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Hi everyone Dennis Foley from acoustic fields. Today we are going to talk about speaker positioning
and listening position. What are the formulas for that in a room, what is the common knowledge
if you will about how to start, how to finish, and what we find is that there's a process
set that you go through that counts for 3 different variables. The rule of thirds, room
response, and critical distance. We are going to go over each one of those in this video
and give you an idea of how each one works. Each one is a different measurement. Each
one involves a different listening position. And it is a subjective approach after a while,
but these three dimensions and variables if we look at them closely will give you a pretty
good idea of your listening and speakers need to be in your room.
Okay, let us start with the rule of thirds. The rule of thirds says divide your room into
thirds. Rectangular room into thirds. You have a cross line here and a cross line here,
and then we have 1, 2, 3 sections to a row. The rule of thirds say is, place your speakers
left and right channel along the first third dividing line of the room. Obviously your
listening position goes on that other division for the second third. So that's what rule
of thirds says. Divide your room into thirds and position your speakers left and right
along that first third line, and then you're listening position along the second.
Our second way of finding out where our speakers and our listening channels should be is called
the room response. Well, room response, what are we doing? We are going to take a response
of the room. We are going to run some pink noise through our speakers, and then we are
going to measure it with a microphone. We will have to figure out the response curve
of the room where it is doing what, and then we know what speakers in that position will
give us to produce a road response curve. Then we move the speakers, measure some more,
move them back a little bit, measure some more. Time consuming, but there's software
out there that has done the work for you, so if you do not decide on the drivers and
the number of low frequency drivers you have, software can give the room response of the
room without having to do manual legwork. So critical distance is our third way of measuring,
giving us a rough idea of where we should put our listening chair and speakers, and
critical distance, we had the rule of thirds which divided the room into thirds, and then
we had room response, which is the natural energy signal detected into the room, and
the room's response measured, and that particular speaker location. You have to do a lot of
trial and error to find the correct location. There's software that will help us with the
actual location of the speakers and the listening position. The third thing is critical distance,
that's more room acoustics. What is critical distance? It is the direct energy from our
loud speakers and all the refractions from the room somewhere in the room towards the
back third of the room where the direct energy from our speakers and the reflected energy
from our room are equal. So in critical distance, we have a situation where we are taking more
of the room acoustics into play and how the room is interacting with the direct signal.
So we have a situation where critical distance is more about room acoustics.
So our speaker listening position journey starts we need to find the right positions
for our speakers and right position for our listening potion. We are going to take it
in those three areas, room response, critical distance, and rule of thirds, and the rule
of thirds is dividing the room into thirds, positioning our speakers here, and positioning
our listening position here. Then we have critical distance which is more of a balance
between the room and the direct signal from the loudspeaker, then we had a room response,
which was measured and produced a frequency response curve. So we have the three general
guidelines to go by. So let us take some examples, so we get a handle on what it would really
be like in terms of positioning. The rule of thirds if we put our speakers here and
we put our speakers here, we know that our listening position is going to be here. Because
it is going to follow the rule of thirds. Okay. Critical distance what we find is that's
a position about a foot to a foot and a half behind when you divide your room up using
the rule of third method. So it is a little bit different positioning than using the rule
of thirds. Room response we find is in a different position. It is even in front of the positions
for rule of thirds, it is even front of the positions for critical distance. So we have
these three areas right here that the three different rule of thirds, the critical distance,
and the room response gives us in terms of where we want to sit. And how do we find out
which one is right for us? The only answer to that is to try it. But your boundaries
are critical distance and room response, and you'll find that your listening position is
somewhere between those 2 as you test it out, so get a chair that has casters on it and
move back and forth between these positions and you'll find the right listening position
for your particular room size. Thank you.