Shure MXA910 Manual page 21

Consider the following when determining a mounting height:
• The pickup pattern of the ceiling array is narrower than a shotgun microphone, and therefore it can be placed farther from
the source than any other microphone. While the web application shows an ideal coverage zone for each channel, keep in
mind that there is no specific barrier at which the audio degrades or gates off. Lobe sensitivity data is available for each
width setting in the product specifications.
• Like all microphones, tonality changes as the distance from the source increases.
• The intelligibility scale helps to predict how the microphone will sound at a given height.
• The coverage area of the lobes increases at farther distances.
[1] Room conditions: RT60 (reverb time) = 500 ms @ 1kHz, A weighted room noise = 40dBSPL(A)
[2] IEC-602682-16 standard
Intelligibility Scale
The intelligibility scale objectively compares the acoustic performance of the array microphone with a cardioid gooseneck mi­
crophone at various distances. This information is useful for predicting how the array microphone will perform at a given dis­
tance and to determine an ideal mounting height. The data in the intelligibility scale table is derived from measuring the micro­
phones to meet an equivalent value from the Speech Transmission Index IEC-602682-16 standard.
Distances With Equivalent Speech Transmission Index Values
Ceiling Array Microphone (Distance to Talker)
6 ft (1.83 m)
8 ft (2.44 m)
10 ft (3.05 m)
12 ft (3.66 m)
Data was collected in a typical huddle room with the following measurements:
• Reverberation decay time: 500 ms @ 1kHz
• Noise floor: 40 dB SPL (A-weighted)
Note: These values are specific to the described room. In a well-controlled acoustic environment, the array microphone may perform with equivalent Speech
Transmission Index values at even greater distances. In highly reverberant rooms, the performance is less predictable.
A = Distance between array microphone and talker
B = Distance between cardioid microphone and talker
Cardioid Gooseneck Microphone (Distance to Talker)
3.75 feet (1.14 m)
5 feet (1.52 m)
6.25 feet (1.91 m)
7.5 feet (2.29 m)
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