User Manual
Townsend Labs Sphere L22 Precision Microphone System Guide Sphere Plug-ins
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Input/Output Meter
Click the meter to toggle between displaying the input and the output levels.
Polar Meter
The Polar Meter™ displays the approximate amplitude and direction of sound arriving to the mic. The
Polar Meter can be particularly useful to determine where bleed from other instruments is coming
from. The moving yellow line in the Polar Meter shows the approximate amplitude and direction of
arriving sound. The green line shows the polar pattern of the currently selected microphone.
The Polar Meter in Figure 3-6 shows a sound source 135° off-axis, which in most cases would be
considered bleed. The user would create a polar pattern to reject as much of this unwanted sound as
possible. The two “shadowed pie wedges” show where the polar pattern has the most rejection. As-
suming the desired (on-axis) sound source is muted, the off-axis bleed can be minimized by lining up
the area of most rejection to cover as much of the yellow shape as possible.
Figure 3-6 Polar Meter showing source at 135° off-axis
The Polar Meter cannot differentiate between sound coming from the left, right, up, or down. In this
example, sound coming from 135° to the right is displayed as coming from both 135° to left and 135°
to the right. This interpolation is accurate because most microphones, including the Sphere, are bilaterally
symmetric. The polar pattern is the same whether off-axis to the left or right, so there is no way to
adjust the pattern to reject sound on just the left or right. In general, we recommend using the Polar
Meter as a guideline, and then dialing in the exact pattern by ear that produces the most rejection.
There are some inherent inaccuracies in the Polar Meter due to the mic
’s proximity effect, and low
frequency content can distort its response. If the distance to the source is known, this can be com-
pensated by enabling
OFF-AXIS CORRECTION and using the distance controls to produce a more accurate
Polar Meter response.