Setup guide
Dirac Theater Setup Guide Version 1.01
Document # 9301H40300V1.01
6
Important information about the choice of microphone positions
The microphone positions should be spread out regularly (roughly evenly over the listening area), but
somewhat randomly, in the various listening positions that will be used by the listeners. The microphone
height should be consistent (the height of a seated listener’s ear) to capture all relevant variations that
occur within the listening region. The sound quality will be optimized for the positions where
measurements are taken. It is always better to measure in relatively centered positions than in extreme
positions near the borders of the listening region. Keep the measurement positions as far away from walls
and other objects as possible. Aim at “free-field” positions.
Microphone Placement
Refer to Figure 2 during this description.
The sweet spot, which you will attempt to tune, is the middle 50% of the rows of the center section. To
determine where to place the microphone to collect samples, you start at the screen and go up 25% of the
depth of the theater, in the center section of seats.
At that row, place the microphone at the second seat (from the aisle). Take a measurement. Then move
the microphone six feet further along the same row and take another measurement. Repeat again, to get at
least four measurements in that row, each one six feet apart.
Then go back further (in the same center section) no more than two rows. Place the microphone at the
three midpoints between the four measurement points of the first row, and take measurements.
Next, go back two more rows and repeat the four-point plan used with the first row. Then go back two
more rows and repeat the three-point plan used with the second row.
Continue this alternating pattern until you reach the row which is 75% of the distance back from the
screen. This row marks the rear limit of the measurement area of the center section. A typical theater
will necessitate 9 to 18 samples.
Figure 4. Microphone placement for a large theater.
Smaller theaters may use fewer positions.