DR-7100 Frequently Asked Questions

Question number FAQ-1125

How to display sound data from a sound level meter or microphone as sound pressure level using Oscope Basic (Part 2)

Oscope 2 Ver.2.7 and later versions include a function that allows you to calibration other data files using calibration signal files recorded with the DR-7100. This document explains how to use this function to calibration audio data.

1. Import the calibration sound file (containing calibration sound) and the data file you want to calibration into Oscope. Ensure that the equipment and amplification settings used for recording calibration sound data are the same as those used for recording the data.

The image above shows sound data recorded using the DR-7100 imported into Oscope. The upper file contains calibration sound (94 dB), and the lower file contains the engine intake sound. The unit of magnitude is "V".

2. Use the calibration sound data file above to perform calibration to sound pressure. Select "Signal calibration" under "Custom" in the Oscope toolbar. The signal calibration window will open.

① Select the file containing calibration sound as the "calibration Signal (Reference Signal)". Next, select the data file you want to calibration from the "Select calibration Items" section and check the checkbox.

② Under "calibration Method," select "calibration with FFT." The "calibration Signal (Reference Signal) Interval" is set to "Entire Interval" by default, but since the entire interval is too long, and the signal may not be stable at the beginning of the measurement, select an interval where a stable signal is output. (Please select an interval of several seconds to about 10 seconds.)

③ Set "Scale" to "Decibels", "calibration Target" to "Overall", and "Unit" to "rms".

④ Set the "Target Value (Level after calibration)" to the sound pressure level of calibration sound (in this case, 94 dB), and click "calibration Calibration".

*If you check "Output on a new channel" and perform calibration, a new data file will be created with a rewritten calibration scale, while the original data file remains unchanged.

The top file is the original calibration sound data, and the third file from the top is calibration sound data after "signal calibration". Also, the second file from the top is the engine intake sound data, and the fourth file from the top is the data after "signal calibration". You can see that in calibration file, the signal unit has changed from "V" to "Pa". The fifth file from the top is the result of "effective value calculation" performed on the top calibration sound data. The sixth file is the result of "effective value calculation" performed on calibration sound data after "signal calibration". It went from -28 dB to 93.999 dB.

Last updated: 2017-07-12