So can you complete a crossover alignment with a simple
distance measurement? I think the answer is no and in this video I want to talk
about why I think that is and maybe what you can do instead.Sso recently I
published an article called are you still trying to align your subwoofers
with an audio analyzer where I go through 13 common ways that I've tried
to complete a crossover alignment in 13 ways that I failed and again that
doesn't mean that you shouldn't do these if they work for you definitely use them
and I think you should try them all and let me know what's working for you I'd
love to hear about it none of them have really worked reliably for me and that's
what I'm gonna talk about today this seems like such a great hack and
honestly I guess it is it's a good shortcut because 66% of the time you're
gonna be right so if you want to roll the dice 66% of the time you're gonna
get some amount of summation and 33% of the time you're gonna get some amount of
cancellation so I don't know do you want to roll the dice well let's let's look
at how this might work out so over human map xt have set up a couple of different
speaker arrays we've got this pair here and then I've got another pair so this
is I think leopard and 900 LFC and then I've got another pair I'll show you in a
second so I also have a helpful little tool here and this tool is basically
just going to quickly help me convert distance to time okay so if I were to
get out my laser distance measure and I were to see that
okay the distance from my measurement position is 22 feet and 18 point 23 to
the sub so let's put that into my little tool here twenty two point zero eight
and eighteen point twenty three okay this is gonna do some calculating and
then says hey converting that to time you need to delay the sub by three point
four one milliseconds I say great I can do that so over here I'll delay the sub
by three point four one and my second pair down here three point four one
and now we can compare so I hit predict here and we're predicting at a hundred
Hertz then this isn't great it isn't terrible but what I see here is that
we've got our summation kind of pointed down this way and then we've got
cancellation here so I guess you could say that we're splitting the difference
it's okay it's it's not perfect but we roll we've rolled the dice and we got
some summation through our audience playing there so let's look at our
second speaker array this is the Milo and the 650 P and I'll hit predict and
this is a little bit different story right so now we've got cancellation
through part of the audience and we've got summation to another part of the
audience and yes it's always going to be like that right we can only get perfect
summation in one point and then errors are going to sort of spread out from
there but as you can see with this method we're not even really getting
perfect summation at this microphone position and that's because we've kind
of rolled the dice in terms of phase alignment we may be closer with our time
alignment by using this method but our phase alignment might still be off now
some of you might be saying you have the microphone too close you need to set it
back here you should measure at like 3/4 or back of the audience so let's try
that next so I've got my fourth mic here and I've already done these measurements
so let's redo our calculation forty eight point eight seven and forty seven
point seven four okay so I need to delay this up by one millisecond because I'm
only off by about one foot here so I can do that I'll put in one millisecond for
this pair and one millisecond for this pair and let's look at this Milo 650
peepers
cool so different result here right so now we
have cancellation through half of the audience and we've got some summation up
here and like a tiny bit of summation back here not ideal and let's take a
look at our other pair the leopard and the 900 LFC now we've got summation
through a large portion of the audience and then cancellation up here at the top
so as you can see if we only use distance offset and we don't really know
the relative phase relationship before we start then we're really rolling the
dice and we have a 33% chance of getting cancellation and a 66% chance of getting
summation so that's why I think this method of using a simple distance offset
without knowing the relative offset ahead of time can be risky and doesn't
work reliably and in the next video I'm going to show
you one more way that I think doesn't work and is common and then I'll be
getting to the more reliable method that I think you should start using instead
so let me know if you've tried this if you've had success with this people have
told me stories about it already and I'd like to hear yours all right thanks
sound design
you