on the ground listening to the show but at
least it will allow us to look at these phase relationships with a little bit
more and we're not having such a huge hard time in this tiny room where it's
be quiet out in the field though in highly reverberant spaces where you are
very far from the speaker and therefore you're at that point just measuring
reflections more than you're measuring direct sound using a ground plane
measurement can help you in those can touch some tough situations so let's try
and let's go back to our me
and let's add a few more averages let's go to two seconds of averaging and see
if we can get even better here
cool let's just compare those so here's the main I had before here's the miss
periodicity here's the main I had before here is now my ground playing
measurement and you can tell I just have a little bit better coherence okay
always in pursuit of better data so I'll say this and I'll call it main so and
one more thing remember in a previous video we talked about how to unwrap this
phase let's do that now because this is a little bit hard to read okay
so this might be even easier right so now I can just kind of look at this one
line coming down here and I'm not moving yet
Reverend's so I'm gonna go with 40 milliseconds here in the delay I'll stop
talking for a second and recapture this
oh now let's take a look at this up
okay now we did a lot of work here you notice that we jumped through a lot of
Hoops to try and make this easier to read out in the field I'll usually just
go straight to that I'll know that I need a loud signal to over overcome you
know for signal to noise ratio maybe a ground plane measurement and I'm going
to need to add some delay so these are things that we would go through quickly
out in the field all right so let's take a look at the face here good news is it
looks like we are already aligned to this area but I need to look at the
crossover region right so how do I find the crossover region well you remember
from previous video that we're gonna offset our sub trace minus 10 DB then
plus 10 DB so we can find the points of interaction between the main and sub of
10 decibels so let's go ahead and do that now I still have my main trace it's
like an ear I'll offset it 110 so it looks like down to let's say 85 Hertz
we have interaction and then up to 120 so 85 to 120
we take a look at that we rotate this around so it's a little easier to read
okay this is tricky right because we are in time here and we know we can add a
little we know we can probably add a little bit of delay and bend that down
but then we're gonna need more delay up here because we even farther apart this
is where things start to get tricky and we have to really think about triage
right so where are these two speakers interacting where their levels are
closest well they have the same level here and then through here and then
there's a greater offset down here so let's really focus on getting this area
where they're really close in level and therefore we'll have the most amount of
interaction as close as possible now we don't have a virtual time shift like we
do in Sat live and smart but we can just play around with this delay and see what
that does to the trace so let's experiment with adding some delay to the
sub and so inversely if we want to just play around with that without actually
doing it in our system processor we'll just subtract delay from the delay
locator here and see what that does to ours so we're still measuring the sub
let's start so let's start subtracting the leg from the delay locator here and
that will give us the same effect as adding delay to our stuff oh you know
what I just realized I was talking about the wrong trace so I was looking at the
main trace up here thinking hey we need to add the lay to the mate so in that
case we need to go the other direction let's save the sub trace and then go
back to the main trace and see what happens if we had to lay there so let's
go back to 40 and switch over to the knee
there we go
cool so this might be good well within 3045 definitely within sixty degrees
here where we have the most interaction and then down here we start going out of
alignment and we might be able to find a happy medium where within sixty up here
and maybe still within sixty down here let's play with that
cool so I think this is probably the best working get we are within 60
degrees here and within 60 degrees down here so we started at 40 we came down to
thirty seven point seven forty minus thirty seven point seven is two point
three milliseconds at two point three milliseconds of delay to the main we're
at two point seven now so we need to go up to five and we'll go back to forty on
our delay locator
there we go so we started here where is that we started here with our main we
added 2.3 milliseconds with the light to the 2.7 for a total of 5 milliseconds
and we ended up here so let's take this old one away ok here's where we are now
so now let's turn them both on together and check for summation
all right looks like summation here to me we can offset this trace and see by
how much five six yep so we're getting a full 6 TB of summation here and then
less than here 1 3 so 6 TB of summation up here 3 down here and then after that
the subs gonna move into isolation ok we went through a whole lot of stuff in
this video really my intention with this video is to just give you a taste help
you get started help you start taking your first steps so this is what I
recommend that you do it huh or in your warehouse or wherever you can get to
practice practice measuring Amane the sub practice combining speakers in the
near field where it's easy and you're a better signal noise ratio then practice
moving into the far field dealing with the problems that come up getting good
data looking at level and phase relationships reading the graph and then
starting to see what changes you can make to make to speak speakers play
better together alright if you have an idea for how I can improve this process
or if you have any questions please let me know by commenting on this video