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RADIO SHACK 33-2050 SPL METER

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The Radio Shack 33-2050 Sound Level Pressure Meter is useful for measuring sound intensity, determining speaker efficency or developing quick frequency response plots for loudspeakers. Power is supplied by a 9-volt battery, so the meter is completely portable.

To create quick frequency response plots, use an Audio Test CD and read the sound pressure directly from the meter. A link to a free Audio Test CD is provided below.  For more detailed plots, you can use a wide variety of commerical and free software. A link to Frequency Response Plotter Software with built in corrections for the 33-2050 meter is provided below.

Radio Shack 33-2050 Sound Pressure Level (SPL) Meter

For more accurate results while testing loudspeakers, it is best to do the measurements outdoors in a quiet and spacious area. The Radio Shack Analogue SPL meter is not very linear and will need to be corrected. Use the following correction table with the meter set to "C" weighting and "Slow" response.

Frequency
Correction
  
Frequency
Correction
10 Hz
+20 dB
  
500 Hz
-0.5 dB
12.5
+16.5
  
630
0
16
+11.5
  
800
0
20
+7.5
  
1.0k
0
26
+5
  
1.25k
0
31.5
+3
  
1.6k
-0.5
40
+2.5
  
2.0k
-1.5
50
+1.5
  
2.5k
-1.5
63
+1.5
  
3.15k
-1.5
80
+1.5
  
4.0k
-2
100
+2
  
5.0k
-2
125
+0.5
  
6.3k
-2
160
-0.5
  
8.0k
-2
200
-0.5
  
10k
-1
250
+0.5
  
12.5k
+0.5
315
-0.5
  
16k
0
400
0
  
20k
+1

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